Production and shaping of steel and steel alloys

Description

[0002] The invention relates to direct production and shaping of steels and steel alloys from raw materials to finished products. Major goals to be achieved are that with the use of relatively impure raw materials, to produce high quality products with minimum of energy consumption, no pollution contribution, low investments and high adaptability to controls.

[0003] Present day steel industry is in a state of stagnation, as new developments are not taking place. Conventional processing routes are lengthy, high energy consuming and polluting to the environment, water and atmosphere and not liable to adopt modern controls. The present invention is meant to eliminate these problems.

[0004] Present production routes may be broadly divided into two main categories. BF (blast furnace), BOF (Basic Oxygen Furnace) route, and E.A.M (electric arc melting) route. BF-BOF route require high quality raw materials and agglomeration of charge (sintering, palletizing and sized iron ores preparation) and changing of coal to sized coke. Agglomeration process is required, due to specific configuration of a major production unit namely BF of this route, and in itself is not a step toward desired purpose. In agglomerated material more time is required for a reduction or combustion processes to complete.

[0005] In BF, BOF process there is high percentage of impurities ( 3.5-4.% C, +variable amounts of Si, S, P ) in the liquid iron from BF which are eliminated down to low values in BOF process. In a third step excess oxygen from the steel produced is eliminated and alloying metal additions are made with stirring.

[0006] Liquid steel is carried to a shaping process where steel is given a desired form, by passing through special shaping moulds. Heat removal, required for solidification of steel, is done by means of high- pressure water cooling jets. This process introduces internal and external defects in the casted product. Steel has to be given a cooling/solidification interval before performing the rolling operation.

[0007] Steel is reheated to carry out the rolling operation. Surface scale is formed which is removed with water jets. This operation lead to non-uniformly heated material, which later results in non-evenly rolled product, produces dirty water containing scale, and scale sticking on the metal surface.

[0008] In cold rolling plants pickling operation and ammonia type annealing process are major polluting operations. Pickling is injurious to steel surface as it produces grain- boundary weakening.

[0009] E.A.M steel and steel alloys production route mainly uses steel scrap and ferro alloys. Ferro-alloys are produced in an- other electric arc melting set-up. The quality of steel produced depends upon the quality of scrap used. Scrap is manually selected and prepared. Large scrap material is discarded because it contains numbers of elements not required in steel. These elements are Cu, Pb, Sn, Zn, noble metals and new elements being introduced from modern electronic waste products.

[0010] From the present arc furnace set up, product gases from the furnace can not be taken to impurities removal and gas cleaning arrangements and are discharged to the atmosphere. Slag is also dumped to the environment.

[0011] New technology should be introduced to recover metals from the scrap before the material goes to steel making furnace. This must be done both due to environment and economic consideration. Large quantity of valuable elements is lost every year.

[0012] Presently E.A.M route is attractive as steel from scrap is produced at cheaper cost as compared to the major integrated route. E. A. M is also major alloy steels production process. Steel scrap is melted by electric input and alloying elements are added and temperature raised higher than the melting point of major alloying elements (chromium) through the introduction of oxygen. Afterward carbon is reduced to very low value by blowing inert gases and oxygen though the steel melt and vacuum degassing.

[0013] Diversified charge materials may be used for the direct production of steels, and from environmental considerations there is need of processing of a throw away by product from copper nickel industry. It is an iron sulfide ore containing nickel and other valuable element like cadmium and arsenic. This type of material can be valuable for the production of alloy steel with the introduction of chromium ore. Through new technology concentrated sulfur dioxide should be produced which can be directly used and the roasted product may be processed like scrap for alloy steel making.

[0014] In certain part of the world iron ore has higher than specified amount of alumina and silica contents. When processed this can become a cheaper source of high quality magnetite and can be used for steel making. Various metal oxides obtained can be mixed in appropriate ratio for alloy steel production.

[0015] Further there is need of developing techniques where raw-materials of different nature can be used with minimum of diversity from a main production line. Materials should be usable in as available state or with reduction in their sizes. Ingredients not required in the steel composition should be removed and recovered. Repeating steps with change of vessel in the main production line should be minimized or eliminated. Steps leading to pollution and energy waste should be changed to gainful utilization of energy and by-product materials.

[0016] In the following basic processes are described based upon which a new technology to fulfill the above said aims may be achieved.

[0017] 1. Performing chemical reactions for cooling or heating.

[0018] Performing endothermic reaction in direct or indirect contact with the processed materials is used for cooling of materials. A comparison of cooling by performing endothermic reaction and cooling by water is given in the following. A reaction between a hydrocarbon and an oxidant producing elementary gases is given as following.

(i)CnHm+nCO2=2nCO+m/2H2

(ii)CnHm+nH2O=nCO+(2n+m)/2H2

[0019] Representative example is given in the following:

CH4+CO2=2CO+2H2 ΔH=+60,000K.cal

[0020] Added to this is heat absorbed by the reacting gases to reach the reaction temperature (assumed here as 1000° C.)=approx. 18000 K.cal

[0021] Total heat absorbed is 88,000 K. cal/kg. mole of CH4. If water is used to cool steel from 1000° C. to room temperature it will absorb about 15,000 K.cal/Kg. mole of water. Add to this exothermic heat of the reaction

Fe+H2O=FeO+H2 AH=5,000 K.cal/kg. mole of wustite

[0022] The net cooling effect is 10,000/Kg. mole of H2O. The thermal resistance of the oxide scale has been neglected. It can be seen that heat removed by water-cooling is about one eight of that removed by above given endothermic reaction. Mixtures of gases, which absorb heat during chemical reaction, are termed as endothermic gases and the process is called chemical cooling. Energy is recovered by performing endothermic reaction of the following type

(i) CH4+CO2=2CO+2H2 endothermic

(ii) CO2+H2=CO+H2O endothermic

[0023] Reaction (ii) will be used for the elimination of entrapped H2 in steel at high temperature (>900° C.) Performing reaction (ii) in the reverse direction will be used for the production of H2 (exothermic shift reaction). In this write up mainly CH4+CO2 mixture is mentioned for endothermic reactions, but it may be CH4+H2O as well. The reforming reaction CH4+CO2 will adequately take place if temperature is about 1000° C. or higher. If the temperature is lower than 1000 C. catalyst is required. The catalyst has to be contained in a closed vessel and heat transfer will take place through the walls of the container. At limiting temperatures of about 700° C., pressure is also required. The term reforming gases is used to describe endothermic gases. H2 or CO can be produced by carrying the following reaction by excess CO2 or by excess H2O over a catalyst.

CO+H2+CO2=2CO+H2O, ΔH endothermic

CO+H2+H2O=2H2+CO2, ΔH exothermic

[0024] CO2 and H2O can be removed to get CO or H2. These steps can be repeated to get the gases of required purity. When temperature of the system is low and energy transfer by reaction system is not appropriate, energy is transferred through water or cold gases heat exchanger. No direct cooling water will be used. This eliminates the transfer of harmful pollutant from gases to water system from which it more difficult to remove. Mud recycling and recycling of scales is eliminated.

[0025] 2. Reducing Potentials.

[0026] At a particular temperature metal gets oxidized or its oxide get changed to metallic form if there are more oxidizing gases then an equilibrium value or conversely more reducing gases. This equilibrium value is a ratio between reducing and oxidizing gases where neither reduction nor oxidation of the metal takes place. These equilibrium values are calculated from the free energy relationship available in literature. In industrial systems usually there are mixers of CO, H2 and CO2, H2O, the potentials values are some approximations of the values of CO/CO2 and H2/H2O potentials.

[0027] Iron is reducible at chemical potentials easily achievable in practice. While copper oxide will change to metallic copper at very low chemical potentials not easily achievable. It will change to copper when heated in air at high temperature. Zinc oxide is reducible at very high temperature at achievable chemical potentials, but it will change back to oxide form as soon as temperature is lowered because corresponding reduction potential are not practically achievable. Sequence of reduction potentials of various metal oxides is as below.

Cu2O; Fe2O3→Fe3O4; NiO; SnO2; Fe3O4→FeO; P2O3; ZnO; Cr2O3; Mn O; Al2O3.

[0028] Gases reduction of chromium oxide and oxides after that is not possible even if very low contents of oxidizing gases are present. Certain metals will melt at low temperature when in reduced state (Cd melting point 765° C.), but its oxide will melt at considerably high temperature (CdO melting point 1540° C.)., Molybdenum (IV) oxide will become volatile at 1151° C. and one bar pressure.

[0029] Group of metals within certain range of chemical potentials may be reduced together and separated as a volatilized group or filtered out as a mixture of liquid metals. This is done to reduce the number of processing steps and number of reaction vessels. The recovered group is then separated into individual element outside the system. This is done by oxidizing the highest melting metal, skimming off its lighter oxide from the surface, lowering the temperature to the melting point of next metal forming the oxide and skimming off again and so on. This is called phase inversion method.

[0030] A group of certain metals may be reduced in a range of chemical potentials values but all of these metals are not easily meltable. These are usually soluble in a major constituent, which may take these out of the other charge material. The example is group of noble metal and platinum group metal which are separated by their solubility in copper.

[0031] Certain metals will go to the steel-making reactor in reduced or oxide form. The reduced metal will settle at the bottom of the reactor due to density reason (Pb, Au, Pt etc.) from where these are withdrawn separately.

[0032] A group of metals, which is not reducible by gaseous mixture (CaO, Al2O3, Cr2 O3, MnO, SiO2, etc.), will form slag. These can be separated into individual metal by treatment with Sodium carbonate. This is described under the topic of enrichment of silicate ores.

[0033] A group of metals become volatile and goes out with product gases is separated into individual elements by sequential condensation.

[0034] 3. Direct alloy steel production from mixed metallic ores.

[0035] Iron oxide is reducible in gaseous mixtures of CO/CO2 and H2/H2O. A part of CO, H2 gases introduced in the steel-making reactor is burnt with O2 to melt the pre-reduced Fe-FeO material and slag forming ingredients. From FeO to Al2 O3 as shown above, reduction of metal oxides become more and more difficult, requiring higher and higher reduction potentials until it is no more possible to reduce the metal oxides by gases alone. The criteria is that combustion reaction between the reducing gases and oxygen should provide enough negative free energy of formation that is more than the negative free energy of formation of that particular oxide under reduction and there should be sufficient remaining reducing gases in the system to carry out the reduction reaction to forward direction. Alternatively energy equivalent to the negative free energy of formation of the oxide under consideration should be supplied by some external source; that is by electrical heat or some exothermic reaction or temperature of the incoming gas streams or combination of these. Heat supply should be adequate that reaching to its melting point may decompose oxide.

[0036] Chromium oxide and most other alloying metals oxides are not reducible in gas reduction reactions alone, in generally achievable range of temperature 1650-1750° C. Cr, Mn, V and Ni all form homogeneous solutions with iron at all temperatures and in all proportions. W, Nb, Ti and other refractory metals form homogeneous solution in limited range but all get dissolved in iron in practical range of their utilization.

[0037] All these refractory metals form stable carbide with carbon at relatively lower temperatures. These carbide are soluble in liquid iron forming double carbide of the form (Fe-Cr.)xCy at their solidification temperature, but carbon is uniformly distributed at liquid temperatures where Fe and Cr are uniformly distributed. Some of the stable carbides of Chromium are given below.

1Compoundm. pt. C. °% CCr4C15205.46Cr7C17809.7Cr2C3189513.3

[0038] Chromium oxide is reduced by carbon at 1230 C. with heat of absorption according to the following reaction:

Cr2O3+C=3Cr+3CO ΔH=+ve

[0039] Stable carbides are also formed on reduction of chromium oxide with carbon at 1100° C. according to the following reaction.

Cr2O3+27/7C=2/7 Cr7C3+3CO

[0040] The reduction of wustite proceeds as following.

FeO+C=Fe+CO

[0041] Iron reduced from ore promotes the reduction of chrome, since chromium carbide which appears in the latter process dissolves in the iron with the formation of double carbide (Cr,Fe)7C. The melting point of commercial ferro-chrome is about 1500° C., in practical situations a temperature of 1650-1750° C. should be appropriate.

[0042] Some high melting refractory metals form carbides with high melting point but these carbides become soluble in iron at much lower temperature. Such carbides are of W, Mo, V, Nb and Ti metals. Manganese oxide although more stable than Chromium oxide behaves similar to chromium. NiO is very easily reducible oxide. The silicides of all the refractory metal and Fe are more stable than carbides. Thus alloying element is brought in iron solution by having more carbon in the liquid phase and particularly at the slag metal interface. When carbon and refractory metals are present C can be lowered to about 0.3%, below this refractory metals start oxidizing. Further lowering of C will require reduction in the partial pressure of oxygen. The next step is to eliminate this carbon down to very low values. Preferably this is done in a separate reactor other than where carbon-dissolving action was performed.

[0043] Blowing to final composition.

[0044] The conventional processes of alloy steel production namely VOD and AOD are modified that instead of vacuum oxygen degassing (VOD) and argon oxygen degassing (AOD) an appropriate mixture of CO2and O2 gases is blown through the melt. Carbon is eliminated through a combination of exothermic and endothermic reactions as following.

C+CO2=2CO endothermic or C+H2O=CO+H2 endothermic

C+O2=2CO exothermic H2+O2=H2O exothermic

[0045] The relative proportion of these two reactions can be controlled that no net temperature rise of the liquid steel takes place.

[0046] The CO gas formed is lead to cooling and heat recovery system and then passed through CO2 measuring system. This CO is passed through centrifugal exhaust pump to create high-pressure differential in the system. CO is then used for heat recovery. Some of alloying element would change to oxide by the elimination of carbon down to low values. This oxide is reverted back to liquid metal with the addition of reductants; namely ferro alloys, aluminum metal, silicon or others. Simultaneously flow rate is changed from CO2 and O2 to CO./H2 mixture.

[0047] Cr2O3+FeSi=2Cr+Fe+SiO2 exothermic.

[0048] Excess heat is available from the exothermic reaction which CO and H2 can utilize for the following reaction

Cr2O3+CO=Cr.+CO2 endothermic.

Cr2O3+H2=2Cr+H2O “

[0049] Excessive rise in temperature is not expected to take place, the amount of reductants used is decreased, with elimination of loss to refractory. This treatment helps to eliminate some of the volatile metals (Pb) under reduced partial pressure and high temperature and pressure differentials.

[0050] A process is invented for direct production of alloy steels from mixed ores of iron and alloying elements. Excess carbon is introduced to solubilise the alloying elements in iron, which is then eliminated by blowing CO2 and O2 of specific composition simultaneously keeping the temperature of liquid metal as desired. The temperature of out going gases is lowered and suction is applied. This volatilizes certain metals normally not required in steel. Oxidized alloying elements are recovered back to liquid steel with the addition of deoxidant/reductants with simultaneous blowing of CO, H2 mixture which will partially reduce the oxidized alloying elements. When It is desired to remove O2 from steel a mixture of CO2 and C (CH4) is made to blow in the liquid phase. The composition of CO2 and CH4 adjusted to achieve a desired temperature of the bath.

[0051] 4. Sulfur recovery from high contents SO2 containing gases.

[0052] Sulfur recovery as elemental sulfur can be done in a more direct way as given in the following than the conventional Claus process:

2CH4+3SO2=2 CO2+2 H2O+H2S+S

2H2S+SO2=2H2O+3S

2CH4+4 SO2=4 H2O+2 CO2+4 S ΔH=−58,000 K. cal./Kg. mole of CH4

[0053] The S is cooled and condensed and product gases are send for further purification from particles and chemical impurities alone or joined with other gaseous streams.

[0054] A sulfide roasting reaction is highly exothermic. Conventionally to control the development of high temperature water is introduced and air is the gas used for oxidizing roasting. The product gases obtained become dilute in SO2. If roasting reaction is carried by oxygen and heat of roasting reaction is removed by carrying out indirect endothermic reaction in the same vessel, directly usable concentrated SO2 is obtained. Energy of roasting can be taken to heat recovery boilers by product gases of the endothermic reaction. (CO2+CH4→CO+H2). As a result of the roasting reaction mixed oxides are obtained which can be processed in the same manner as low quality scrap.

[0055] 5. Use of oxygen for exothermic reactions

[0056] All energy generation reactions during steel making and calcing of flux are performed with the combustion of oxidizing gases. By using O2 in close systems all CO, H2 gases are recycled for energy generation. The energy efficiency of the fuels is 100% as compared to present systems where energy recovery is hardly more than 55.0%. This recycling compensate expenditure on oxygen generation. As the fuel expenditure is decreased so the emission of CO2 is decreased. Some of the CO2 is recycled within the plant for energy recovery purpose; thus emission of CO2 is further decreased.

[0057] The cold values in the gases nitrogen and oxygen can be recovered and can be used for plant cold requirement in air conditioning and other cooling purposes. This way high cost of oxygen generation can be curtailed considerably. Nitrogen along with CO2 and SO2 from the plant is used as fertilizer gases.

[0058] 6. Direct use of fines containing material.

[0059] At the beginning of this disclosure direct use of finely crushed raw material (ores, coal, and flux) was mentioned. This material is introduced in a high temperature reactor were high temperature is produced by the introduction of oxidizing gases. The temperature of the reactor is raised above the melting point of most of the charge ingredients introduced in this reactor. Thus every thing is smelted (including the coal ash) and joins the liquid phase. Minimum of the charge is allowed to go with the product gases. This is due to specific design that gases become stagnant or lose their blow out force for a little time when settling due to density differential take place. Impurities in the charge like C, S, P and N2 go out before coming in contact with liquid steel forming ingredients. Any additional C or O2 required in the melt is introduced under the slag phase. Carbon required for reduction of alloying elements into steel is introduced this way. The gases, which are made to exit from the side of the reactor, are lowered in temperature by the introduction of endothermic gases. The temperature of the exit gases is 1000-1100 C. These exit gases are further lowered in temperature by passing them through heat exchangers. Sequential condensing of volatile metals is performed and blown out charge is retained.

[0060] Steel produced may go direct to a casting tundish or composition adjustment reactor, depending upon the composition of steel. A plain carbon or low alloy steel where additional alloying elements are not required will go to casting directly. In endothermic type of casting system, some additional C, O, S, P and volatile may be eliminated along with exit gases. When alloying additions are required for composition adjustment and amount of C, O, S, P to be eliminated is high (>0.3%), steel from steel making reactor may go to composition adjustment reactor.

[0061] Describing briefly the following has been disclosed.

[0062] Use of endothermic reactions for lowering materials temperature and use of product gases from endothermic reaction for heat recovery purpose.

[0063] Heat recovery by use of water and cold gases through heat exchangers.

[0064] Use of controlled chemical potentials for separation of metals from combined mixtures like scrap.

[0065] The preparation of alloys from mixed oxide ore by first introduction of some reductant (C) and then eliminating that. Also eliminating excess C,O and fine adjustment of prepared steel composition.

[0066] The recovery of cold values from nitrogen and oxygen from air fractionation plant and use of product gases for fertilizer gases.

[0067] It is purpose of this invention to provide processes and equipment which can use various iron bearing materials namely oxide ores alone or mixed with alloying elements ores, processed steel scrap and sulfide ores. Processed iron and alloying metal oxides may be obtained from mixed charge of iron aluminum silicate ores and refractory metal oxides. Finished products are steels, micro-alloy steels, low alloy steels and high alloy steels. Hydrocarbon fuels, flux, oxygen or oxygen enriched gases are other charge materials.

[0068] It is also purpose of this invention to provide direct and shorter process routes and reaction periods, with no pollution to the environment and minimum of energy consumption, high degree of energy recovery, simplicity of design and modern means of controls. The invention will incorporate best modes to carry forward the steel making and steel shaping process with elimination of impurities, volatile and structural defects.

[0069] There may be two or three main process set- ups from start of steel-making to finished products; depending on the type of steel produced.. Processes can be operated and controlled independently, their operational timings are arranged that with normal repair hold ups in the processes, the main process remains continuous. Various best modes process may be as below:

[0070] Best mode to perform a pretreatment on charge of iron and alloying elements ,coal and flux before their introduction into a steel making reactor comprises the steps of:

[0071] Introducing the charge through a double locking device near the upper ending of a reactors system. It is made to move along the inclined reactors and oxidizing gases are introduces in the reactors system at stationary parts. The charge may be preheated and partially reduced.

[0072] The primary reactor may have moving and stationary parts. Stationery parts being between the moving parts. Last stationary part is having an exit connected to an inlet of a steel making reactor. In a preferred arrangement the stationary parts may be made vertical between the inclined rotating parts. The inter-reactor separation arrangements are placed in the vertical parts. The rotating parts provide forward movement to the charge.

[0073] When there is meltable material to be separated the rotating reactors are made stationary and stationary parts have porous refractory bottoms and refractory chambers for collection of melts. The forward movement is assisted by external means.

[0074] The charge may be a mix of steel scrap and coal from which elements not required in steel and steel alloys composition are separated and recovered. Best mode operation may comprise the steps of:

[0075] Introducing the charge into an inlet end of a primary reactor of a reactors system having an inlet end and an outlet end while injecting oxygen into said primary reactor near said inlet end and passing the charge through said primary reactor to said outlet end thereof:

[0076] Discharging said charge through a sealed connection into an inlet end of a next reactor for increasing the temperature and changing the chemical potential of said next reactor having an inlet and out let end and passing said charge through said next reactor. Number of unit operations performed in the separation of non required ingredients depend upon the number of elements, their melting and boiling points, and chemical potentials at which phase change may take place.

[0077] Ingredients whose melting points or volatilizing point and chemical potentials for phase change are closer together will form a group, one group is processed in one of above said reactors, ingredients separated as a melted group and volatile group are separated out side the system by fractional condensation of volatile and phase separation for liquids.

[0078] Several unit operations form one single unit process; unit processes are separated from each other and have independent means of input and outputs, control of chemical potentials and temperatures.

[0079] Unit processes have means to transfer of-gases and material from one unit -process to the next, volatile exiting from each unit process are made free of condensable material and there after sent to particles recovery and removal of chemical impurities from gases. Several gaseous streams exiting from different unit processes are combined and combined gases go to particles and impurities removal.

[0080] Recovered blown out charge particles are recycled to the above said primary reactor. and recovered clean gases are recycled for various uses. The charge purified from most of impurity ingredients is discharged from an ending reactor of the above said reactors system having out let connected with a steel making reactor through above said sealed connection or directly.

[0081] For ease of operation first reactor is operated upto about 1000° C. and chemical potential reducing up to PbO and GeO2, the energy is created by combustion of reductants with oxidants. The volatilised metal up to this temperature are Te, Cd, Se, As, Hg. These are separated in a fractionating arrangement, which is divided in to various chambers. Circulating cooling media is passed through vessels made of double shell molybdenum cladded inside with graphite. From the bottom of this chamber the particularly solidified metal is drawn out. After volatilized metals removal the gases go to particles recovery units. The recovered particles are recycled to the beginning of this reactor. The liquid metals filtered out from this reactor are collected together and then separated to individual element by phase separation method.

[0082] Oxidizing gases are passed through the metals solution; the oxide phase stable at this temperature will float on the surface and is skimmed off. The temperature is lowered and oxidizing gases are passed through the next melt solution and oxide stable at this temperature is skimmed off. The sequence of metals oxide separation will be: Sn O (1600° C.), PbO (886° C.), Bi2O3(825° C.), Te2O3 (717° C.), Sb2 O3 (650° C.), In O2 (562° C.), GAO (500° C.)

[0083] This charge is then moved to the next reactor, where the temperature is between 1050 to 1300° C., the chemical potential in this reactor is mildly reducing or oxidizing. The metal filtered out in this reactor are Cu, Noble metals, Platinum group metals and metal which were not removed in the previous reactor. These are collected together and the previous group metal are separated be phase separation. The Cu and metals soluble in copper, which are not oxidized, are cast in to anodes and then separated into individual elements by conventional means. In this reactor oxidizing gases flow counter current to the melted charge.

[0084] Following is a best mode for steel making from sulfide ores whose composition is similar to low quality scrap. Steel scrap or its replacement obtained from sulfide ores may be used for the preparation of micro alloy steel. The slag obtained from this process is best used as micro nutrient fertilizer.

[0085] It may be pointed out that in the above mentioned separation, small percentage of trump elements remain and go to the final melt of steel. This steel is a micro alloy steel produced directly or with the addition of some additional component. Treated sulfide ore may be a source of micro alloy steel.

[0086] In parallel to the scrap composition some of the sulfide ores contain large number of ingredients only some of these are presently recovered.

[0087] Taking the example of zinc blende the most important ore of zinc sulfide usually contains Zn, Fe, Pb, Cd, Mn, Cu, As, Sn, Bi, Co, Hg, In, Ga, Ag, Au, and slag forming ingredients. These sulfide ores are given an oxidation- roasting step to remove and recover SO2 in concentrated form. This SO2 can be treated for recovery of elemental sulfur or SO2 may be used in the fertilizer products

[0088] The vaporizing temperature and sequence of metal oxides vaporized is different than in reducing roasting After SO2 removal the gaseous stream is sent for further treatment for particles removal and elimination of chemical impurities. A preferred embodiment of this process for obtaining a charge for steel making may comprise the steps of:

[0089] Introducing a mix of sulfide ore and coal in a refractory lined reactor having a locked in put means, near its upper end. It has outlets for solid products and volatile containing out going gases. Oxygen is introduced near the above said charge inlet. The above said reactor is having an inner reactor packed with catalyst and having inlet means for endothermic gases and outlet means for reformed gases. When the sulfide is being given a roasting treatment with O2 and heat of exothermic reaction is absorbed by performing indirect endothermic reaction within the same vessel. The volatile gases are led out the reaction system and concentrated SO2 and volatile elements are recovered before sending the gases to particles recovery and separation of chemical impurities. The oxides of the metals so formed are processed similar to scrap as in above embodiment.

[0090] Some of the metals whose oxide decompose at temperature up to 1000° C., and metals are melted, are filtered out. Other metals which form more stable oxides, are given a reducing treatment in the next reactor to volatilize Cd and filter out metallic Sn and Ge along with metals which were not separated completely in the previous reactor.

[0091] To separate Cu and its allied metals from sulfide concentrates the gaseous atmosphere is made oxidizing to all the metals and temperature is above 1250° C. The oxides of copper and its allied metal (Noble metals, Pt. group metals) are not stable at this temperature. Other metals form stable oxides NiO, melting point 1930° C. and Fe3O4 melting point 1650° C. with much lower densities than Cu and will float on the surface of liquid Cu. The Cu and metals miscible with it will be filtered out in a counter current stream of oxidizing gases.

[0092] In next reactor the chemical potential is made reducing to Ni (melting point 1435° C.) but still oxidizing to Fe, hence Ni and its miscible metals are filtered out. The rest of the material goes to steel making reactor where steel is produced directly and adjusted to adequate composition in secondary steel making process.

[0093] The best representation consist of introducing concentrates of mixed sulfide ores mixed with some high temperature melting slag ingredients and are charged to the fist reactor through double locking system. The refractory lined steel shell has its lower portion made of porous material through which liquid metal can filtrate against rising oxidizing gases.

[0094] O2 is also introduced near the upper end of the first reactor. The high exothermic heat of sulfide roasting to oxide is controlled by exothermic reaction performed in a closed vessel inside this reactor. The exit gases are freed from volatile and SO2. Sulfur dioxide may be directly used as fertilizer combined with plant nitrogen and piped to the surrounding areas as substitute for ammonium sulfate. SO2 may be used as anti fungus agent.

[0095] Cu and Cu miscible elements are separated in this reactor, and then the charge is pushed to next reactor by a water-cooled mixer plus pusher. The chemical potential and temperature of this reactor is raised so that Ni and miscible elements are filtered out against a rising gas composition reducing to Ni and oxidizing to Iron. The separated material at 1435° C. may contain small percentage of Cu and Fe and Co. This charge is granulated with water jets and then sent for processing by carbonyl fractionation.

[0096] The charge is then pushed to next reactor where alloy steel can be produced directly and the gases are sent for particulate recover and final purification.

[0097] Recovery of refractory metals oxides, alumina and Fe3 O4 from a mixed charge of refractory metal ores and iron aluminum silicate ores.

[0098] Best mode for separation of refractory metals oxides, silica, alumna and iron oxide, is achieved with flux of Na2 CO3 and comprises the steps of:

[0099] Introducing the preheated charge of above material in a high temperature reactor along with sodium carbonate. Sodium salts formation in this reactor takes place in temperature range of 1000-1300° C. in an oxidizing atmosphere.

[0100] Sodium salts formed are separated by their density differential. Low density liquid slag material is allowed to flow out as upper layer and heavy density solid material is withdrawn from the bottom of the reactor.

[0101] From high density material FeO-Fe3 O4 is separated by magnetic means. Sodium salts are changed to Na2 CO3 by blowing through CO2. Sodium Carbonate is recovered and recycled. Iron oxides so obtained is mixed with refractory oxides recovered in alloying ratios and charge is processed for various alloys production. The material to be separated is preheated in the reactor system and top gases are freed of particulate and chemical impurities and the CO, H2 and CO2 produced are recycled to the separation reactors system. In a high temperature reactor Na2 CO3 is added, and sodium salts formation is carried out. Low-density slag formation (density value around 2.5-2.7-gm/cu. cm.) will take place for the following metals.

Na2 CO3+Si O2=Na2Si O3+CO2

Na2 CO3+2Cr2O3=Na2Cr2O4+C O2

[0102] Na2Mo2 O4, Na2 V2O4 and CaO will be also present. Some Ca Si O3 and CaWO4 will be formed. The high-density material containing the following (density values around 4.9 gm/cu. cm.) ingredient will be formed and will settle on the bottom.

Na2CO3+Al2O3=Na Al O2+CO2

FeO+CO2=Fe3O4

[0103] CaWO4, Na2W O4 and Na2Nb O4 are high density oxides and these will also settle at the bottom. The slag material is continuously separated from an upper level slag notch, and high-density material is drawn out by water-cooled screw arrangement. These two types of materials are then separated further.

[0104] A process for the manufacturing of steel and steel-alloys, where in the best mode for carrying out this invention comprises the steps of:

[0105] Introducing a prepared charge of iron and alloying element, coal and flux into steel making reactor; wherein oxidizing and reducing gases and their combinations are also introduced above and below a slag layer. The out-put from this reactor may be steel, micro alloy steel or high alloy steel depending upon the composition of prepared charge and composition of the blown in gases.

[0106] Excess carbon is introduced to solubilise the alloying elements in iron. After achieving required solubility this excess carbon is removed in the same reactor where some carbon may remain or the liquid is over blown and has some excess oxygen and oxides

[0107] Plain carbon steel produced in the process may directly go to steel casting process. Alloy steels may undergo secondary steel making operation for final adjustments in its composition, both of these processes make some composition adjustment of the steels. A best mode of carrying out this innovation is that all steel go through a composition adjustment operation (secondary steel making) Slag may go to heat recovery process.

[0108] Steel-making reactors may have refractory cooling arrangements by endothermic means. Exit gases from steel making reactor are lowered in temperature by introduction of endothermic gases in the gaseous stream.

[0109] A best embodiment for the heat recovery from slag may comprises the steps of:

[0110] Blowing a ( CH4+CO2) mixture through film or micro-drops of slag. The reformed gases produced thereof are sent for energy recovery.

[0111] The best mode for carrying out the composition adjustment of steel alloys produced may comprises the steps of:

[0112] Eliminating excess carbon by blowing CO2 and O2 of specific composition, where after oxidized alloying elements are recovered back to the liquid steel with the addition of deoxidant/reductants with simultaneous blowing of CO.H2 mixture.

[0113] Excess O2 from steel may be removed by blowing a mixer of CO2 and CH4, the composition of CO2 and CH4 is adjusted to achieve a desired temperature of the bath.

[0114] A preferred embodiment for gas purification process for product gases obtained from steel making process will comprises the steps of:

[0115] Off gases from steel making operation may flow directly out of steel making reactor. Temperature of out going gases is made to decrease by performing endothermic reaction with direct contact with these gases. These off gases may be led out, for recovery of volatile elements, energy and blown out charge particles and after these gases go to cleaning from chemical impurities

[0116] The best mode of removing the chemical impurities from exit gases is:

[0117] During the chemical impurities removal steps, sulfur containing gases are removed before the CO2 removal. Where desorption of CO2 from the solution is made by heat energy contained in the impure gaseous stream, Energy spent in the compression of gases and solutions is regained by expansion of gases and liquids. Clean gases CO,H2 and CO2 obtained are recycled for uses in the steel making and auxiliary operations.

[0118] A process for the shaping of steel, in which best mode for carrying out the invention comprises the steps of:

[0119] Heat is recovered from liquid steel by performing endothermic reaction in direct contact with the liquid materials. To create an intimate contact between liquid and gases, the liquid is given the shape of small droplets or thin liquid film or a combination of both. Exit gases after performing endothermic reactions are led to combustion process for steam generation.

[0120] Endothermic reaction is performed in a refractory lined steel chamber; with controlled entry and exit of reactant and product gases. During cooling process the solidifying steel is given an appropriate form; flat, shape of near net shape castings in a mold of appropriate dimensions. The mold is a steel shell internally lined with porous refractory, the refractory is endothermically cooled.

[0121] Steel is taken up by withdrawing rolls as it exits from the mold, and it is rolled in a tunnel having protective atmosphere of gases. During solidification and rolling processes the surface and interior temperature is kept same and entrapped gases continue to diffuse out as the temperature of the material is lowered.

[0122] During solidification and rolling, material is compressed by internally cooled chromium steel lined rolls. Additional heat balancing arrangements are provided for controlled cooling of solidifying steel strand. The exit gases from endothermic chamber are given a rapid pressure gradient, first by lowering their temperature by further injection of CH4+CO2 and then by performing shift reaction over a catalyst, condensing out water vapors contained in these and then by an exhausting fan. These gases may go for energy recovery.

[0123] CO/CO2 gases are used as protective gases against oxidation of the steel strand in refractory lined protective tunnel. CO/CO2 mixture may be produced by reacting CO2 with sulfur free coke or anthracite.

[0124] The material starts solidifying from multi points in the interior of the specimen as well as from the surface. Formation of small drops during solidification process and high temperature exhaust gradient provide facilities for the volatile and impurity element like C, O, S, P and metallic volatile to escape.

[0125] Steels are shaped under protective atmosphere, the best mode of carrying this invention may comprise the steps of:

[0126] Gradually lowering the surface temperature in a protective atmosphere so that inside gases can diffuse out, shapes with sharp corners can be casted and small size casting with corner can be made. The protective atmosphere of CO/CO2 will drive out H2 by the following law of mass action and chemical shift equilibrium reactions.

CO+CO2+H2=2CO+H2O

[0127] In this system re-heating furnaces and water sprays are eliminated. A very important advantage is elimination of pickling before going to cold rolling. Picking action is very detrimental to steel properties. Hydrogen attack on grain boundaries and anode reaction weakens the steel material and hydrogen is diffused in the steel. By eliminating scale formation, the surface cleaning by pickling is eliminated and also is eliminated acid waste problem, electrolytic washing, rinsing drying and welding. It becomes possible from hot rolling to go directly to cold rolling on the same line.

[0128] Protective atmosphere in the tunnel is provided by CO/CO2 mixtures which are not oxidizing to steel at the rolling temperatures under practice. Strand is made to exit through an atmosphere controlling exit gate. This gate has a slit of approximately of the same dimensions as the rolled shape or flat. Steel strand pass through the slit but the flow of gases is blocked. Similar gates are at the ending and start of the tunnel where gaps are created in the continuity of the tunnel.

[0129] Protective atmosphere within the tunnel is maintained by means of sliding and rotating seals around the rolls. Coolant for the internal cooling of the rolls can be introduced and made to exit.

[0130] A steel shaping process in which the best mode of carrying this invention is through the steps of:

[0131] There being a opening in the tunnel after which a continuous finishing train starts. Continuous finishing train operation is carried under appropriate reduction potential and temperature, both of these may be varied depending on the type of steel being rolled. After the continuous rolling train there is another open section for measurements and control.

[0132] Where after this open section the surface finishing process starts. Surface finishing is started around the upper critical temperature of the steel and is continued to a little lower than lower critical temperature.

[0133] Rolling process is continuous in line for the strip but is not in line for the shaped products. For the shaped product an appropriate length of the shape is cut and shape is pushed to a side chamber. In these chambers temperatures and chemical potentials can be maintained as required. In which steel is rolled and then under goes similar repeats required for the finishing dimensions with lowering of rolling temperature. In which end product of the shaped material is controlled tempered at 100-200° C. for a time period depending on the dimensions and composition of steel.

[0134] Strip products; after in line surface treatment is taken out to a lower elevation for winding purpose. Coiled strip is tempered at 100-200° C. for 1-2 hours depending on the thickness and chemical composition of the strip.

[0135] A process for the cold rolling of steel where Steel is to be finished in cold rolled condition and subsequently annealed and temper rolled. Best mode of carrying this invention may comprises the steps of:

[0136] Surface finishing treatment after hot rolling is omitted and steel is further cooled to ambient temperature and goes directly to continuous train of cold rolling stands. Steel may go to in line continuous annealing process.

[0137] Annealing is done under controlled temperatures and chemical potentials of each section according to the requirements of steel compositions. Annealing is done in an atmosphere of H2, in which CO and N2 can be made variable. After cold rolling, the coil enters the continuous annealing section, where it is heated to about 750° C. It passes through controlled atmosphere regions; first through oxidizing gases and then through reducing gases. It is given a temper rolling after appropriate cooling. Annealing treatment is parallel for flats and shapes with changes in mechanical configuration

[0138] A rolling process without protective seals around the rolls. Best mode for carrying this invention may be as following.

[0139] The tunnel can end just before and after the rolls and strand passes through the slits of atmosphere protecting gates Tunnels have such gates at both the ending, and desired atmosphere can be kept within the tunnels. Reducing gases can blown below and above the strand and before and after the rolls The gases are sucked and carried for energy recovery. An air fractionation process for production of O2 and N2 gases for use in steel and steel alloys making process, the gases products from this plant has the following best mode of utilization:

[0140] Using cold O2 and N2 cold gases are produced. Along the N2 line there are CO2, and SO2 lines carrying gases to fields. Nitrogen may be used as fertilizer as a replacement of ammonia. Nitrogen pipeline is buried a short distance below the plowing level in the fields. Soil over the buried nitrogen pipes is mixed with bacterial clay consisting of animal and human excretion and decomposed vegetation growth. Mixer of CO2 and N2 may be used as substitute of urea.

[0141] Thermal power plant and electricity generation.

[0142] With small additional consumption of natural gas the energy carrier gases from various units may be able to produce enough electricity to meet most of mill's top priority consumers. Energy sources are given in the following (1) Excess clean gases from steel-making reactor and lime calcination plant (2).Exit gases from steel solidification system ( 3). Exit gases from slag cooling (4). Exit gases from steel rolling tunnel. (5). Off gases from secondary steel making reactor (6) Off gases from CO generation system (7).Off gases from annealing process.

[0143] These inventions could have been easily understood by description of embodiments there-of with reference to the attached drawings 1-12.

[0144]
FIG. 1 shows a preliminary reactor for the treatment of iron ores, or iron ore mixed with oxide ores where no meltable elements are to be separated.

[0145] For charge of FIG. 1 no treatment is done to these ores except mixing ores in appropriate ratios and removing over size material and crushing it for remixing. This charge with solid reductant (0-6mm) and flux is introduced to a rotary reactor a short distance down from its upper ending at 1 in FIG. 1. Oxidizing gas 2 is also introduced at this ending. The lower outlet of this reactor is joined to an inlet of a steel making reactor, 31. This inclined reactor has rotating and stationery parts joined together with pressure tight rotating seals, 23, reactor being made of a steel shell lined with refractory 3; The refractory being covered with heat resistant high temperature steel liners which could be replaced,4 . The rotary portion of the reactor has lifting baffles. These baffles are also covered with liners and have cooling plates embedded in the baffles but extruding out the cylinder shell 8. Cold air from external nozzles goes inside the plate openings and keeps these cool. The rotating seals have flanges attached to the stationary and rotating cylinders In between these flanges is a skirt spring held fixed on stationary flange on one end, its other end is pressing forcefully against rotating flange. The space between skirt and rotating cylinders is filled with refractory wool and may be internally and externally cooled. At the upper ending of the steel-making reactor is a blow off safety valve, 7. The speed of rotating parts of the inclined reactor determines the movement of charge.

[0146]
FIGS. 2A, B shows the best mode of the production of steels and steel alloys charge from steel scrap, the preliminary reactor has been changed into cascade configuration.

[0147] The sized charge material is charged to an inclined reactor 1, where it can be turned by mechanical means2, and give a slight push to move charge along the reactor. The gaseous potential in this reactor is reduction to a group of metal, that can melt or volatilized up to a temperature of 1000° C. The volatilized metals 3 and metal melted 4 in this range are shown in the FIG. 2.A. All easily meltable metals 4 are filtered out together 5, as these are miscible in all proportion. The volatile group is Hg, Se, As, Cd, Te; WO2 and these are separable by fractional condensation in reducing and oxidizing atmospheres. Melted metals are then separated by phase separation means as shown in figure FIG. 2.B. The sequence of separation under oxidation potentials and controlled temperatures is shown in FIG. 2B no 6. The density of metal oxide is lower than metallic liquid, is skimmed of The sequence of separation is GaO, InO2, GeO, Sb2 O3, Tl2 O3, Bi2 O3, Pb O, Sn O. The sequence of separation of volatilised metals is also shown on this FIG. 2.B.

[0148] The next separable group is in the range of 1000-1250° C. It may contain Cu, Noble metal, Pt. group of metals 7 and some metals not separated in the previous reactor 1 . Pt. group metals are not meltable in this temperature range but get separated due to their solubility in Cu and noble elements. Mo O2 if formed by gaseous reduction will be volatilized at 1300° C.

[0149] The Cu containing metal group is separated from previous group metals by phase separation. Cu, noble metals, Pt. group metal are separated by electrolysis and then by conventional techniques. The gas flow here is co- current and rest of the material is charged to a final reactor 31 which is steel making reactor. The material is melted here in temperature range 1650-1750° C. and exit gases are treated for the recovery of Zn and Pb, and further for any remaining volatile metals. From the melt in reactor 31 are separated Pt. group metals and Pb from the bottom, micro alloyed steel 10 and slag 11 from the sides. Some fluxes and C may be introduced in this reactor 13.

[0150] Zinc will be oxidized back to zinc oxide during its condensing and float on the surface of other metals from where it can be separated and then converted to metal zinc in a separate system in complete reducing system and condensed under protective atmosphere. The temperature of the hot gases is first lowered by endothermic reaction and then by heat exchanger system. The gases are then sent for further gas cleaning and recycling, alone or combined with other streams.

[0151]
FIG. 2.C,D. Steel making from sulfide ores. C, whose composition is similar to low quality scrap. D, sulfides from Cu, Ni flotation process.

[0152] These sulfide ores are given an oxidizing roasting step 3 to remove and recover SO2 in concentrated form FIG. 2.C,D. This SO2 can be treated for recovery of elemental sulfur or SO2 is used in the fertilizer products system. During this oxidizing roasting some of the metal oxide, whose oxide are stable and become volatile at the roasting temperature, will go out with SO2 These are shown in 5. in FIG. 2C.

[0153] The vapouring temperature and sequence of metal oxides vaporized is different than in reducing roasting 5. After SO2 removal the gaseous stream is sent for further treatment for particles removal and elimination of chemical impurities as described previously 7. Some of the metals whose oxides are decomposed up to 1000° C. are filtered out 8. Other metals, which form more stable oxides 9 are given a reducing treatment in the next reactor to volatilize Cd and filter out metallic Sn and Ge and some metal not separated completely in oxidizing roasting. Further treatment is similar to FIG. 2. for scrap treatment.

[0154]
FIG. 2D explain production of Cu, Ni and Steel from complex sulfide ores.

[0155] Concentrates of mixed sulfide ores are mixed with some high temperature melt forming slag ingredients, are charged to the fist reactor through double locking system-1. FIG. 2D The refractory lined steel shell has its lower portion made of porous material through which liquid metal can filtrate against rising oxidizing gases 5. O2 is also introduced through the upper end of the reactor 3. The high exothermic heat of sulfide roasting to oxide is controlled by exothermic reaction performed in close vessel 9. The exit gases are freed from volatile and SO2. Sulfur dioxide may be directly used as fertilizer combined with plant nitrogen and piped to the surrounding areas as substitute for ammonium sulfate. Cu and Cu miscible elements are separated in this reactor 14 and then the charge is pushed to next reactor by a water-cooled mixer plus pusher. The chemical potential and temperature of this reactor is raised so that Ni and miscible elements are filtered out against a rising gases composition reducing to Ni and oxidizing to Iron 16. Copper processing reactor is isolated from nickel processing reactor by a water-cooled double lock 15. The separated material at 1435° C. may contain small percentage of Cu and Fe and Co. 17 This charge is granulated with water jets and then sent for processing by carbonyl fractionation. The charge is then pushed to next reactor where alloy steel can be produced directly and the gases are sent for particulate recovery and final purification.

[0156]
FIG. 3. shows the preferred mode of recovering refractory metals, alumina and Fe3 O4.

[0157] From mixed slag and ores.

[0158] The material to be separated is preheated in the reactor system and top gases are freed of particulate and chemical impurities and the CO, H2 and CO2 produced are recycled to the reactors system.33 where Na2 CO3 2 is added in reactor 51. The sodium salts formation is carried out in an oxidizing atmosphere in a temperature range of 1100-1300° C.

[0159] Following explanation applies to FIG. 3.

[0160]

1
Scrap residue plus low quality ores plus coal. 3 Oxygen. 5 Na2 CO3 .7 Heating under oxidizing conditions. 9 Extrusion of Na Al O2, Fe3 l O4, Na2W O4, and Na2 Nb O4. 11 Addition of CaO to contents of 9. 13 Cooling of charge of 9. 15 Dissolving in water and separation of residue Fe3 O4, Na2W O4, Na2Nb O4. 19 magnetic separation of Fe3O4. 21 Recovery of tungsten oxide and niobium oxide. 23 Solution of Na Al O2.25 Recovery of Al (OH)3 by CO2 blowing. 27, 29, 31 recovery of alumina. 33 Slag cooling. 35 slag dissolving in water and blowing of CO2 for recovery of sodium carbonate. 39, 41 Concentration and drying of sodium carbonate and cycling back to the reactor. 43,45,47 blown out particles recovery, gas cleaning and recycling of cleaned gases.

[0161] Best mode of preparation of steel and steel alloys from prepared charge is explained in FIG. 4.A,B,C,D. An over all schematic diagram is shown in FIG. 4.A.Charge is introduced at 1 into reactor 3 to steel making reactor 31 The clean gases and oxygen is introduced into steel making reactor 5, 6, 21. The flow rate, pressure and temperature of clean gases and O2 can be varied to melt the charge and burn out all carbon and sulfur in the charge. Details of steel making reactor are shown in FIG. 4.B. It has embedded endothermic cooling plates 34 and detachable bottom 35, and porous plug inlet tuyeres 21.

[0162] Various input output streams are configured around a high temperature reactor 31 having a co-current gases solid input. The input streams are given specific pretreatment or nun accorded to the products to be obtained and ingredients to be removed. The out put streams from the reactor go for identical treatments, namely endothermic cooling of hot stream, recovery of volatile and blown out charge. Heat is recovered from hot streams gases, slag and liquid steel. This reactor has operational aid attachments, such as sample withdrawal, blow in attachments, controlled discharging devices and cooling of refractories. A special construction feature of this reactor is that out going gases are withdraw a small distance above slag layer. The flow pattern becomes stagnant for a little while and metallic particles settle down, while all gases go out carrying their impurity ingredient. There is a sample hole above the tuyere level to draw samples of liquid steel and slag 27 This is explained in more detail in FIG. 4.C. Porous plug tuyeres are explained FIG. 4.D Both slag 9 and steel 10 are withdrawn from the sides of the reactor 31 figure FIG. 4A where slag goes to a heat recovery and fiber formation FIG. 5. and steel is discharged to a refractory lined rotating reactor 5F for precise composition adjustment.

[0163] Heat recovery and fabrillation of liquid slag FIG. 5.

[0164] Slag can be transformed into fibrous material as slag wool or further crushed to form small fibers. The small fibers can be an alternative of gypsum in light weight cement products. 51 is the slag discharge to a slag ladle, from which it is pored at controlled rate 53 to rotating cylinders 55 the endothermic gaseous mixture 7 ( CH4+CO2) is blown counter-current the slag film or particles. The gate valves 61, 63 of the fibrillation chambers 59 work on alliterative sequence. The product gases( CO+H2) formed go to energy recovery system Energy is recovered by reaction gases by cooling the slag from approx. 1550° C. to 850° C. and then through water heat exchangers from 850 to 300° C. Slag is further cooled on conveyor by cold air.

[0165] Steel produced in processing scheme described above, may be directly taken to the tundish of a continuous casting rolling process. But to have an addition degree of processing freedom steel is discharge to a rotate-able reactor FIG. 6 in which composition of the steel may be freed of C and other impurities, steel composition may be precisely adjusted and alloying additions can be made. This vessel can serve as a carrying vessel and a teeming ladle. Providing mobility to the vessel mean adequate layout can be provided. A preferred arrangement of this reactor is given in FIG. 6.

[0166]
FIG. 6. Adjustment of steel alloys composition

[0167] Steel is introduced 1 in a refractory lined reactor which can be rotated about its central axis and is placed on remote controlled railway trolley. Gases Like CH4, CO2, CO, O2 2,3 can be blown into this reactor through tuyeres. The off gases are taken out through 4 to gases cooling, CO2 measurement and an exhaust system is applied to exit gases. Finished steel is poured through 5 to steel casting tundish. Alloys addition is made through a double locking device 6.

[0168] A best mode for carrying out the gases purification from particles and chemical impurities is given in FIG. 7.

[0169] From the blown out charge material of the reactor system, first the volatilized metal are recovered, then SO2 is recovered as elemental sulfur or concentrated SO2 gas. The gases after this treatment may contain blown out particles, H2S— SO2, CO— CO2, H2—H2O and some N2 and CH4, trace amount of other gases. The following scheme will describe how to remove the particulate, the impurity gases H2S, SO2, CO2, the condensable H2O and keep the amount of N2 constant is the cyclic gas system. The particulate recovery system consists of a blown out particle collector where the particles are settled by gravity forces and decrease in gas temperature. Energy may be recovered in this vessel by heat exchange means, and particles are discharged through screw extruders. The particles are further removed, by filtering the gases through bag filters. There are two bag houses working in alternative. The bags are made from glass cloth with working temperature up to 500° C. The gases are finally purified by passing through electro -static-precipitator with working temperature up to 500° C. The recovered particles are discharged through screw extruder and are joined to discharge from the first particle recovery vessel. This combined discharge is recycle back to the reactors system; the position of re-introduction depends on the nature of the charge.

[0170] If it has volatilized material, it is reintroduced into the vessel from where it volatilized. If it is blown out charge without volatile it is reintroduced in the steel- making vessel. The first particles recovery vessel, the bag houses the electrostatic filter, are all refractory lined vessels capable of working up to gases temperature upto 500° C. The energy contained in these gases should be adequate to satisfy the energy need of the gas purification from chemical impurities.

[0171] Gases cleaning of chemical impurities.

[0172] Following Nos. explain the working of FIG. 6.

[0173]

1
Absorption column for CO2. 2 Energy recovery from clean exit gases. 3 Water vapor condensation from clean gases, and recycle of condensed vapors. 5 Recycling of lean solution. 9 Make up solution of K2CO3 and corrosion inhibitor. 13 Filtration of K2CO3. 20 Stripper column. 21. Hot gases from electro static precipitator. 23 Heat exchanger for heat recovery from hot gases. 25 CO2 exhaust, water vapor recovery and recycle of recovered water. 27 Entry of hot expanded liquid. 29 Heating the solution for vaporizing of CO2. 31 Heat exchanger for cooling of lean solution. 33 Pump for liquid compression and entry to absorber column. 35 Drive mechanism for 37 and 33. 37 Expander for hot K2CO3 solution for energy recovery. 39 Evaporator concentrator for Na2S solution.41 Condenser for cooling and elimination of SO2. 43. Absorption of H2S gas in alkaline solution. 45 Compression of CO2 containing gases for introduction in to absorption tower. 47 Drive unit for item 45 and 249, Precipitate separator and recycle of clean solution. 51 Drying and purification of Na2S and packaging. 53 Reaction of SO2 in Na2SO3 and packaging.

[0174] In brief gases are purified from chemical impurities and sulfur containing gases are removed before CO2 removal.

[0175] After SO2 removal H2 S is removed by NaOH reaction. The Na2S is separated and purified.

[0176] In the process scheme the energy input for the high-pressure compression performed on the gases entering the absorption tower is recovered from the expansion of out put gasses.

[0177] A portion of the clean gas is separated and sent directly to combustion and energy recovery system in the steam generating.

[0178] The CO2 rich solution is expanded before the solution goes to desorption tower for further removal of CO2.

[0179] The energy required for reheating of the reflux is provide by gaseous stream after particulate removal.

[0180] Best Modes for carrying out the casting of liquid steels and steel alloys are explained in the FIGS. 8.

[0181] Steel is poured from secondary steel making reactor which in this case is also a teeming ladle to a tundish 1. The tundish has a stopper rod to control the flow of liquid steel. Steel falls on a refractory filter. 3 and through the filter pores to the reaction chamber 5. A mixture of endothermic gases CH4+CO2 is introduced in this chamber. The metal, which has given up its super heat, heat of fusion and is slightly under cooled in endothermic reaction, falls in to the mold. 9. Endothermic gases 11 are also passed through the pores of the mold to the outer surface of the solidifying material for heat extraction from the material. Uniform solidification takes place through the entire structure of the formed strand 13. The product gases of the CH4+CO2 flow partially up ward join the chamber gases and then flow out ward through channel 15 More CO2 or CH4 is injected in this channel to perform cooling reaction and then the gases are made to pass over catalyst surface for additional reaction 17. The water of reaction is drained out 19. This decrease in gaseous volume over the original volume provides a high driving force to the gases and the volatile metals in side the reaction chamber. The exit gases are used for energy generation in the boilers. The part of the CO2+CH4 gases which flowed downward along the strand are reinforced with more endothermic gases 31 for more cooling in the extended mold region 33 and then made to exit near the beginning of protective tunnel 35 along with up ward flowing CO/CO2 gases and may be used in the boiler system of the plant.

[0182] The strand has sufficient strength to be pulled by internally cooled steel rolls. 41 which are inside a protective atmosphere tunnel. 43 The mold gives the solidifying steel the required configuration flats or shapes 45.

[0183]
FIG. 9.A, B show a preferred arrangement for casting and its continuation to hot rolling, hot rolling operations showing various controls.

[0184] After withdrawal rolls there are few direction changing rolls from vertical to horizontal rolling. The strand is then passed through universal type rolls whose number depends upon the dimensions of mold. These high deformation stations as shown R1, R2, R3 whose purpose is to create uniform structure and eliminate complicated controlling arrangements after ward. There are few openings in the atmosphere protection tunnel., with atmosphere control gates at the beginning and ending of tunnel FIG. 9. The bare strand has measurement and control instruments. After the second gate there is a continuous train of four high-stands in the tunnel and tunnel has protective atmosphere of required chemical potentials. The main rolling is done in this tunnel which is more appropriate to call as warm rolling as the temperature may be around 1050-950° C. After the continuous train and gate no 10 and before gate no 11 there is a second measurement and control region 6. After this is a region of surface treatment. This region approximately finishes at 500° C. and a protective gate no 12 . A list of generally used controls and control equipment is given on FIG. 9 The steel under rolling is further lowered in temperature under control atmosphere and it is rolled in to coils. The coils are tempered at low temperature 100-200° C. for 1-2 hours. The surface treatment is performed in line and variable time periods require at different temperature. These are achieved by moving the oils up and down on rolls whose height can be varied or time periods can be varied by varying the amount of in line accumulation of strip between the stands.

[0185] A preferred arrangement for hot rolling of shapes is given in FIG. 10.

[0186] A preferred arrangement for hot rolling of shapes and thick sheets and the surface finishing treatment of cut lengths is given in FIG. 10. Operation shown here is for one size only. For more sizes the operation explained over here is repeated after rolling appropriate sizes on the main line. 1 shows casting of liquid steel in shapes and 3 is a train of continuous type stands producing the required shape in finished form. No 2 is a temperature adjustment stand. 4 is shear for cutting to required length. This piece is pushed to chamber 5 where it stays for variable time and specific temperature. Then it under goes a rolling operation at stand 6. Similar repeat is given at roll 7 and then it is left on bed 9 for specified time. The strand may be further rolled to produce a different size 10 and then repeat the same operation. In case the shape is cold rolled it goes on the continued line 11.

[0187] Preferred arrangement for sheet/strip rolling operation, termination at hot rolling stage, or continuation to cold rolling stage and coiling, or further continued to tempering, coating and coiling. This arrangement is shown in FIGS. 11.A, B, C, D.

[0188] When steel is desired to be cold rolled in continuation after the hot rolling stage, the surface treatment is omitted. The steel strand is further cooled to ambient temperature before entering the first cold rolling stand. After rapid solidification at 1 the strand passes through universal type stands 3,. It passes through open portion of measuring instrument 5, then through continuous train of rolling 9 and continues to travel on the continuation line with cooling it down to ambient temperature 35 and entering continuos cold rolling stands 36. It may be coiled at 37 or go to accumulator 23 and then to continuous annealing 25 to second accumulator and cooler 26, 27 and passes through temper rolling 28 to coiler 32.

[0189] Mechanical arrangement with protective rolling. FIG. 12.A,B.

[0190] The best mode to carry out this invention that is the design of the rolls and seals to maintain pressure tight arrangements inside the tunnel is shown in the FIG. 12 .A ,B. An arrangement of four high stands with sliding seals and rotating seals and cooling of the steel rolls are shown. All rolls inside the tunnel are cooled. A sliding seal and rotating seal combination is illustrated. I A metal plate is attached to a rotating cylinder 3 but is not rotating with the cylinder and is firmly held against the surface of the metal shell of the tunnel. 2 is a covering arrangement provides an up and down movement to 1 along with cylinder but also keep the plate 1 attached to the surface. 4 are a circular cylinder attached to 1 and fixed in position. 5 rotates with rotating cylinder neck but is firmly pressed against 4 by a skirt type spring mechanism. 6 are internal support for roll surface.

[0191] Thus, by means of present inventions a steel plant may be constructed in which various type of steels and steel alloys can be manufacture by use of iron and alloy forming materials, reductant and flux. Using scrap and mixed sulfide ores micro alloy and high alloy steel can be produced The design of each unit process while carrying the desired aim of steel production to forward direction is also to eliminates the impurities and defects from steel and provides it a better finish. Same rolling facilities can be used for different steels with adjustment of control of parameters. With appropriate energy recovery from out going streams of the steel making process, recovery of heat generated during the rolling process, recovery of cold values from fractionated gases; and recovery of valuable trump element from charge decrease the over all energy and production cost considerably as compared to conventional values. There is no environments, water or gases pollution Eliminating the use of direct cooling water eliminates lots of equipment, and use of gas solid co-current process in the high temperature reactor eliminates agglomeration process and solves the problems of blown out fine charge. A new rolling process eliminates problems with scale formation, casting defects, reheating furnace, pickling and acid disposal. There are two or three main processes (comprising unit processes and unit operations) from production to shaping of steel. Each unit operation is to be given under microprocessor control, unit process under a plant computer and then the main process under central computer providing high operational efficiency and quality control. With simplicity of design low over all investment costs will be achievable

[0192] Briefly stating our over all aims of shorter production routes, high energy efficiency per ton of finished product, no pollution contribution, better controls and low investment cost are achieved.

[0193] Of course it will be realized that variations and modifications of the illustrated embodiment might be employed without departing from the inventive concepts herein.

Claims

1. A process for the treatment of a charge of steel scrap and coal for the separation of metals and non metals not required in steels and steel alloys compositions; comprises the steps of: introducing the charge into an inlet end of a primary reactor of a reactors system having an inlet end and an outlet end while injecting oxygen into said primary reactor near said inlet end and passing the charge through said primary reactor to said outlet end thereof: discharging said charge through a sealed connection into an inlet end of a next reactor for increasing the temperature and changing the chemical potential of said next reactor having an inlet and out let end and passing said charge through said next reactor. elements are separated in a unit process as melted groups and volatile groups and hereafter taken out of the reactor and separated into individual elements by fractional condensation of volatile and phase separation for liquids. unit processes are separated from each other and have independent means of input and outputs, control of chemical potentials and temperatures, have means to transfer gases and material from one unit -process to the next, volatile exiting from each unit process are made free of condensable materials and there after sent to particles recovery and removal of chemical impurities from gases. Several gaseous streams exiting from different unit processes are combined before going to particles and impurities removal. recovered blown out charge particles are recycled to the above said primary reactor. and recovered clean gases are recycled for various uses. discharging the said charge purified from impurity ingredients from an ending reactor of the above said reactors system having out let connected with a steel making reactor through above said sealed connection.
2. A process for obtaining mixed charge from sulfide ores as substitute of steel scrap for the manufacturing of steel alloys as in claim 1; comprising the steps of: introducing sulfide ores into an inlet end of a primary reactor of a reactors system and discharging said charge through a sealed connection into an inlet end of a next reactor for increasing the temperature and changing the chemical potential of said next reactor having an inlet and out let end and passing said charge through said next reactor. introducing in an inlet end of an internal reactor inside primary reactor a mixture of endothermic gases over a catalyst while sulfide ore is being given a roasting treatment with O2, in which the melted metals and volatile gases are led out of the reaction system and concentrated SO2 and volatile elements are recovered before sending the gases to particles recovery and separation of chemical impurities. The reformed gaseous mixer obtained from internal reactor is used within the plant for other purposes. resulting oxides of the metals so formed are processed in the above said processing scheme for scrap in claim 1.
3. A process for obtaining iron oxides and alloying element oxides from mixed refractory oxides and iron aluminum silicate ores comprising the steps of: introducing a mix of refractory metal oxides, iron aluminum silicate ore and coal in an inlet near the upper ending of a rotary reactor, this reactor has a lower outlet for heated charge and outlet for product gases near the reactor's upper ending. Heated solid charge therefrom is introduced to an ending reactor having means of receiving heated charge, means for inlet of clean gases and oxidizing gases, means for slag discharge and means for out let of high density products. It has means for the introduction of sodium carbonate near it upper ending. sodium salts formation is carried out in an oxidizing atmosphere in a temperature range of 1000-1300° C., low density liquid slag material is allowed to flow out as upper layer and heavy density solid material is withdrawn from the bottom of the reactor, from high density material FeO- Fe3 O4 is separated by magnetic means. top gases from the system are freed of blown out charge and then freed of chemical impurities. CO2 and clean gases CO,H2 obtained are reused within the system. sodium salts are changed to Na2 CO3 by blowing CO2. Sodium Carbonate is recovered and recycled. Iron oxides so obtained is mixed with other alloy forming oxides recovered within the system and further processed for production of alloy steels.
4. A process for the manufacturing of steel and steel-alloys comprising the steps of: introducing a charge material of iron and alloys making ingredients and coal in a steel making reactor having charge inlet means; processing the charge within this reactor and discharging the products through steel output means, slag discharge means, heavy metal discharge means and product gases output means. oxidizing and reducing gases and their combinations are introduced above and below above said slag layer. Meanwhile causing in put gases to flow co-current to the introduced charge, wherein the temperature inside the reactor is made higher than the decomposition temperature of iron oxides. Whereby non required ingredients in the charge are changed to volatile. Exit gases from steel making reactor are lowered in temperature by introduction of endothermic gases in the gaseous stream, steel-making reactors have refractory cooling arrangements by endothermic means. wherein excess carbon is introduced to solubilise the alloying elements in iron, thereafter excess carbon is removed in the same vessel, as a result of this some carbon may remain in the liquid steel or the liquid is having excess oxygen. Processing is facilitated by sampling of product streams and by making gaseous input under the slag layer. there after liquid steels go to composition adjustment process. Slag are discharge to a heat recovery process, product gases are sent to energy and particles recovery processes and removal from chemical impurities. A part of the clean gases is introduced in the steel making reactor. Recovered charge particles are introduced into the said charge introduction means of this reactor.
5. A process for heat recovery from slag as claimed in claim 4. in which an endothermic gases mixture is blown through slag film or micro-drops, and product gases therefrom go to a energy recovery system
6. A process for the composition adjustment of steels as in claim 4, comprising the steps of: eliminating excess carbon by blowing CO2 and O2 gases of specific composition, thereafter the oxidized alloying elements are recovering back to liquid steel with the addition of deoxidants, meanwhile blowing of CO. H2 mixture in the liquid steel. removing excess O2 from steels by blowing a mixer of CO2 and CH4, simultaneously adjusting composition of CO2 and CH4 to achieve a desired temperature of the bath.
7. A gas purification process for product gases obtained from steel making process as claimed in claim 4, where by off gases from steel making operation are made to flow directly out of steel making reactor. Temperature of these out going gases is made to decrease by injecting endothermic gases in the hot gases. off gases from steel making reactor may be led out, for recovery of volatile elements, energy and blown out charge particles, where after gases are made to flow to removal from chemical impurities. During the chemical impurities removal steps, sulfur containing gases are removed before the CO2 removal, desorption of CO2 from the solution is made by using heat energy contained in the impure gaseous stream. energy spent in the compression of gases and solutions is regained by expansion of gases and liquids, clean gases obtained are recycled for uses in the steel making and auxiliary operations.
8. A process for the shaping of steels comprises the steps of: recovering heat from liquid steels by performing endothermic reaction in direct contact with the liquid material, where in to create an intimate contact between liquid and gases, the liquid is given the shape of small droplets or thin liquid film. exit gases after performing endothermic reactions are led to combustion process for steam generation. Endothermic reaction is performed in a refractory lined steel chamber; with controlled entry and exit of reactant and product gases, and with control entry of liquid steel. In which during cooling process the solidifying steel is given an appropriate form; flat, shape or near net shape while castings in a mold of appropriate dimensions. The mold is a steel shell internally lined with porous refractory; which is endothermically cooled. steel is taken up by withdrawing rolls as it exits from the mold, and it is rolled in a tunnel having protective atmosphere of gases. during solidification and rolling processes the surface and interior temperature is kept same and entrapped gases continue to diffuse out as the temperature of the material is lowered, during solidification and rolling, material is compressed by internally cooled chromium steel lined rolls, additional heat balancing arrangements are provided for controlled cooling of solidifying steel strand.
9. A process for the shaping of steel under protective atmosphere as in claim 8,comprising the steps of: protective atmosphere in the tunnel is provided by CO/CO2 mixtures which are not oxidizing to steel at the rolling temperatures under practice, temperature inside the tunnel is made to decrease at a controlled rate, strand is made to exit through an atmosphere controlling exit gate. This gate has a slit of approximately of the same dimensions as the rolled shape or flat. Steel strand pass through the slit but the flow of gases is blocked, similar gates are at the ending and start of the tunnel where at gaps are created in the continuity of the tunnel. a protective atmosphere within the tunnel is maintained by means of sliding and rotating seals around the rolls. Into these seals a coolant for the internal cooling of the rolls can be introduced and made to exit through other-side seals.
10. A hot shaping process of steels as claimed in claim 8, comprising the steps of: There being an open space as a tunnel covering after a heavy rolling area is made to end and before the start of the tunnel housing the continuous train of rolls, continuous rolling operation is carried under appropriate reduction potential and temperature, both of these may be varied depending on the type of steel being rolled. There being an other similar open section after continuous rolling train, In open spaces measurement and control instruments are installed. after the above said second open section the surface finishing process starts, where in surface finishing started at upper critical temperature of the steel and is continued to lower critical temperature. surface finishing process is continuous in line for the strip. Where as shapes are cut to an appropriate length then pushed to a side chamber whose temperatures and chemical potentials are maintained as required. Steel is rolled as it exits from this chamber. it is given an other pass through a next chamber at a lower temperature and then under goes similar rolling as before. This process is repeated with controlled lowering of temperature until finishing dimensions are achieved. The end products of the shaped material are control tempered at 100-200° C. strip products; after in line surface treatment is taken out to a lower elevation for winding purpose, where coiled strip is tempered at 100-200° C. for 1-2 hours.
11. A process for finishing the steel in cold rolled conditions with subsequent annealing, temper rolling and coating as in claim 10, comprising the steps of: cooling the hot rolled steel to ambient temperature and subsequently carrying it to continuous train of cold rolling stands, where after it is taken to continuous annealing process, annealing is done under controlled temperatures and chemical potentials according to the requirements of steel compositions. Annealing gas is H2, in which CO and N2 can be made variable. after cold rolling, the coil enters the continuous annealing section, where it is heated to about 750° C., after it passes through controlled atmosphere regions; first through oxidizing gases and then through reducing gases, it is given a temper rolling after appropriate cooling. annealing treatment is parallel for flats and shapes with changes in mechanical configuration.
12. A rolling process without protective seals around the rolls as claimed in claim 10: in which the tunnel can end just before and after the rolls and strand passes through the slits of atmosphere protecting gates, tunnel has such gates at both the ending, and desired atmosphere is kept within the tunnels. reducing gases are blown below and above the strand and before and after the rolls, off gases from the rolls are sucked and taken for energy recovery.
13. An air fractionation process for the manufacturing low temperature O2 and N2 where oxygen is used in production processes. cold values from O2 and N2 are recovered by producing cold gases, after giving up its cold value nitrogen is used as fertilizer in the surrounding area; and along with N2 lines there are CO2, and SO2 lines carrying these gases to fields. nitrogen is used as fertilizer as a replacement of ammonia, in fields nitrogen pipeline is buried a short distance below the plowing level and soil over the buried nitrogen pipes is mixed with bacterial clay consisting of animal and human excretion and decomposed vegetation growth. Mixture of CO2 and N2 is used as substitute of urea.

Parent Case Info

[0001] This application is Continuation-in-part of Ser. No. 09/546,014, filed Apr. 10, 2000 now abandoned.

Continuation in Parts (1)

	Number	Date	Country
Parent	09546014	Apr 2000	US
Child	10075110	Feb 2002	US

Production and shaping of steel and steel alloys

Information

Publication Number

Date Filed

Date Published

Inventors

CPC

US Classifications

International Classifications

Abstract

Description

Claims

Parent Case Info

Continuation in Parts (1)