Patent Application
20130009349
1. Field of the Invention
The present invention relates generally to a separation type metallurgical reduction method and an apparatus thereof. By means of the separation type metallurgical reduction apparatus, the metallurgical reduction/smelting process and the cooling process are separately performed in different spaces at the same time. In contrast, in a convent ional metallurgical reduction furnace, the smelting process and the cooling process must be performed in the same space and it is necessary to repeatedly raise and lower the temperature of the reduction furnace. Accordingly, by means of the separation type metallurgical reduction apparatus of the present invention, the operation time of the metallurgical process is greatly shortened to overcome the shortcoming of too long waiting time that exists in the conventional metallurgical reduction furnace. Moreover, by means of the separation type metallurgical reduction apparatus of the present invention, the energy consumption is greatly reduced and the yield rate is greatly increased.
2. Description of the Related Art
It is known that the developments of all kinds of industries have relied on sufficient supply and full application of specific materials for so long, especially some metal materials. Therefore, the metallurgical technique plays an important role in the advance of human society. The most important material used in the current electronic industries is silicon (Si). The sale of silicon-made components is about 95% of the sale of the semiconductor components in the world. In natural field, all silicon materials exist not in element state. Instead, the silicon materials exist in form of silica (impure SiO2) and silicate. Therefore, it is an important tropic in science and technology how to effectively and economically smelt silicon material from the natural raw material for manufacturing all kinds of silicon-made products.
In the above materials, metallurgical-grade Si (MG-Si) is a material of solar cell. The metallurgical-grade Si can be divided into three major varieties, that is, monocrystalline silicon, multicrystalline silicon and non-crystalline silicon. The raw material from which multicrystalline silicon or monocrystalline silicon is smelted is mainly high-purity (>97%) quartz sand, which is also a crystal of SiO2. The first step of manufacturing high-purity multicrystalline silicon is reducing silicon from silica. In a common manufacturing process, the materials of silica, coke, coal and woods are mixed and placed in a graphite electrical arc heating reduction furnace and heated at a high temperature of 1500° C.˜2000° C. to reduce SiO2 into silicon. The chemical reaction formulas are follows:
SiO2+C→Si+CO2
SiO2+2C→Si+2CO
In the conventional reduction technique, after the silica is placed into the reduction furnace, it is necessary to gradually raise the temperature of the reduction furnace from an ambient temperature to the high temperature of 1500° C.˜2000° C. for melting and reducing the material to be reduced. After the reduction process is completed, it is necessary to gradually lower the temperature of the reduction furnace to about 250° C. (approximate to the ambient temperature) for taking out the reduction product and avoiding abrupt temperature change, which may ill affect the equipment, the quality of the reduction product and the operation environment. After the reduction product is taken out from the reduction furnace, another crop of material to be reduced is placed into the reduction furnace. Then, it is necessary to gradually re-raise the temperature of the reduction furnace from the ambient temperature to the high temperature of 1500° C.˜2000° C. for melting and reducing the material. In the above process, it is necessary to repeatedly raise and lower the temperature of the reduction furnace. This is because in the case that the reduction furnace is opened under the high temperature of 1500° C.˜2000° C., there is a danger of explosion of the furnace body due to excessively great difference between the temperature of the furnace body and the temperature of the environment. Moreover, a great amount of high-temperature fluid will enter the operation environment to cause thermal contamination of the operation environment and injury to site workers. What is more, the abrupt temperature drop may lead to structural damage to the high-temperature smelted silicon product. Also, the silicon product will be inevitably contaminated with impurities in the environment and become useless.
According to practical estimation, one single cycle of the conventional metallurgical reduction of the silicon material (filling material→heating→reducing→lowering temperature→releasing product) will cost a quite long time of about 32 hours.
Moreover, after the temperature of the reduction furnace is continuously raised from about 250° C. to 1500° C.˜2000° C. for smelting the material and then gradually lowered to about 250° C. for taking out the reduction product, a great amount of thermal energy is lost and wasted. Furthermore, when re-raising the temperature of the reduction furnace from 250° C. to 1500° C.˜2000° C. for reduction, a great amount of electrical energy is consumed. Therefore, in the conventional metallurgical reduction method, a very long waiting time is wasted and the environment is contaminated. Also, a great amount of energy is wasted. This is not economic and fails to meet the requirement of environmental protection.
It is therefore tried by the applicant to provide a novel metallurgical reduction method and an apparatus thereof. By means of the separation type metallurgical reduction apparatus, the operation time of the metallurgical process is greatly shortened and the energy consumption is greatly reduced and the yield rate is greatly increased.
It is therefore a primary object of the present invention to provide a separation type metallurgical reduction method and an apparatus thereof. The separation type metallurgical reduction apparatus includes a reduction furnace and a multistage cooling device in cooperation with the reduction furnace. By means of the separation type metallurgical reduction apparatus, the reduction/smelting process of the material and the cooling process of the reduction product are separately performed in different spaces at the same time. Accordingly, the waiting time for re-rise of the temperature of the reduction furnace is greatly shortened so that the operation time of the metallurgical process is greatly shortened. Also, the energy consumption in each operation is greatly reduced in accordance with the requirement of environmental protect ion. Therefore, the production efficiency is greatly promoted and the yield rate is greatly increased.
To achieve the above and other objects, the separation type metallurgical reduction apparatus of the present invention includes a reduction furnace and a multistage cooling device. The reduction furnace serves to provide a high temperature for melting and reducing a material placed in the reduction furnace. The cooling device is connected with the reduction furnace in alignment with a material release passage thereof. The reduction product is released from the material release passage into the cooling device for cooling. Accordingly, the reduction/smelting process of the material and the cooling process of the reduction product are separately performed in different spaces at the same time. The cooling device includes a load chamber arranged under the reduction furnace. The material release passage is positioned between the load chamber and the reduction furnace. The internal space of the load chamber communicates with the internal space of the reduction furnace through the material release passage. A material release gate is disposed in the material release passage for controlling unblocking/blocking of the material release passage. In addition, a preheating chamber is arranged on one side of the load chamber in communication with the load chamber. A first load gate is disposed between the load chamber and the preheating chamber to control communication/non-communication between the preheating chamber and the load chamber. The preheating chamber is provided with a carrier input gate through which the carrier device can be input from outer side. A cooling chamber is installed on the other side of the load chamber in communication with the load chamber. A second load gate is disposed between the cooling chamber and the load chamber to control communication/non-communication between the cooling chamber and the load chamber. The cooling chamber is provided with a carrier output gate through which the carrier device can be moved out of the cooling chamber. In addition, a continuous conveying device is arranged in a path extending from outer side of the carrier input gate through the carrier input gate, the preheating chamber, the first load gate, the load chamber, the second load gate, the cooling chamber and the carrier output gate to the outer side of the cooling chamber. The conveying device serves to convey the carrier device through the path to carry the reduction product for the preheating and cooling processes stage by stage.
A material dropping device is disposed above the reduction furnace. A material dropping passage is positioned between the material dropping device and the reduction furnace, whereby the internal space of the material dropping device communicates with the internal space of the reduction furnace through the material dropping passage. A material dropping gate is arranged in the material dropping passage for controlling unblocking/blocking of the material dropping passage. The material to be reduced is filled in the internal space of the material dropping device. When the material dropping gate of the material dropping passage is opened to unblock the material dropping passage, the material to be reduced is allowed to drop into the reduction furnace through the material dropping passage.
According to the above arrangement, the reduction/smelting process of the material and the cooling process of the reduction product are separately performed in different spaces at the same time. Accordingly, the metallurgical reduction process and cooling process can be overlapped and performed at the same time crop by crop to shorten time interval between reduction processes of two crops of material to be reduced. Therefore, the production efficiency is promoted and the yield rate is increased. Moreover, the cooling device is separated from the reduction furnace and the carrier device is separately conveyed through the cooling device section by section so that the quality of the reduction product can be ensured. Also, the energy consumption is greatly reduced in accordance with the requirement of environmental protection.
The present invention can be best understood through the following description and accompanying drawings, wherein:
Please refer to
The reduction furnace 10 has an internal space in which the material to be reduced is placed (as shown in
A material dropping device 17 is disposed above the reduction furnace 10. A material dropping passage 171 is positioned between the material dropping device 17 and the reduction furnace 10, whereby the internal space of the material dropping device 17 communicates with the internal space of the reduction furnace 10 through the material dropping passage 171. A material dropping gate 172 is arranged in the material dropping passage 171 for controlling unblocking/blocking of the material dropping passage 171. The material to be reduced is filled in the internal space of the material dropping device 17. When the material dropping gate 172 of the material dropping passage 171 is opened to unblock the material dropping passage 171, the material 30 to be reduced is allowed to drop into the reduction furnace 10 (or the reduction pot 11). A material filling port 173 is disposed on an upper side of the material dropping device 17. An upper cover 174 is disposed at the material filling port 173 for blocking/unblocking the material filling port 173 so as to prevent the material 30 from being contaminated by ambient impurities. The material 30 to be reduced can be automatically regularly and quantitatively filled into the material dropping device 17 by means of a conveying belt to save labor and avoid inconvenience.
The cooling device 20 is arranged under a material release passage 16 of the reduction furnace 10. The cooling device 20 is provided with a load chamber 21. The internal space of the reduction furnace and the internal space of the load chamber 21 communicate with each other through the material release passage 16. A material release gate 161 is disposed in the material release passage 16 for controlling unblocking/blocking of the material release passage 16. The material can be previously input to at least one carrier device 40 in the internal space of the load chamber 21. The carrier device 40 is aligned with an exit of the material release passage 16 to accept the material output from the material release passage 16.
A preheating chamber 22 is installed on one side of the load chamber 21. A first load gate 221 is disposed between the load chamber 21 and the preheating chamber 22 to control communication/non-communication between the preheating chamber 22 and the load chamber 21. When the first load gate 221 is opened, the carrier device 40 can pass through the first load gate 221 into the load chamber 21. The preheating chamber 22 is further provided with a carrier input gate 222 through which the carrier device 40 can be input from outer side. In addition, a heating device 223 is further disposed in the preheating chamber 22 for heating the internal space thereof. The preheating chamber 22 mainly serves to preheat the input carrier device 40 and then input the carrier device to the load chamber 21 before the reduction product is input to the load chamber 21. This can avoid too large difference between the temperature of the carrier device 40 and the temperature of the reduction product so as to avoid ill affection on the reduction product or accident in the loading process.
A cooling chamber 23 is installed on the other side of the load chamber 21. A second load gate 231 is disposed between the cooling chamber 23 and the load chamber 21 to control communication/non-communication between the cooling chamber 23 and the load chamber 21. When the second load gate 231 is opened, the carrier device 40 can pass through the second load gate 231. A cooling fan 232 or the like circulation cooling device can be disposed in the cooling chamber 23 to speed the cooling operation. In addition, the cooling chamber 23 is provided with a carrier output gate 233 through which the cooled reduction product and the carrier device 40 are conveyed to outer side of the cooling chamber 23.
A continuous or multisection conveying device 24 is disposed in the preheating chamber 22, the load chamber 21 and the cooling chamber 23 between the gates thereof for conveying the carrier device 40. By means of the conveying device 24, the carrier device 40 can be input from outer side through the carrier input gate 222 to the preheating chamber 22. The carrier device 40 then is conveyed through the first load gate 221 into the load chamber 21 and then conveyed through the second load gate 231 into the cooling chamber 23. Finally, the carrier device 40 is conveyed through the carrier output gate 233 to the outer side. Accordingly, the carrier device (or the reduction product) can be conveniently and continuously conveyed. In addition, two carrier transportation trolleys 50 are respectively disposed behind the carrier input gate 222 of the preheating chamber 22 and in front of the carrier output gate 233 of the cooling chamber 23 for inputting the carrier device 40 to the conveying device 25 and outputting the carrier device 40 from the conveying device 25. Accordingly, the preheating chamber 22, the load chamber 21, the cooling chamber 23 and the conveying device cooperate with each other to form a separation type multistage cooling device, which can continuously convey the carrier device 40.
In addition, heat insulation devices 25 (preferably liquid-cooled or water-cooled heat insulation devices) are respectively disposed between inner walls and outer walls of the separated spaces of the cooling device 20 to prevent the high heat in the spaces from being conducted to outer side and protect the ambient environment from being thermally contaminated. Moreover, the internal spaces of the reduction furnace 10 and the cooling device 20 are all clean rooms (or vacuum rooms) to avoid contamination of the material or the product and ensure stable quality of operation.
Please now refer to
step 201 of filling the material 30 to be reduced into the material dropping device 17 and preparing the material 30;
step 202 of opening the material dropping gate 172 to quantitatively drop the material 30 to be reduced through the material dropping passage 171 into the internal space of the reduction furnace 10 (or the reduction pot 11);
step 203 of closing the material dropping gate 172 and the material release gate 161 to form a closed space in the reduction furnace 10;
step 204 of using the heating device 13 of the reduction furnace 10 to heat the material 30 to a high temperature so as to melt and reduce the material 30, in this step, the material 30 in the reduction furnace 10 being heated to a high temperature of 1500° C.˜2000° C. and molten, when heated and molten, a blending device 14 being used to uniformly blend the material 30 for reducing the material 30 into a reduction product 301;
step 205 of using the conveying device 24 to convey the preheated carrier device 40 from the preheating chamber 22 into the load chamber 21 in a position under the material release passage 16, then the first and second load gates 221, 231 being closed and then the material release gate 161 being opened to drop the reduction product 301 through the material release passage 16 into the carrier device in the load chamber 21;
step 206 of closing the material release gate 161 and further dropping another crop of material 30 to be reduced from the material dropping device 17 into the reduction furnace 10 for heating and reduction process, in the meantime, the second load gate 231 of the cooling device 20 being opened to convey the carrier device 40 with the reduction product 301 from the load chamber 21 into the cooling chamber 23 for cooling;
step 207 of closing the carrier output gate 233 and simultaneously (later) opening the carrier input gate 222 to convey the carrier device 40 from the outer side (the trolley 50) into the preheating chamber 22 for preheating:
step 208 of previously conveying the carrier device 40 into the load chamber 21 before step 205 is performed again; and
step 209 of cooling the reduction product 301 in the cooling chamber 23 to a set temperature relatively approximate to ambient temperature and then opening the carrier output gate 233 to convey the cooled reduction product 301 and the carrier device 40 out of the cooling chamber 23. The set temperature can be under 150° C.˜100° C. according to the current normal operation. In steps 206 to 208, a cooling fan 232 or the like cooling device can be used to speed the cooling process of the reduction product 301 and the carrier device 40 carrying the reduction product 301. The operation is performed in a clean or vacuum room. In addition, an inert gas can be released during the cooling process to keep the reduction product 301 in a stable state to complete the reduction process of one crop of material.
According to the aforesaid, the heating/reduction operation of the material 30 in the reduction furnace 10 and the cooling operation of the reduction product 301 are performed in different spaces at the same time. The blocking/unblocking of the material release passage 16 and the opening/closing of the respective gates are effectively controlled to keep the reduction furnace 10 at a high temperature. It is unnecessary to repeatedly raise/lower the temperature of the reduction furnace as in the conventional reduction furnace. Therefore, the energy consumption can be greatly reduced. Moreover, the time for each re-rise of the temperature of the internal space of the reduction furnace to a high temperature necessary for the reduction operation is greatly shortened. Therefore, the product ion efficiency is greatly promoted. Furthermore, the reduction stage of operation and cooling stage of operation are performed in separated environments and thus can be independently more flexibly and conveniently controlled as necessary to ensure high quality of the reduction product 301.
According to the above arrangement, the present invention has the following advantages:
The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.
