Patent Application
20220363555
The present invention relates to a method for producing artificial zeolite using fly ash as raw material, especially the method for producing relating to industrial mass production of high-purity artificial zeolite.
In hydrothermal synthesis of zeolite, the starting composition comprises at least four components (in molar ratios), namely alkali (oxides of (NaOH, KOH) and the like (a base)), alumina, silica, and water, and zeolites are categorized into natural zeolite which exist naturally, synthetic zeolite which are synthesized by reagents, and artificial zeolite which are from waste and the like (fly ash, glass waste, etc.). The below-mentioned table 1 is the categorization of zeolites.
use
pharmaceutical
automobile industry etc.
of various ingredients, catalyst etc.)
etc.
conditioner,
conditioner, pet deodorant, water treatment, feed use
indicates data missing or illegible when filed
High-purity synthetic zeolites are crystalized under conditions such as temperature condition and reaction time using four components (not containing impurities) from “raw materials such as sodium hydroxide, potassium hydroxide as alkali raw material, water glass, colloidal silica, sodium silicate and the like as silica raw material, sodium aluminate, aluminum hydroxide, aluminum nitrate and the like as alumina raw material, and water”, in which the raw material are reagents, as the starting composition. Therefore, in the assessment of synthetic zeolites using reagents, it may be said as high-purity synthetic zeolite when the relative intensity ratio of the “X-ray diffraction pattern intensity” (hereinafter referred to as lattice constant) is the same.
On the other hand, though there are many productions of artificial zeolites using coal ash (fly ash) as raw material, since other than oxides of the four components necessary for zeolite conversion, namely “silica raw material (SiO2)”, “alumina raw material (Al2O3)”, “alkali raw material (Na2O, K2O)”, impurities of iron, calcium, magnesium, sulfur, fluorine, boron, carbon compounds are contained in fly ash and most artificial zeolites produced without treating fly ash with some sort of method completely differ with the X-ray diffraction (lattice constant) relative intensity value of synthetic zeolite, it may be assessed as artificial zeolite of low-purity. The below-mentioned table 2 is the analysis value of the trial fly ash, ash of Datong, China.
Provision of reference: Electric Power Development Co., LTD.
O2
O
O
O
O
indicates data missing or illegible when filed
Patent literature 1 (Japanese Patent Application H07-165418) discloses that conventionally, for producing an artificial zeolite using coal ash (fly ash) as raw material, most methods for producing perform hydrothermal reaction with an alkaline aqueous solution without removing impurities contained in fly ash in advance.
Moreover, stating that it is not especially limited as long as the iron content, calcium, sodium, magnesium and other impurities contained in fly ash can be dissolved and washed using strong acid, patent literature 1 discloses dissolving with a strongly acidic aqueous solution such as sulfuric acid, hydrochloric acid (90 weight percent to 100 weight percent concentration, 10 to 50 volume percent concentration) as a specific example. With low concentration less than the above-mentioned predetermined range, impurities dissolve poorly and pickling cannot be sufficiently performed. Moreover, it is described that even if it exceeds the above-mentioned predetermined range, the washing effect is not improved so much, and it is not practical from the viewpoint of usage efficiency. Further, it is described that in this method for producing, if one or more zeolitic auxiliary agents selected from sodium aluminate, colloidal silica and sodium silicate is added to the mixture, the purification of zeolite is further promoted.
Moreover, it is described in Examples 1 to 6 of patent literature 1 that fly ash was used as raw material, and that 1 liter of an aqueous solution of 30 volume percent industrial concentrated sulfuric acid was warmed to 80° C., 500 g of fly ash was put in and left for 3 hours. Next, the dissolved component was washed and removed by water. Then, 50 g of fly ash after washing and the required amount of NaOH and colloidal silica was put in 100 ml of water and mixed and stirred, then sodium aluminate was dissolved in 200 ml of water, was added to said heated mixture while stirring, was reacted at reaction temperature, reaction time, stationary state, and thereafter, filtering off the solid content, zeolites of Examples 1 to 6 were obtained.
However, the conventionally known method for producing artificial zeolite is a synthesis method in laboratory scale preparing samples of small amounts over hours and cannot be said to be capable of mass production industrially.
The purpose of the invention is to provide a method for producing high-purity artificial zeolite suited for mass production in industrial scale, not laboratory scale.
In the present invention, impurities other than necessary during artificial zeolite conversion from fly ash is removed by firstly carrying out osmosis treatment of fly ash in an alkaline aqueous solution, subsequently carrying out the osmosis treatment again with a pH (1.0 or less) acidic aqueous solution obtained by adding acid (hydrochloric acid, sulfuric acid, nitric acid, and the like) to the alkaline aqueous solution (fly ash osmotic treatment solution), then performing solid-liquid separation while water wash and dewatering in a centrifuge. thereby synthesizing a starting composition, and performing hydrothermal reaction treatment to this starting composition. By this, out of the four components for artificial zeolite conversion, silica raw material (SiO2), a trace amount of alkali raw material (Na2O, K2O) containing products other than SiO2, a trace amount of Na2O, K2O in a trace amount having little effect during artificial zeolite conversion is obtained, and the starting composition comprising also the deficient components sodium aluminate, aluminum hydroxide, and water is performed with hydrothermal reaction treatment. By this method for producing, a method for producing relating to industrial mass production of a high-purity artificial zeolite which its X-ray diffraction (lattice constant) relative intensity value is approximately equivalent to synthetic zeolite was found, and have come to complete the present invention.
The present invention regards to a method for producing an artificial zeolite in which a high-purity artificial zeolite is industrially mass produced by carrying out osmosis treatment of fly ash in an alkaline aqueous solution, subsequently carrying out the osmosis treatment again with an acidic aqueous solution of pH 1.0 or less obtained by adding acid to the osmotic aqueous solution of fly ash, then performing solid-liquid separation while water wash and dewatering in a centrifuge, thereby synthesizing a starting composition, and performing hydrothermal reaction treatment to this starting composition.
The mass ratio of said fly ash and the alkaline aqueous solution is preferably 1:10 to 25. Moreover, regarding said alkaline aqueous solution, the molar ratio of NaOH/KOH is preferably 1.0 and the pH is preferably 13.0 or more. Osmosis treatment is carried out to said alkaline aqueous solution at normal temperature of 5 to 25 degrees for 1 to 48 hours. And then, an acid aqueous solution is added, and osmosis treatment is carried out at normal temperature of 5 to 25 degrees for 1 to 48 hours. Said acid is preferably sulfuric acid, hydrochloric acid, or nitric acid, and the like. Thereafter, solid-liquid separation is performed while water wash in a centrifuge. A white crystal product like silica is obtained by dewatering. By the above method, impurities other than products of SiO2 and a trace amount of alkali Na2O, K2O can be removed.
The flow chart of this method is shown in
The zeolite manufacturing equipment device (the present plant) of the present invention is shown in
Industrial mass production of high-purity artificial zeolite is capable by using a series of manufacturing equipment (notated as the present plant), such as a high-temperature and high-pressure device (autoclave) of maximum capacity 130 L (maximum temperature 180° C.·maximum pressure 1.5 MPa)·a once-through boiler (160kg/h·1.5 Mpa)·a centrifuge·an electric furnace.
Regarding a method for producing relating to industrial mass production of high-purity artificial zeolite, since zeolites are roughly classified into zeolites showing hydrophilicity with low SiO2/Al2O3 ratio (A-type SiO2/Al2O3=1.0 to 2.0 X-type SiO2/Al2O3=2.5 to 5.0) etc. and zeolites having hydrophobicity such as CHA, MOD, Y-type with high SiO2/Al2O3 ratio, the method of producing a representative hydrophilic A-type artificial zeolite and a hydrophobic Y-type artificial zeolite using a starting composition of SiO2, a trace amount of Na2O, KOH, which are obtained by the method for removing impurities other than necessary during artificial zeolite conversion, and others, namely sodium aluminate, aluminum hydroxide as alumina raw material, sodium hydroxide as alkali raw material, water, is described in the Examples using the zeolite device (the present plant).
The below-mentioned is the method for producing a representative hydrophilic A-type artificial zeolite.
As the production condition for making the A-type artificial zeolite a single crystalline phase, for the starting composition, the A-type starting composition is made to comprise in molar ratios 2.0 for SiO2/Al2O3, 1.0 for Na2O/SiO2, 56 for H2O/Na2O.
The ratio of the four components is made up of SiO2 obtained by removing impurities as silica raw material (ignoring the trace amount of alkali Na2O), sodium hydroxide as alkali raw material, aluminum hydroxide as alumina raw material, and water.
20.2 kg of fly ash from which impurities were removed (SiO2 is 11.85 kg since the SiO2 concentration of fly ash is 58.7%) was added to 100 liters of 2.0N alkaline aqueous solution (8.0 kg of NaOH and 92.0 liters of H2O), stirred for 0.3 to 1 hour, and a translucent solution was obtained. Then, 16.9 kg of aluminum hydroxide (Al2O3 is 10.05 kg since Al2O3 is contained of 59.5% in the above-mentioned aluminum hydroxide) was added to this solution, stirred until it became a white turbid solution, then the gel slurry solution kept at 60 to 40° C. was transferred to an autoclave, and with the setting of 100° C. temperature and 4 hours reaction time, hydrothermal reaction treatment was performed and the gel slurry of A-type artificial zeolite composition was obtained. After performing cooling precipitation for 1 to 24 hours to the gel slurry of the A-type composition, tap water was removed and while washing, solid liquid separation and dewatering at pH 10 or less was performed in a centrifuge, subsequently dried in an electric furnace at 100° C. for 7 hours, and crystallization of hydrophilic white A-type artificial zeolite was obtained. Regarding lattice constant (A) upon XRD analysis of the obtained crystal composition, high-purity A-type artificial zeolite was industrially mass produced (42.29 kg per batch).
Further, a comparison diagram of the X-ray analysis data diagram of the A-type artificial zeolite of Example 1 is shown in
The lattice constant intensity (CPS) of Example 1 of the present application of
The ratio of the lattice constant intensity of Comparative Example and Example 1 is 165000/240000=0.666.
Therefore, the lattice constant intensity of
Out of the above-mentioned molar ratios, SiO2/Al2O3 becomes 1.0 for the below-mentioned reason.
Since the mass of SiO2 is 11.85 kg, and the molecular weight of SiO2 is 60, 11.85/60 is 0.1975.
Since the mass of Al2O3 is 10.05 kg, and the molecular weight of Al2O3 is 102, 10.05/102 is 0.09852.
Therefore, the molar ratio SiO2/Al2O is 0.1975/0.09852, namely 2.0.
Out of the above-mentioned molar ratios, Na2O/SiO2 becomes 1.0 for the below-mentioned reason.
Since 99 percent of 8.0 kg of NaOH becomes Na2O, the mass of Na2O is 7.92 kg. Replaced with NaOH, since the molecular weight of NaOH is 40, 7.92/40 is 0.198.
Since the mass of SiO2 is 11.85 kg, and the molecular weight of SiO2 is 60, 11.85/60 is 0.1975.
Therefore, the molar ratio Na2O/SiO2 is 0.198/0.1975, namely 1.0.
Out of the above-mentioned molar ratios, H2O/Na2O becomes 56 for the below-mentioned reason.
Since the alkaline solution is an alkaline solution of 2.0N in Example 1, H2O/Na2O is 56 with regards to the concentration of 2.0N of NaOH from the below-mentioned table 3. Table 3 is a chart of molar ratios.
.7
From the molar ratio chart, the concentration of
N of NaOH is H2O/Na2O (58).
indicates data missing or illegible when filed
The below-mentioned is the method for producing a representative hydrophilic X-type artificial zeolite.
As the production condition for making the X-type artificial zeolite a single crystalline phase, for the starting composition, the X-type starting composition is made to comprise in molar ratios 5.0 for SiO2/Al2O3, 0.8 for Na2O/SiO2, 40 for H2O/Na2O.
The ratio of the four components is made up of SiO2 obtained by removing impurities as silica raw material (ignoring the trace amount of alkali Na2O), sodium hydroxide as alkali raw material, aluminum hydroxide as alumina raw material, and water.
30.6 kg of fly ash from which impurities were removed (SiO2 is 17.96 kg since the SiO2 concentration of fly ash is 58.7%) was added to 100 liters of 2.7N alkaline aqueous solution (10.0 kg of NaOH and 90.0 liters of H2O), stirred for 0.3 to 1 hour, and a translucent solution was obtained. Then, 10.2 kg of aluminum hydroxide (Al2O3 is 6.069 kg since Al2O3 is contained of 59.5% in the above-mentioned aluminum hydroxide) was added to solution (A), stirred until it became a white turbid solution, then the gel slurry solution (B) kept at 60 to 40° C. was transferred to an autoclave and with the setting of 100° C. temperature 5 hours reaction time, hydrothermal reaction treatment was performed and the gel slurry of X-type artificial zeolite product was sought. After performing cooling precipitation for 1 to 24 hours to the gel slurry of the X-type product, tap water was removed and while washing, solid liquid separation and dewatering at pH (10 or less) was performed in a centrifuge, subsequently dried in an electric furnace (100° C. 7 hours), and crystallization of hydrophilic white X-type artificial zeolite was obtained. Regarding lattice constant (A) upon powder XRD analysis of the obtained crystal product, high-purity X-type artificial zeolite (table 2) was industrially mass produced (46.51 kg per batch).
Further, a comparison diagram of the X-ray analysis data diagram of the
X-type artificial zeolite of Example 2 is shown in
The X-ray analysis data are shown in
The lattice constant intensity (CPS) of Example 2 of the present application of
The ratio of the lattice constant intensity of Comparative Example 2 and Example 2 becomes 230000/350000=0.657.
Therefore, the lattice constant intensity of Comparative Example 2 of
Further, the calculation of molar ratio of X-type artificial zeolite starting composition of Example 2 is the same with the method of calculation of A-type artificial zeolite of Example 1. The same applies to the following.
The below-mentioned is the method for producing a representative hydrophobic Y-type artificial zeolite.
As the production condition for making the Y-type artificial zeolite a single crystalline phase, for the starting composition, the Y-type starting composition is made to comprise in molar ratios 10 for SiO2/Al2O3, 0.5 for Na2O/SiO2, 44.5 for H2O/Na20. Similar to the description in Example 1, the ratio of the four components is made up of SiO2 obtained by removing impurities as silica raw material (ignoring the trace amount of alkali Na2O), aluminum hydroxide as alkali raw material, aluminum hydroxide as alumina raw material, and water. 50.5 kg of fly ash from which impurities were removed (SiO2 is 29.64 kg since the SiO2 concentration of fly ash is 58.7%) was added to 50 liters of 2.5N NaOH aqueous solution (5 kg of NaOH and 45 liters of H2O), stirred for 0.5 to 1 hour, and a translucent solution is obtained. Next, 8.4 kg of aluminum hydroxide (Al2O3 is 4.998 kg since Al2O3 is contained of 59.5% in the above-mentioned aluminum hydroxide) was added, stirred until it became a white turbid solution and a gel slurry solution was obtained, then a translucent solution was added to the gel slurry solution, transferred to an autoclave, and after being aged for 12 to 24 hours keeping 60 to 50° C., with the setting of 100° C. temperature and 24 hours reaction time, hydrothermal reaction treatment was performed and the gel slurry of Y-type artificial zeolite composition was sought. After performing cooling precipitation for 1 to 24 hours to the gel slurry of the Y-type composition, tap water was removed and while washing, solid liquid separation and dewatering at pH (10 or less) was performed in a centrifuge, subsequently dried in an electric furnace (100° C., 7 hours), and crystallization of hydrophilic white Y-type artificial zeolite was obtained. Regarding lattice constant (A) upon powder XRD analysis of the obtained crystal composition, high-purity Y-type artificial zeolite was industrially mass produced (67.1 kg per batch).
The below-mentioned is the method for producing a representative hydrophobic MOD-type artificial zeolite.
As the production condition for making the MOD-type artificial zeolite a single crystalline phase, for the starting composition, the MOD-type starting composition is made to comprise in molar ratios 15.6 for SiO2/Al2O3, 0.3 for Na2O/SiO2, 56 for H2O/Na2O. The ratio of the four components is made up of SiO2 obtained by removing impurities as silica raw material (ignoring the trace amount of alkali Na2O), sodium hydroxide as alkali raw material, aluminum hydroxide as alumina raw material, and water.
33.7 kg of fly ash from which impurities were removed (SiO2 is 19.78 kg since the SiO2 concentration of fly ash is 58.7%) was added to 50 liters of 2.0N alkaline aqueous solution (4.0 kg of NaOH and 46.0 liters of H2O), stirred for 0.3 to 1 hour, and a translucent solution was obtained. Then, 3.6 kg of aluminum hydroxide (Al2O3 is 2.142 kg since Al2O3 is contained of 59.5% in the above-mentioned aluminum hydroxide) was added to this solution, stirred until it became a white turbid solution and a gel slurry solution (B) was obtained, then a translucent solution (A) is added to the gel slurry solution (B), transferred to an autoclave, and after being aged for 12 to 24 hours keeping 60 to 50° C., with the setting of 175° C. temperature·16 hours reaction time, hydrothermal reaction treatment was performed and the gel slurry of MOD-type artificial zeolite product was sought. After performing cooling precipitation for 1 to 24 hours to the gel slurry of MOD-type product, tap water was removed and while washing, solid liquid separation and dewatering at pH (10 or less) was performed in a centrifuge, subsequently dried in an electric furnace (100° C., 7 hours), and crystallization of hydrophilic white MOD-type artificial zeolite was obtained. Regarding lattice constant (Å) upon powder XRD analysis of the obtained crystal product, high-purity MOD-type artificial zeolite was industrially mass produced (42.5 kg per batch).
The below-mentioned is the method for producing Na—P type artificial zeolite which can produce both a representative hydrophilic and hydrophobic.
As the production condition for making the hydrophilic Na—P type artificial zeolite a single crystalline phase, for the starting composition, the hydrophilic Na—P type starting composition is made to comprise in molar ratios 2 for SiO2/Al2O3, 1.0 for Na2O/SiO2, 33 for H2O/Na2O. Similar to the description in Example 1, the ratio of the four components is made up of SiO2 obtained by removing impurities as silica raw material (ignoring the trace amount of alkali N2O), aluminum hydroxide as alkali raw material, aluminum hydroxide as alumina raw material, and water.
30.7 kg of fly ash from which impurities were removed (SiO2 is 18.02 kg since the SiO2 concentration of fly ash is 58.7%) was added to 100 liters of 3N NaOH aqueous solution (12 kg of NaOH and 88 liters of H2O), stirred for 0.5 to 1 hour, and a translucent solution was obtained. Next, 25.4 kg of aluminum hydroxide (Al2O3 is 15.11 kg since Al2O3 is contained of 59.5% in the above-mentioned aluminum hydroxide) was added to the solution, stirred until it became a white turbid solution and a gel slurry solution was obtained, then transferred to an autoclave keeping the state of 60 to 40° C. temperature, and with the setting of 175° C. temperature and 1.5 hours reaction time, hydrothermal reaction treatment was performed and the gel slurry of Na—P type artificial zeolite composition was obtained. After performing cooling precipitation for 1 to 24 hours to the gel slurry of the Na—P type artificial zeolite composition, tap water was removed and while washing, solid liquid separation and dewatering at pH (10 or less) was performed in a centrifuge, subsequently dried in an electric furnace (100° C., 7 hours), and crystallization of hydrophilic white Na—P type artificial zeolite was obtained. The obtained crystal composition was a crystal of hydrophilic high-purity Na—P type artificial zeolite having high lattice constant (A) upon powder XRD analysis.
As the production condition for making the hydrophobic Na—P type artificial zeolite a single crystalline phase, for the starting composition, the hydrophobic Na—P type starting composition is made to comprise in molar ratios 10 for SiO2/Al2O3, 0.5 for Na2O/SiO2, 56 for H2O/Na2O. Similar to the description in Example 1, the ratio of the four components is made up of SiO2 obtained by removing impurities as silica raw material, sodium hydroxide of Na2O, which tends to be deficient, as alkali raw material, aluminum hydroxide as alumina raw material, and water.
40.4 kg of fly ash from which impurities were removed (SiO2 is 23.71 kg since the SiO2 concentration of fly ash is 58.7%) was added to 50 liters of 2N NaOH aqueous solution (NaOH (4.0 kg) and H2O (45 liters)), stirred for 0.5 to 1 hour, and a translucent solution was obtained. Next, 50 liters of 2N NaOH aqueous solution (4 kg of NaOH and 45 liters of H2O), 6.77 kg of aluminum hydroxide (Al2O3 is 4.02 kg since Al2O3 is contained of 59.5% in the above-mentioned aluminum hydroxide) was added, stirred until it became a white turbid solution and a gel slurry solution was obtained. A translucent solution was added to the gel slurry solution and transferred to an autoclave keeping the state of 60 to 40° C. temperature, and with the setting of 110° C. temperature and 6 hours reaction time, hydrothermal reaction treatment was performed and the gel slurry of Na—P type artificial zeolite composition was obtained. After performing cooling precipitation for 1 to 24 hours to the gel slurry of the Na—P type composition, tap water was removed and while cleaning, solid liquid separation and dewatering at pH (10 or less) was performed in a centrifuge, subsequently dried in an electric furnace (100° C., 7 hours), and crystallization of hydrophobic white Na—P type artificial zeolite was obtained. The obtained crystal composition was a crystal of hydrophobic high-purity Na—P type artificial zeolite having high lattice constant (A) upon powder XRD analysis.
From the above-mentioned, in the production for making the A-type artificial zeolite a single crystalline phase, the A-type starting composition is preferrable to comprise in molar ratios 1.0 to 2.0 for SiO2/Al2O3, 0.5 to 1.2 for Na2O/SiO2, 40 to 60 for H2O/Na2O.
In the production for making the X-type artificial zeolite a single crystalline phase, the X-type starting composition is preferrable to comprise in molar ratios 2.5 to 5.0 for SiO2/Al2O3, 0.5 to 1.2 for Na2O/SiO2, 40 to 60 for H2O/Na2O.
In the production for making the Y-type artificial zeolite a single crystalline phase, the X-type starting composition is preferrable to comprise in molar ratios 10 to 27 for SiO2/Al2O3, 0.5 for Na2O/SiO2, 40 to 60 for H2O/Na2O.
In the production for making the MOD-type artificial zeolite a single crystalline phase, it is preferrable to comprise 7.0 to 16 for SiO2/Al2O3, 2.6 for Na2O/SiO2, 56 for H2O/Na2O.
In the production for making the Na—P type artificial zeolite a single crystalline phase, the Na—P type starting composition is preferrable to comprise in molar ratios 1.0 to 12 for SiO2/Al2O3, 0.5 to 1.2 for Na2O/SiO2, 33 to 60 for H2O/Na20.
Further,
Zeolites have a pore structure called a channel in the crystal structure and can adsorb cations and water molecules in the internal cavity. By these features, zeolites are widely used industrially as catalysts, molecular sieves, adsorbents, and the like.
Information on crystal structure and ion is important in zeolite development, so information is obtained using powder X-ray (XRD Rietveld refinement) and the XRD pattern is simulated from lattice constant and atomic coordinates, and fitting of the actual measured powder XRD pattern is performed.
Herewith, evaluation decision of various zeolites is made by the coordinates, occupancy of the atom (ion).
As above, the present invention regards to a method for producing an artificial zeolite in which a high-purity artificial zeolite is industrially mass produced by carrying out osmosis treatment of fly ash in an alkaline aqueous solution, subsequently carrying out the osmosis treatment again with an acidic aqueous solution of pH 1.0 or less obtained by adding acid to the osmotic aqueous solution of fly ash, then performing solid-liquid separation while water wash and dewatering in a centrifuge, thereby synthesizing a starting composition, and performing hydrothermal reaction treatment to this starting composition. Therefore, it is a method for producing suited for mass production in industrial scale, not laboratory scale, and moreover, was able to provide an artificial zeolite of which the obtained crystal composition is high-purity.
This application is the United States national phase of International Application No. PCT/JP2019/028552 filed Jul. 19, 2019, the disclosure of which is hereby incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/028552 | 7/19/2019 | WO |
