CN102910678B - Method for preparing sodium chromate - Google Patents
Method for preparing sodium chromate Download PDFInfo
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- CN102910678B CN102910678B CN201210482808.9A CN201210482808A CN102910678B CN 102910678 B CN102910678 B CN 102910678B CN 201210482808 A CN201210482808 A CN 201210482808A CN 102910678 B CN102910678 B CN 102910678B
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- sodium chromate
- sodium
- gas
- carbon dioxide
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- PXLIDIMHPNPGMH-UHFFFAOYSA-N sodium chromate Chemical compound [Na+].[Na+].[O-][Cr]([O-])(=O)=O PXLIDIMHPNPGMH-UHFFFAOYSA-N 0.000 title claims abstract description 79
- 238000000034 method Methods 0.000 title claims abstract description 62
- 239000000243 solution Substances 0.000 claims abstract description 86
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 49
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 23
- 239000011651 chromium Substances 0.000 claims abstract description 23
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 22
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 19
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 19
- 238000002386 leaching Methods 0.000 claims abstract description 17
- 239000012535 impurity Substances 0.000 claims abstract description 12
- 239000007787 solid Substances 0.000 claims abstract description 8
- 239000003637 basic solution Substances 0.000 claims description 38
- 239000011734 sodium Substances 0.000 claims description 29
- JHWIEAWILPSRMU-UHFFFAOYSA-N 2-methyl-3-pyrimidin-4-ylpropanoic acid Chemical compound OC(=O)C(C)CC1=CC=NC=N1 JHWIEAWILPSRMU-UHFFFAOYSA-N 0.000 claims description 23
- 239000002253 acid Substances 0.000 claims description 21
- 150000001718 carbodiimides Chemical class 0.000 claims description 19
- 238000002425 crystallisation Methods 0.000 claims description 13
- 230000008025 crystallization Effects 0.000 claims description 12
- 235000011089 carbon dioxide Nutrition 0.000 claims description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 239000012452 mother liquor Substances 0.000 claims description 9
- 239000008151 electrolyte solution Substances 0.000 claims description 8
- 238000001704 evaporation Methods 0.000 claims description 8
- 230000008020 evaporation Effects 0.000 claims description 8
- 230000018044 dehydration Effects 0.000 claims description 7
- 238000006297 dehydration reaction Methods 0.000 claims description 7
- 238000006386 neutralization reaction Methods 0.000 claims description 7
- 239000002351 wastewater Substances 0.000 claims description 6
- 239000012141 concentrate Substances 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 5
- 238000004519 manufacturing process Methods 0.000 abstract description 10
- 238000000926 separation method Methods 0.000 abstract description 4
- 230000003472 neutralizing effect Effects 0.000 abstract description 3
- 239000012670 alkaline solution Substances 0.000 abstract 2
- 230000002378 acidificating effect Effects 0.000 abstract 1
- 239000003795 chemical substances by application Substances 0.000 abstract 1
- 239000007789 gas Substances 0.000 description 31
- 239000000047 product Substances 0.000 description 15
- 239000000460 chlorine Substances 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 238000001914 filtration Methods 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 238000003756 stirring Methods 0.000 description 4
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 3
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 3
- 238000005119 centrifugation Methods 0.000 description 3
- 229910052801 chlorine Inorganic materials 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 229910052708 sodium Inorganic materials 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- 235000011941 Tilia x europaea Nutrition 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- QDOXWKRWXJOMAK-UHFFFAOYSA-N dichromium trioxide Chemical compound O=[Cr]O[Cr]=O QDOXWKRWXJOMAK-UHFFFAOYSA-N 0.000 description 2
- 239000004571 lime Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000001590 oxidative effect Effects 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 235000019738 Limestone Nutrition 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000010459 dolomite Substances 0.000 description 1
- 229910000514 dolomite Inorganic materials 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 238000004043 dyeing Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005868 electrolysis reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 239000005431 greenhouse gas Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000007639 printing Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 235000013599 spices Nutrition 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 229910021653 sulphate ion Inorganic materials 0.000 description 1
- 229920003051 synthetic elastomer Polymers 0.000 description 1
- 239000005061 synthetic rubber Substances 0.000 description 1
Landscapes
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention relates to a method for preparing sodium chromate. The method comprises the following steps: firstly, neutralizing sodium chromate alkaline solution obtained through chromite baking and leaching by using carbon dioxide gas or gas containing carbon dioxide; secondly, separating and removing solid impurities; and thirdly, adding acidic chromium-containing solution to the solution obtained through the separation in the second step to adjust the pH. Through the method disclosed by the invention, the product quality of sodium chromate is improved, and the production cost is further greatly reduced. The tail gas of industrial stoves is used as the neutralizing impurity removing agent of the sodium chromate alkaline solution so that the carbon dioxide gas is recycled and the production cost of sodium chromate can be further reduced.
Description
Technical field
The present invention relates to a kind of method of preparing Sodium chromate.
Background technology
Sodium chromate is as the basic material of Chrome Salt Industry, be the basic raw material of producing sodium dichromate 99, potassium bichromate, chromic trioxide, chrome green etc., be widely used in that plating, process hides, printing and dyeing, medicine, grease are refining, the industrial circle such as synthetic rubber, spices and stainless steel manufacture.Along with the industrialized development in the whole world, the demand of Sodium chromate also increases gradually.
The Sodium chromate of high-quality is yellow translucent monoclinic crystal (Na
2crO
44H
2o), by chromium acid sodium solution crystallisation by cooling and dehydration and make at the temperature of 25.9-68 DEG C.
First traditional preparation method of Sodium chromate uses sodium dichromate mother liquor or utilizes the solution of sodium dichromate finished product preparation by the neutralization of Sodium chromate basic solution, and then evaporative crystallization obtains product.Owing to using sodium dichromate mother liquor or utilizing the solution of sodium dichromate finished product preparation to regulate pH, this class methods products obtained therefrom quality is high.But, use sodium dichromate mother liquor or sodium dichromate finished product can cause production cost high, and Production Flow Chart complexity, inefficiency.
Chinese invention patent application CN 1181353A and CN 1226512A are directly by Sodium chromate basic solution evaporative crystallization.Although this class methods production efficiency is high, Production Flow Chart is simple, and owing to there is no removal of impurities process, products obtained therefrom quality is very low, lacks the market competitiveness.
In Industrial Stoves tail gas, contain a certain amount of carbon dioxide, it is directly discharged and can aggravate Greenhouse effect, cause environment further to worsen.
Summary of the invention
In view of above-mentioned prior art situation, present inventor has carried out research extensively and profoundly in Sodium chromate technical field, prepares the method for high-quality Sodium chromate to obtaining a kind of low cost.Found that can be by utilizing carbon dioxide or wrapping carbonated gas and the Sodium chromate basic solution neutralization obtaining by roasting chromite and leaching is realized above-mentioned purpose by acid chromium-containing solution successively.Contriver has completed the present invention based on above-mentioned discovery just.
Therefore, the object of this invention is to provide a kind of method that low cost is prepared high-quality Sodium chromate.
Another object of the present invention is to provide a kind of low cost and environmental friendliness prepares the method for high-quality Sodium chromate.
The technical scheme that realizes the object of the invention can be summarized as follows:
1. prepare a method for Sodium chromate, described method comprises:
I utilizes carbon dioxide or wraps carbonated gas by the Sodium chromate basic solution neutralization obtaining by roasting chromite and leaching;
II separates and removes solid impurity; With
III adds acid chromium-containing solution to regulate pH in the separating obtained solution of Step II.
2. according to the method for the 1st, wherein utilize carbonic acid gas that Sodium chromate basic solution is neutralized to pH for 8.5-9.5.
3. according to the 1st or the method for 2, wherein utilizing acid chromium-containing solution is 7.0-8.5 by pH regulator.
4. according to the method for any one in 1-3, wherein wrapping carbonated gas is the tail gas from Industrial Stoves.
5. according to the method for the 4th, wherein in the tail gas from Industrial Stoves, the content of carbonic acid gas is 1-99 volume %.
6. according to the method for any one in 1-5, wherein acid chromium-containing solution is that carborization is prepared the pre-carbodiimide solution, carbodiimide solution, electrolytic solution, dehydration mother liquor, waste water, wash water or its any mixing solutions that in sodium dichromate process, produce.
7. according to the method for any one in 1-6, wherein, before carrying out step I, the temperature of Sodium chromate basic solution is controlled between 90-105 DEG C.
8. according to the method for any one in 1-7, described method also comprises:
IV concentrates Step II I gained solution by evaporation, so that its concentration is controlled at Na
2crO
44H
2o counts 900-1100gL
-1.
9. according to the method for the 8th, described method also comprises:
Step IV gained solution is cooled to 26-68 DEG C by V, so that Sodium chromate crystallization.
10. prepare a method for Sodium chromate, described method comprises:
I utilizes carbon dioxide or wraps carbonated gas the Sodium chromate basic solution obtaining by roasting chromite and leaching is neutralized to pH for 8.5-9.5;
II separates and removes solid impurity;
III is 7.0-8.5 to adding acid chromium-containing solution in the separating obtained solution of Step II by its pH regulator;
IV concentrates Step II I gained solution by evaporation, so that its concentration is controlled at Na
2crO
44H
2o counts 900-1100gL
-1; With
Step IV gained solution is cooled to 26-68 DEG C by V, so that Sodium chromate crystallization;
Wherein, before carrying out step I, the temperature of Sodium chromate basic solution is controlled between 90-105 DEG C; Wrapping carbonated gas is the tail gas from Industrial Stoves, and its carbon dioxide content is 1-99 volume %; Acid chromium-containing solution is that carborization is prepared the pre-carbodiimide solution, carbodiimide solution, electrolytic solution, dehydration mother liquor, waste water, wash water or its any mixing solutions that in sodium dichromate process, produce.
The inventive method utilize successively carbon dioxide or wrap carbonated gas and acid chromium-containing solution if carbodiimide solution is by the Sodium chromate basic solution neutralization obtaining by roasting chromite and leaching, this has not only improved the quality product of Sodium chromate, and has significantly reduced production cost.The inventive method adopts Industrial Stoves tail gas as in Sodium chromate basic solution and cleaner, has both reclaimed carbon dioxide wherein, can further reduce again the production cost of Sodium chromate.
These and other purposes, features and advantages of the present invention are considered, after the present invention, will be easy to be understood by those of ordinary skill in entirety.
Embodiment
The method that the present invention prepares Sodium chromate comprises the steps:
I utilizes carbon dioxide or wraps carbonated gas by the Sodium chromate basic solution neutralization obtaining by roasting chromite and leaching;
II separates and removes solid impurity; With
III adds acid chromium-containing solution to regulate pH in the separating obtained solution of Step II.
First the inventive method step I utilizes carbon dioxide or wraps carbonated gas and neutralize the Sodium chromate basic solution obtaining by roasting chromite and leaching.This Sodium chromate basic solution contains Al
3+, Fe
3+, Cr
3+, SiO
3 2-deng impurity, carbonic acid gas is passed into and wherein makes solution be neutrality or weakly alkaline, and incite somebody to action thus wherein unwanted contamination precipitation and separate out.
Obtain Sodium chromate basic solution by roasting chromite and leaching known to those skilled in the art.For example, in the situation that having calcium roasting, by chromite powder, soda ash, limestone powder, ground dolomite and dry levigate return slag and mix, add in rotary kiln, high-temperature roasting, by clinker cooling, leaching makes Sodium chromate basic solution.The concentration of Sodium chromate basic solution is generally 200-600gL
-1(with Na
2crO
44H
2o meter), basicity is 10-100gL
-1(with Na
2cO
3meter).
Can directly utilize carbon dioxide to neutralize the Sodium chromate basic solution obtaining by roasting chromite and leaching.Advantageously, use the carbonated gas of bag by the Sodium chromate basic solution neutralization obtaining by roasting chromite and leaching.The example that wraps carbonated gas is the tail gas from Industrial Stoves.Different according to its source, in Industrial Stoves tail gas, the content of carbonic acid gas can be 1-99 volume %, and for example in lime burner furnace tail gas, the content of carbonic acid gas is that the content of carbonic acid gas in 30-40 volume %, cement kiln tail gas is that the content of carbonic acid gas in 15-20 volume %, chromite oxidizing roasting rotary kiln tail gas is 10-15 volume %.Owing to using the tail gas from Industrial Stoves that Sodium chromate basic solution is neutralized, Industrial Stoves tail gas has obtained recycling effectively, and has therefore reduced greenhouse gas emissions.Carbon dioxide or the consumption that wraps carbonated gas are as the criterion so that the Sodium chromate basic solution obtaining by roasting chromite and leaching is neutralized to required pH numerical range.
In step I, utilize carbon dioxide or wrap carbonated gas Sodium chromate basic solution is neutralized to pH for 8.5-9.5.
Step I can be at any suitable vessel, for example, be equipped with in the neutralizing well of whipping appts and carry out.
Generally speaking, stir and normal pressure under by carbon dioxide or wrap carbonated gas and pass in Sodium chromate basic solution, until reach required pH numerical range.
Advantageously, before carrying out step I, the temperature of Sodium chromate basic solution is controlled between 90-105 DEG C.
In the inventive method Step II, will in and Sodium chromate basic solution gained mixture separation, to remove solid impurity wherein.It is known to those skilled in the art that the method for solid impurity is removed in separation, for example, carry out as press filtration by filtering.
In the inventive method Step II I, utilize the pH value of the separating obtained solution of acid chromium-containing solution regulating step II.
Acid chromium-containing solution is that carborization is prepared the pre-carbodiimide solution, carbodiimide solution, electrolytic solution, dehydration mother liquor, waste water, wash water or its any mixing solutions that in sodium dichromate process, produce.Prepare in sodium dichromate process and obtain pre-carbodiimide solution by during carbonic acid gas is passed into chromium acid sodium solution at carborization, its concentration is 300-500gL
-1(with Na
2cr
2o
72H
2o meter), pH is 6.5-7.0.Prepare in sodium dichromate process and obtain carbodiimide solution in carbonic acid gas is passed into chromium acid sodium solution at carborization, its concentration is 900-1000gL
-1(with Na
2cr
2o
72H
2o meter), pH is 5.5-6.2.Prepare the mode by electrolysis in sodium dichromate process at carborization supplementary carbodiimide solution acidifying is obtained to electrolytic solution, its concentration is 900-1000gL
-1(with Na
2cr
2o
72H
2o meter), pH is 0.5-1.5.Prepare in sodium dichromate process after crystallization by sodium dichromate crystal separation is obtained to dehydration mother liquor at carborization, its concentration is 1000-1400gL
-1(with Na
2cr
2o
72H
2o meter), pH is 0.5-1.5.Waste water is the feed liquid that carborization is prepared quality dissatisfaction in sodium dichromate process, and its concentration is 300-400gL
-1(with Na
2cr
2o
72H
2o meter), pH is 0.5-7.0.Prepare in sodium dichromate process and obtain wash water by the sodium bicarbonate that washes by-product with water at carborization, its concentration is 100-400gL
-1(with Na
2cr
2o
72H
2o meter), pH is 5.5-7.0.
Due to acid chromium-containing solution, for example utilize carborization to produce the carbodiimide solution producing in sodium dichromate process, sulphate content is very low, not only control well the content of the impurity such as calcium, magnesium, iron, aluminium in Sodium chromate product, and solved well unmanageable vitriol problem in Sodium chromate production process.
The consumption of acid chromium-containing solution is as the criterion so that the pH value of the separating obtained solution of Step II is adjusted to required numerical range.
In Step II I, utilize acid chromium-containing solution that the pH value of the separating obtained solution of Step II is adjusted to 7.0-8.5.
The inventive method can also comprise: IV concentrates Step II I gained solution by evaporation, so that its concentration is controlled at Na
2crO
44H
2o counts 900-1100gL
-1thereby, be conducive to Sodium chromate crystallization.
Correspondingly, the inventive method can also comprise: step IV gained solution is cooled to 26-68 DEG C by V, so that Sodium chromate crystallization.Generally speaking, by water is carried out to described cooling operation as heat-eliminating medium.
As is known to the person skilled in the art, then separate and obtain Sodium chromate product by conventional meanses such as centrifugal, suction filtration or press filtrations.
Embodiment
Below by reference to embodiment, the present invention is specifically described, but described embodiment does not form any restriction to the scope of the invention.
Embodiment 1
By 1m
3the Sodium chromate basic solution obtaining by roasting chromite and leaching is heated to 100 DEG C and keep constant, and wherein the concentration of Sodium chromate basic solution is 537gL
-1(with Na
2crO
44H
2o meter).
Under stirring by 1000m
3wherein gas concentration lwevel is that the cement kiln tail gas of approximately 15 volume % passes in Sodium chromate basic solution, until the pH of described solution is reduced to 9.3, then uses plate-and-frame filter press press filtration, obtains the solution of transparent clear.
In the solution that is 9.3 to above-mentioned pH, add 0.3m
3producing the pre-carbodiimide solution in sodium dichromate process from carborization, is 8.3 by the pH regulator of described solution, and wherein the concentration of pre-carbodiimide solution is 357gL
-1(with Na
2cr
2o
72H
2o meter), pH is 6.6.
The solution evaporation that is 8.3 by above-mentioned pH to its concentration is 1099gL
-1(with Na
2crO
44H
2o meter), water cooling crystallization, when crystal solution temperature is reduced to after 35 DEG C, centrifugation obtains 187.9kg Sodium chromate product.
In gained Sodium chromate product, the content of Sodium chromate is that 98.3 % by weight are (with Na
2crO
44H
2o meter), vitriol is that 0.18 % by weight is (with SO
4 2-meter), chlorine root is that 0.03 % by weight is (with Cl
-meter).
Embodiment 2
By 1.1m
3the Sodium chromate basic solution obtaining by roasting chromite and leaching is heated to 90 DEG C and keep constant, and wherein the concentration of Sodium chromate basic solution is 452gL
-1(with Na
2crO
44H
2o meter).
Under stirring by 550m
3wherein gas concentration lwevel is that the lime burner furnace tail gas of approximately 31 volume % passes in Sodium chromate basic solution, until the pH of described solution is reduced to 9.0, then uses plate-and-frame filter press press filtration, obtains the solution of transparent clear.
In the solution that is 9.0 to above-mentioned pH, add 0.15m
3producing the carbodiimide solution in sodium dichromate process from carborization, is 7.8 by the pH regulator of described solution, and wherein the concentration of carbodiimide solution is 925gL
-1(with Na
2cr
2o
72H
2o meter), pH is 5.8.
The solution evaporation that is 7.8 by above-mentioned pH to its concentration is 1015gL
-1(with Na
2crO
44H
2o meter), water cooling crystallization, when crystal solution temperature is reduced to after 52 DEG C, centrifugation obtains 148.2kg Sodium chromate product.
In gained Sodium chromate product, the content of Sodium chromate is that 98.7 % by weight are (with Na
2crO
44H
2o meter), vitriol is that 0.21 % by weight is (with SO
4 2-meter), chlorine root is that 0.05 % by weight is (with Cl
-meter).
Embodiment 3
By 1.0m
3the Sodium chromate basic solution obtaining by roasting chromite and leaching is heated to 95 DEG C and keep constant, and wherein the concentration of Sodium chromate basic solution is 517gL
-1(with Na
2crO
44H
2o meter).
Under stirring by 1800m
3wherein gas concentration lwevel is that the chromite oxidizing roasting rotary kiln tail gas of approximately 12 volume % passes in Sodium chromate basic solution, until the pH of described solution is reduced to 9.4, then uses plate-and-frame filter press press filtration, obtains the solution of transparent clear.
In the solution that is 9.4 to above-mentioned pH, add 0.1m
3producing the electrolytic solution in sodium dichromate process from carborization, is 8.0 by the pH regulator of described solution, and wherein the concentration of electrolytic solution is 983gL
-1(with Na
2cr
2o
72H
2o meter), pH is 0.8.
The solution evaporation that is 8.0 by above-mentioned pH to its concentration is 961gL
-1(with Na
2crO
44H
2o meter), water cooling crystallization, when crystal solution temperature is reduced to after 28 DEG C, centrifugation obtains 180kg Sodium chromate product.
In gained Sodium chromate product, the content of Sodium chromate is that 98.5 % by weight are (with Na
2crO
42H
4o meter), vitriol is that 0.15 % by weight is (with SO
4 2-meter), chlorine root is that 0.10 % by weight is (with Cl
-meter).
Claims (7)
1. prepare a method for Sodium chromate, described method comprises:
I utilizes carbon dioxide or wraps carbonated gas by the Sodium chromate basic solution neutralization obtaining by roasting chromite and leaching;
Wherein utilize carbonic acid gas that Sodium chromate basic solution is neutralized to pH for 8.5-9.5;
II separates and removes solid impurity; With
III adds acid chromium-containing solution to regulate pH in the separating obtained solution of Step II;
Wherein utilizing acid chromium-containing solution is 7.0-8.5 by pH regulator;
Wherein, before carrying out step I, the temperature of Sodium chromate basic solution is controlled between 90-105 DEG C.
2. according to the process of claim 1 wherein that the carbonated gas of bag is the tail gas from Industrial Stoves.
3. according to the method for claim 2, wherein in the tail gas from Industrial Stoves, the content of carbonic acid gas is 1-99 volume %.
4. according to the method for any one in claim 1-3, wherein acid chromium-containing solution is that carborization is prepared the pre-carbodiimide solution, carbodiimide solution, electrolytic solution, dehydration mother liquor, waste water, wash water or its any mixing solutions that in sodium dichromate process, produce.
5. according to the method for any one in claim 1-4, described method also comprises:
IV concentrates Step II I gained solution by evaporation, so that its concentration is controlled at Na
2crO
44H
2o counts 900-1100gL
-1.
6. according to the method for claim 5, described method also comprises:
Step IV gained solution is cooled to 26-68 DEG C by V, so that Sodium chromate crystallization.
7. prepare a method for Sodium chromate, described method comprises:
I utilizes carbon dioxide or wraps carbonated gas the Sodium chromate basic solution obtaining by roasting chromite and leaching is neutralized to pH for 8.5-9.5;
II separates and removes solid impurity;
III is 7.0-8.5 to adding acid chromium-containing solution in the separating obtained solution of Step II by its pH regulator;
IV concentrates Step II I gained solution by evaporation, so that its concentration is controlled at Na
2crO
44H
2o counts 900-1100gL
-1; With
Step IV gained solution is cooled to 26-68 DEG C by V, so that Sodium chromate crystallization;
Wherein, before carrying out step I, the temperature of Sodium chromate basic solution is controlled between 90-105 DEG C; Wrapping carbonated gas is the tail gas from Industrial Stoves, and its carbon dioxide content is 1-99 volume %; Acid chromium-containing solution is that carborization is prepared the pre-carbodiimide solution, carbodiimide solution, electrolytic solution, dehydration mother liquor, waste water, wash water or its any mixing solutions that in sodium dichromate process, produce.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201210482808.9A CN102910678B (en) | 2012-11-23 | 2012-11-23 | Method for preparing sodium chromate |
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| CN103668301B (en) * | 2013-12-11 | 2016-08-24 | 中国科学院青海盐湖研究所 | Electrolysis is utilized to prepare the apparatus and method of chromium acid sodium solution |
| CN104843790B (en) * | 2015-05-22 | 2016-11-30 | 四川省银河化学股份有限公司 | A kind of chromite oxidizing method preparing sodium chromate of acid |
| CN106629849B (en) * | 2016-12-27 | 2017-11-14 | 四川省银河化学股份有限公司 | The method for preparing anhydrous sodium chromate |
| CN108910950B (en) * | 2018-10-12 | 2020-12-01 | 成都铬科高化工技术有限责任公司 | Method for preparing sodium chromate from chromite |
| CN112158885A (en) * | 2020-10-12 | 2021-01-01 | 甘肃锦世化工有限责任公司 | Method for reducing trivalent chromium in sodium dichromate acidizing fluid |
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| CN102642870A (en) * | 2011-06-09 | 2012-08-22 | 四川省安县银河建化（集团）有限公司 | Method for continuously neutralizing and decontaminating sodium chromate alkali solution |
| CN102649584A (en) * | 2011-08-22 | 2012-08-29 | 四川省安县银河建化（集团）有限公司 | Preparation method of sodium bichromate |
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| CN102649584A (en) * | 2011-08-22 | 2012-08-29 | 四川省安县银河建化（集团）有限公司 | Preparation method of sodium bichromate |
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