CN116002641A - Method for preparing phosphate by removing impurities and purifying through chemical precipitation method - Google Patents
Method for preparing phosphate by removing impurities and purifying through chemical precipitation method Download PDFInfo
- Publication number
- CN116002641A CN116002641A CN202211727077.XA CN202211727077A CN116002641A CN 116002641 A CN116002641 A CN 116002641A CN 202211727077 A CN202211727077 A CN 202211727077A CN 116002641 A CN116002641 A CN 116002641A
- Authority
- CN
- China
- Prior art keywords
- phosphoric acid
- phosphate
- impurity
- purifying
- chemical precipitation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Removal Of Specific Substances (AREA)
Abstract
The invention discloses a method for preparing phosphate by removing impurities and purifying by a chemical precipitation method, which comprises the following steps: s1, taking an impurity phosphoric acid solution, regulating the pH to 2.5-6.0, carrying out a neutralization reaction, and then carrying out solid-liquid separation; s2, adding a first precipitant into the solution obtained after the solid-liquid separation in the step S1 for reaction, and then carrying out solid-liquid separation; s3, adding the solution obtained after the solid-liquid separation in the step S2 into a second precipitator for reaction, and then carrying out solid-liquid separation to obtain a purified phosphate solution. The application adopts a chemical precipitation method with very simple operation steps, and prepares the battery-grade phosphate by taking the impurity phosphoric acid as a raw material, thereby not only ensuring the content and the utilization rate of phosphate radicals, but also reducing the influence of F, ca, mn, mg, al, zn and other impurity elements in the phosphate on the quality of the phosphate, and ensuring the supply of the phosphate source material of the ferric phosphate precursor.
Description
Technical Field
The invention belongs to the technical field of lithium ion battery anode material precursors, and particularly relates to a method for preparing phosphate by removing impurities and purifying by a chemical precipitation method.
Background
With the continuous development of human society industrialization, the excessive exploitation of mineral resources such as coal, petroleum and the like seriously pollutes the environment on which people depend to live, and brings human beings into an energy crisis age. Therefore, the development of new energy sources for environmental protection is an important point of research in various countries. The requirement of the phosphoric acid raw material is important for the production of the precursor ferric phosphate of the positive electrode material, and if the impurity phosphoric acid with relatively low cost is used for guaranteeing, the cost can be saved for the company.
The commercial impurity phosphoric acid mainly comes from enterprises which have phosphorite resources and are integrated with industrial chains in a layout mode, such as Hubei, sichuan, yunnan and Guizhou. The mass percentage of the phosphoric acid is about 60-65%, and the balance of the phosphoric acid contains more aluminum ions, fluorine ions, magnesium ions, iron ions, sodium ions, potassium ions and the like.
At present, phosphoric acid produced industrially is mainly wet-process phosphoric acid, but the impurity in the wet-process phosphoric acid is more, and the phosphoric acid needs to be deeply purified before being used. The main technology of wet phosphoric acid purification is as follows: solvent extraction, crystallization, electrodialysis, chemical precipitation, etc. However, the above methods have certain drawbacks, in which the solvent extraction method: the extraction process has a certain solvent loss, the process flow is complex, the cost is high, the extraction rate and the utilization rate of the extracted acid are required to be improved, and the like; crystallization method: the purification process by the crystallization method mostly belongs to an intermittent process, and has lower production efficiency, lower product yield and the like; electrodialysis method: when the wet phosphoric acid is purified by the electrodialysis method, only dilute phosphoric acid can be treated, phosphoric acid with higher concentration can not be treated, membrane holes are easy to be blocked, and SO is difficult to separate 4 2- Ions, the treatment cost is high; chemical precipitation: the purification depth is not enough, other impurity ions can be introduced, the difficulty of purification is increased, and the like; but has low control requirement on operation, simple process flow and less investment, thus the chemical precipitationThe purification of wet-process phosphoric acid by precipitation is still favored by many people.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provides a method for preparing phosphate by removing impurities and purifying by a chemical precipitation method.
The invention aims at realizing the following technical scheme:
a method for preparing phosphate by removing impurities and purifying by a chemical precipitation method comprises the following steps:
s1, taking an impurity phosphoric acid solution, regulating the pH to 2.5-6.0, carrying out a neutralization reaction, and then carrying out solid-liquid separation;
s2, adding a first precipitant into the solution obtained after the solid-liquid separation in the step S1 for reaction, and then carrying out solid-liquid separation; the first precipitant is any one or more than two of oxalic acid, potassium oxalate, sodium fluoride and tartaric acid;
s3, adding a second precipitant into the solution obtained after the solid-liquid separation in the step S2 for reaction, and then carrying out solid-liquid separation to obtain a purified phosphate solution; the second precipitant is any one or more than two selected from white carbon black, magnesium chloride, ferric chloride and lime.
Preferably, the impurity phosphoric acid solution in the step S1 is obtained by mixing impurity phosphoric acid and purified water, wherein the mass percentage of phosphoric acid in the impurity phosphoric acid is 60-65%; the mixing mass ratio of the impurity phosphoric acid and the purified water is (1-1.5): 1.
Preferably, the first precipitant is used in an amount of 10 to 50g per L of impurity phosphoric acid.
Preferably, the second precipitant is used in an amount of 5 to 30g per L of impurity phosphoric acid.
Preferably, the pH adjustment in step S1 is performed by using any one or a combination of two or more selected from sodium hydroxide, sodium carbonate, and ammonia water.
Preferably, the reaction temperature in the step S1 is 50-80 ℃.
Preferably, the reaction temperature in the step S2 is 50-80 ℃.
Preferably, the reaction temperature in the step S3 is 50-80 ℃.
Preferably, the reaction time of steps S1 to S3 is 30 to 60 minutes.
The application adopts a chemical precipitation method with very simple operation steps, and prepares the battery-grade phosphate by taking the impurity phosphoric acid as a raw material, thereby not only ensuring the content and the utilization rate of phosphate radicals, but also reducing the influence of F, ca, mn, mg, al, zn and other impurity elements in the phosphate on the quality of the phosphate, and ensuring the supply of the phosphate source material of the ferric phosphate precursor.
Detailed Description
The invention provides a method for preparing phosphate by removing impurities and purifying by a chemical precipitation method, which comprises the following steps:
s1, taking an impurity phosphoric acid solution, regulating the pH to 2.5-6.0, carrying out a neutralization reaction, and then carrying out solid-liquid separation;
s2, adding a first precipitant into the solution obtained after the solid-liquid separation in the step S1 for reaction, and carrying out solid-liquid separation; the first precipitant is any one or more than two of oxalic acid, potassium oxalate, sodium fluoride and tartaric acid;
s3, adding a second precipitant into the solution obtained after the solid-liquid separation in the step S2 for reaction, and carrying out solid-liquid separation to obtain a purified phosphate solution; the second precipitant is any one or more than two of white carbon black, magnesium chloride, ferric chloride and lime.
The method comprises the steps of firstly neutralizing an impurity phosphoric acid solution, and precipitating and removing part of impurity ions such as magnesium ions and iron ions in the form of phosphate double salt while forming phosphate, wherein the phosphate still contains high content of aluminum ions and fluorine ions; and then sequentially adopting a first precipitant and a second precipitant to remove aluminum and fluorine, wherein the impurity removal mechanism related to the first precipitant and the second precipitant is as follows:
first precipitant Al removal mechanism:
1) Oxalic acid Al removal mechanism:
2Al+3HOOC-COOH＝Al 2 (C 2 O4) 3 +3H 2 ↑
the mechanism of removing Al by potassium oxalate is similar to that of oxalic acid, and tartaric acid can also form aluminum salt precipitate to remove Al ions.
2) Sodium fluoride Al removal mechanism:
4AI(OH) 3 +6NaF＝＝＝Na 3 AIF 6 +3NaAlO 2 +6H 2 O
second precipitant F removal mechanism:
1) White carbon F-removing mechanism
6HF+SiO 2 ＝H 2 SiF 6 +2H 2 O (1)
H 2 SiF 6 ＝SiF 4 ↑+2HF (2)
2H 2 SiF 6 +SiO 2 ＝ 3SiF 4 ↑+2H 2 O (3)
2Na + (K + )+SiO 6 2- ＝Na(K) 2 SiF 6 (4)
2) Lime F removal mechanism
CaO + H 2 O ＝ Ca(OH) 2 ＝ Ca 2+ + 2OH - (1)
Ca 2+ + 2F - ＝ CaF 2 (2)
Magnesium chloride and ferric chloride can be used for generating magnesium fluoride and ferric fluoride precipitate together with fluorine ions, and the fluorine ions are removed.
The application adopts a chemical precipitation method with very simple operation steps, and prepares the battery-grade phosphate by taking the impurity phosphoric acid as a raw material, thereby not only ensuring the content and the utilization rate of phosphate radicals, but also reducing the influence of F, ca, mn, mg, al, zn and other impurity elements in the phosphate on the quality of the phosphate, and ensuring the supply of the phosphate source material of the ferric phosphate precursor.
Preferably, the step S1 impurity phosphoric acid solution is obtained by mixing impurity phosphoric acid and purified water, wherein the mass percentage of phosphoric acid in the impurity phosphoric acid is 60-65%, and the mass ratio of the impurity phosphoric acid to the purified water is (1-1.5): 1. The commercial impurity phosphoric acid has higher concentration, the phosphoric acid has higher viscosity, and the direct purification and impurity removal effects are not ideal, so that the phosphoric acid is favorable for subsequent reaction after being diluted.
Preferably, the first precipitant is used in an amount of 10 to 50g per L of impurity phosphoric acid (excluding purified water); the second precipitant is used in an amount of 5-30 g per L of impurity phosphoric acid (excluding purified water).
Preferably, the pH adjustment in the step S1 adopts any one or more than two of sodium hydroxide, sodium carbonate and ammonia water, and is added in a solution form during adjustment, wherein the mass fraction of solute in the solution is 20-50%.
Preferably, the reaction temperature of the steps S1 to S3 is 50-80 ℃ and the reaction time is 30-60 min. The reaction is facilitated at a certain high temperature.
Example 1
S1, taking commercially available impurity phosphoric acid (the mass percent of phosphoric acid is 62.3%, the mass percent of the impurity is shown in table 1), diluting with purified water, the mass ratio of the impurity phosphoric acid to the purified water is 1:1, adding a sodium hydroxide solution with the mass percent of 30%, adjusting the pH value to 4.0, carrying out neutralization reaction at 65 ℃ for 30min, and filtering;
s2, adding 35g/L oxalic acid into the filtrate obtained in the step S1, reacting for 40min at 65 ℃, and filtering;
s3, adding 25g/L white carbon black into the filtrate obtained in the step S2, reacting for 40min at 65 ℃, and filtering to obtain the filtrate, namely the purified phosphate solution.
The yield of P is reduced after chemical impurity removal and purification, and the loss rate of P is 20-25 percent. The final main impurity element Al has a removal rate of 99.4-99.6%, F has a removal rate of 98-99%, and Fe has a removal rate of 99.5-99.6%.
TABLE 1
Example 2
S1, diluting commercially available impurity phosphoric acid (same as in example 1) by using purified water, wherein the mass ratio of the impurity phosphoric acid to the purified water is 1.2:1, adding a sodium hydroxide solution with the mass fraction of 25%, adjusting the pH value to 2.5, carrying out neutralization reaction for 30min at 80 ℃, and filtering;
s2, adding sodium fluoride (25 g/L) into the filtrate obtained in the step S1, reacting at 60 ℃ for 30min, and filtering;
s3, lime (15 g/L) is added into the filtrate obtained in the step S2, the reaction is carried out for 30min at 60 ℃, and the filtrate is filtered, namely the purified phosphate solution.
Example 3
S1, diluting commercially available impurity phosphoric acid by using purified water, wherein the mass ratio of the impurity phosphoric acid to the purified water is 1:1, adding a 32% sodium hydroxide solution, adjusting the pH to 4.6, carrying out neutralization reaction at 80 ℃ for 50min, and filtering;
s2, adding sodium fluoride (45 g/L) into the filtrate obtained in the step S1, reacting for 40min at 65 ℃, and filtering;
s3, adding white carbon black (10 g/L) into the filtrate obtained in the step S2, reacting for 40min at 65 ℃, and filtering to obtain the filtrate, namely the purified phosphate solution.
Example 4
S1, diluting commercially available impurity phosphoric acid by using purified water, wherein the mass ratio of the impurity phosphoric acid to the purified water is 1.2:1, adding a sodium hydroxide solution with the mass fraction of 45%, adjusting the pH value to 6, carrying out neutralization reaction at 60 ℃ for 40min, and filtering;
s2, adding potassium oxalate (30 g/L) into the filtrate obtained in the step S1, reacting at 80 ℃ for 30min, and filtering;
s3, adding ferric chloride (20 g/L) into the filtrate obtained in the step S2, reacting for 30min at 80 ℃, and filtering to obtain the filtrate, namely the purified phosphate solution.
Comparative example 1
S1, taking commercially available impurity phosphoric acid (the mass percent of phosphoric acid is 62.3%, the impurity content is shown in table 1), diluting with purified water, the volume ratio of the impurity phosphoric acid to the purified water is 1:1, adding a 32% sodium hydroxide solution, adjusting the pH value to 4.6, carrying out neutralization reaction at 80 ℃ for 50min, and filtering;
s2, adding sodium fluoride (45 g/L) into the filtrate obtained in the step S1, reacting for 40min at 65 ℃, and filtering;
s3, adding white carbon black (10 g/L) into the filtrate obtained in the step S2, reacting for 40min at 65 ℃, and filtering to obtain the filtrate, namely the purified phosphate solution.
This comparative example compared to example 3, the volume ratio of the impurity phosphoric acid to purified water was changed to 1:1, the other conditions are unchanged. It was found that the sample was a viscous, gel-like liquid after the addition of sodium fluoride, which was not suction filtered, and subsequently tested with a mass ratio of 1:1.
Comparative example 2
S1, taking commercially available impurity phosphoric acid (the mass percent of phosphoric acid is 62.3%, the impurity content is shown in table 1), diluting with purified water, the mass ratio of the impurity phosphoric acid to the purified water is 1:1, adding a 32% sodium hydroxide solution, adjusting the pH value to 1.5, carrying out neutralization reaction at 80 ℃ for 50min, and filtering;
s2, adding sodium fluoride (45 g/L) into the filtrate obtained in the step S1, reacting for 40min at 65 ℃, and filtering;
s3, adding white carbon black (10 g/L) into the filtrate obtained in the step S2, reacting for 40min at 65 ℃, and filtering to obtain the filtrate, namely the purified phosphate solution.
In this comparative example, the pH was adjusted to 1.5 as compared with example 3, and the other conditions were unchanged. The results show that: the final main impurity element Al has 75-85%, F has 64-67%, fe has 70-75%, and the impurity removing rate is greatly reduced.
Comparative example 3
S1, taking commercially available impurity phosphoric acid (the mass percent of phosphoric acid is 62.3%, the impurity content is shown in table 1), diluting with purified water, the mass ratio of the impurity phosphoric acid to the purified water is 1:1, adding a 32% sodium hydroxide solution, adjusting the pH value to 4.6, carrying out neutralization reaction at 80 ℃ for 50min, and filtering;
s2, adding sodium fluoride (90 g/L) into the filtrate obtained in the step S1, reacting for 40min at 65 ℃, and filtering;
s3, adding white carbon black (10 g/L) into the filtrate obtained in the step S2, reacting for 40min at 65 ℃, and filtering to obtain the filtrate, namely the purified phosphate solution.
In this comparative example, sodium fluoride (90 g/L) was added in excess compared to example 3, with the other conditions unchanged. The results show that: excessive sodium fluoride increases the aluminum removal rate, but at the same time results in an increased content of F in the phosphorus salt. The final removal rate of the main impurity element Al is 99.9%, and the removal rate is improved by 0.03-0.05%; the removal rate of F is 85-90%, and the removal rate is reduced by 8-14%. Comprehensively considering, the impurity removing effect is reduced.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (9)
1. The method for preparing the phosphate by removing impurities and purifying by a chemical precipitation method is characterized by comprising the following steps of:
s1, taking an impurity phosphoric acid solution, regulating the pH to 2.5-6.0, carrying out a neutralization reaction, and then carrying out solid-liquid separation;
s2, adding a first precipitant into the solution obtained after the solid-liquid separation in the step S1 for reaction, and then carrying out solid-liquid separation; the first precipitant is any one or more than two of oxalic acid, potassium oxalate, sodium fluoride and tartaric acid;
s3, adding a second precipitant into the solution obtained after the solid-liquid separation in the step S2 for reaction, and then carrying out solid-liquid separation to obtain a purified phosphate solution; the second precipitant is any one or more than two selected from white carbon black, magnesium chloride, ferric chloride and lime.
2. The method for preparing phosphate by purifying and removing impurities by a chemical precipitation method according to claim 1,
the impurity phosphoric acid solution in the step S1 is obtained by mixing impurity phosphoric acid and purified water, wherein the mass percentage of phosphoric acid in the impurity phosphoric acid is 60-65%; the mixing mass ratio of the impurity phosphoric acid and the purified water is (1-1.5): 1.
3. The method for preparing phosphate by purifying and removing impurities by chemical precipitation method according to claim 2,
the dosage of the first precipitant is 10-50 g of phosphoric acid per L impurity.
4. The method for preparing phosphate by purifying and removing impurities by chemical precipitation method according to claim 2,
the dosage of the second precipitant is 5-30 g of phosphoric acid per L impurity.
5. The method for preparing phosphate by purifying and removing impurities by a chemical precipitation method according to claim 1,
and the pH adjustment in the step S1 adopts any one or more than two of sodium hydroxide, sodium carbonate and ammonia water.
6. The method for preparing phosphate by purifying and removing impurities by a chemical precipitation method according to claim 1,
the reaction temperature in the step S1 is 50-80 ℃.
7. The method for preparing phosphate by purifying and removing impurities by a chemical precipitation method according to claim 1,
the reaction temperature in the step S2 is 50-80 ℃.
8. The method for preparing phosphate by purifying and removing impurities by a chemical precipitation method according to claim 1,
the reaction temperature in the step S3 is 50-80 ℃.
9. The method for preparing phosphate by purifying and removing impurities by a chemical precipitation method according to claim 1,
the reaction time of the steps S1 to S3 is 30 to 60 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211727077.XA CN116002641A (en) | 2022-12-30 | 2022-12-30 | Method for preparing phosphate by removing impurities and purifying through chemical precipitation method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211727077.XA CN116002641A (en) | 2022-12-30 | 2022-12-30 | Method for preparing phosphate by removing impurities and purifying through chemical precipitation method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116002641A true CN116002641A (en) | 2023-04-25 |
Family
ID=86029444
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211727077.XA Pending CN116002641A (en) | 2022-12-30 | 2022-12-30 | Method for preparing phosphate by removing impurities and purifying through chemical precipitation method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116002641A (en) |
-
2022
- 2022-12-30 CN CN202211727077.XA patent/CN116002641A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112142081B (en) | Method for preparing battery-grade lithium carbonate by using lepidolite | |
| CN112939090B (en) | Manganese sulfate purification and crystallization method | |
| CN102070198A (en) | Method for preparing high-purity manganese sulfate and high-purity manganese carbonate by reduction leaching of pyrolusite through scrap iron | |
| WO2016029613A1 (en) | Method and apparatus for purifying desulfurization lead plaster filtrate | |
| CN105600763A (en) | Method for producing industrial monoammonium phosphate through fluoride salt purification method | |
| CN103991882A (en) | Method for preparing potassium fluoride by using fluoride in liquid phase of wet process phosphoric acid | |
| CN114524572B (en) | Comprehensive treatment method for wastewater generated in iron phosphate production | |
| CN111086977B (en) | Method for preparing MCP and MDCP (Madin-Darby Canine phosphate) by using raffinate acid | |
| US20220384868A1 (en) | Battery-level ni-co-mn mixed solution and preparation method for battery-level mn solution | |
| CN113443639B (en) | Preparation process of electronic grade potassium hydroxide | |
| CN112897544B (en) | Method for producing high-purity borax from boron-containing wastewater discharged in production of lithium carbonate in salt lake | |
| JP3151182B2 (en) | Copper electrolyte cleaning method | |
| CN110759364A (en) | Method for preparing high-purity lithium carbonate by using crude lithium phosphate | |
| CN116002641A (en) | Method for preparing phosphate by removing impurities and purifying through chemical precipitation method | |
| CN106637295A (en) | Purifying method for process of preparing electrolytic manganese metal electrolyte | |
| CN115927884A (en) | Defluorination method for rare earth ore leaching solution | |
| CN114262089A (en) | Method for recycling and treating aluminum anodic oxidation wastewater containing phosphoric acid and sulfuric acid | |
| CN113582206A (en) | Method for recovering and preparing crude lithium carbonate from battery material raffinate | |
| CN112250090A (en) | Production method for deeply removing fluorine in lithium sulfate solution | |
| CN1042445C (en) | Prepn. of pure tungstate by extracting tungsten from alkali leaching liquor of tungten ore | |
| CN107337299B (en) | Defluorination water purifying agent and preparation method thereof | |
| CN111573890A (en) | Comprehensive utilization method of ammonium chloride wastewater | |
| CN1475443A (en) | Method of producing neutral high quality anhydrous sodium sulfate using natucal salt lake sodium sulfate decahydrate | |
| CN219972063U (en) | Treatment system for waste water in iron phosphate production | |
| CN112794299B (en) | Method for preparing ferrous phosphate by using wet-process phosphoric acid |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |