CN116462173A - Method for preparing ferric phosphate by iron method - Google Patents
Method for preparing ferric phosphate by iron method Download PDFInfo
- Publication number
- CN116462173A CN116462173A CN202310641290.7A CN202310641290A CN116462173A CN 116462173 A CN116462173 A CN 116462173A CN 202310641290 A CN202310641290 A CN 202310641290A CN 116462173 A CN116462173 A CN 116462173A
- Authority
- CN
- China
- Prior art keywords
- iron
- ferric phosphate
- ferrous
- solution
- dihydrogen phosphate
- 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
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 title claims abstract description 264
- 229910052742 iron Inorganic materials 0.000 title claims abstract description 128
- 238000000034 method Methods 0.000 title claims abstract description 72
- 239000005955 Ferric phosphate Substances 0.000 title claims abstract description 71
- 229940032958 ferric phosphate Drugs 0.000 title claims abstract description 71
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 title claims abstract description 71
- 229910000399 iron(III) phosphate Inorganic materials 0.000 title claims abstract description 71
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 claims abstract description 88
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 76
- 238000005406 washing Methods 0.000 claims abstract description 69
- CWYNVVGOOAEACU-UHFFFAOYSA-N Fe2+ Chemical compound [Fe+2] CWYNVVGOOAEACU-UHFFFAOYSA-N 0.000 claims abstract description 61
- NBIIXXVUZAFLBC-UHFFFAOYSA-M dihydrogenphosphate Chemical compound OP(O)([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-M 0.000 claims abstract description 55
- 229910000147 aluminium phosphate Inorganic materials 0.000 claims abstract description 44
- 239000012065 filter cake Substances 0.000 claims abstract description 39
- 239000007788 liquid Substances 0.000 claims abstract description 30
- 238000006243 chemical reaction Methods 0.000 claims abstract description 29
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 29
- 239000002002 slurry Substances 0.000 claims abstract description 22
- 238000001354 calcination Methods 0.000 claims abstract description 17
- 238000001035 drying Methods 0.000 claims abstract description 17
- 230000005484 gravity Effects 0.000 claims abstract description 16
- 238000001914 filtration Methods 0.000 claims abstract description 10
- 239000002994 raw material Substances 0.000 claims abstract description 10
- 230000001590 oxidative effect Effects 0.000 claims abstract description 9
- 238000000926 separation method Methods 0.000 claims abstract description 8
- -1 dihydrate ferric phosphate Chemical class 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims abstract description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 39
- 238000002844 melting Methods 0.000 claims description 27
- 230000008018 melting Effects 0.000 claims description 26
- 239000012452 mother liquor Substances 0.000 claims description 20
- 239000002253 acid Substances 0.000 claims description 14
- 229910052698 phosphorus Inorganic materials 0.000 claims description 11
- 230000003647 oxidation Effects 0.000 claims description 9
- 230000001502 supplementing effect Effects 0.000 claims description 9
- 238000002360 preparation method Methods 0.000 claims description 6
- 238000005259 measurement Methods 0.000 claims description 5
- 239000000047 product Substances 0.000 abstract description 13
- 239000003513 alkali Substances 0.000 abstract description 8
- 229910000398 iron phosphate Inorganic materials 0.000 abstract description 8
- 230000007613 environmental effect Effects 0.000 abstract description 2
- 229910019142 PO4 Inorganic materials 0.000 abstract 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 abstract 1
- 239000010452 phosphate Substances 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 58
- 230000001276 controlling effect Effects 0.000 description 17
- 238000003825 pressing Methods 0.000 description 11
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000001105 regulatory effect Effects 0.000 description 7
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- BMTOKWDUYJKSCN-UHFFFAOYSA-K iron(3+);phosphate;dihydrate Chemical compound O.O.[Fe+3].[O-]P([O-])([O-])=O BMTOKWDUYJKSCN-UHFFFAOYSA-K 0.000 description 6
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 6
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000011161 development Methods 0.000 description 5
- 239000010413 mother solution Substances 0.000 description 5
- 239000011574 phosphorus Substances 0.000 description 5
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 4
- 238000004146 energy storage Methods 0.000 description 4
- 239000012535 impurity Substances 0.000 description 4
- VCJMYUPGQJHHFU-UHFFFAOYSA-N iron(3+);trinitrate Chemical compound [Fe+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O VCJMYUPGQJHHFU-UHFFFAOYSA-N 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 229910017604 nitric acid Inorganic materials 0.000 description 4
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
- 239000010405 anode material Substances 0.000 description 3
- 229910052744 lithium Inorganic materials 0.000 description 3
- DPTATFGPDCLUTF-UHFFFAOYSA-N phosphanylidyneiron Chemical compound [Fe]#P DPTATFGPDCLUTF-UHFFFAOYSA-N 0.000 description 3
- 239000007774 positive electrode material Substances 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- 239000007864 aqueous solution Substances 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- 239000011790 ferrous sulphate Substances 0.000 description 2
- 235000003891 ferrous sulphate Nutrition 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 239000002440 industrial waste Substances 0.000 description 2
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 2
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- BYJJYQFSLKYEFR-UHFFFAOYSA-N OP(O)(O)=O.OP(O)(O)=O.OP(O)(O)=O.P Chemical compound OP(O)(O)=O.OP(O)(O)=O.OP(O)(O)=O.P BYJJYQFSLKYEFR-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000012824 chemical production Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012983 electrochemical energy storage Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000000411 inducer Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 150000004698 iron complex Chemical class 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 239000011232 storage material Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
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
Abstract
The invention discloses a method for preparing ferric phosphate by an iron method, which comprises the following steps of 1) dissolving iron, and placing excessive pure iron into dilute phosphoric acid for an iron dissolving reaction; continuously reacting for 6-14 h, wherein the concentration of the dilute phosphoric acid solution is 16-30%; obtaining ferrous dihydrogen phosphate solution; 2) Detecting, namely adjusting the specific gravity of ferrous diammine phosphate solution; 3) Oxidizing, namely mixing the adjusted ferrous dihydrogen phosphate solution with hydrogen peroxide after filtering, controlling the hydrogen peroxide feeding time to be 30-80 min, and carrying out an oxidation reaction for 1-3 h to obtain ferric phosphate dihydrate slurry; 4) Carrying out solid-liquid separation on the ferric phosphate dihydrate slurry, and carrying out multistage countercurrent washing on a filter cake to obtain ferric phosphate dihydrate; 5) And drying and calcining the dihydrate ferric phosphate to obtain the ferric phosphate. The method directly uses high-purity iron to react with phosphoric acid to prepare ferrous iron phosphate, and hydrogen peroxide is oxidized to obtain ferric phosphate, so that the PH is not required to be adjusted by adding alkali in the whole process; simple process, environmental protection, high product purity and high utilization rate of raw materials.
Description
Technical Field
The invention relates to the technical field of chemical production, in particular to a method for preparing ferric phosphate by an iron method.
Background
Along with the shortage of energy and the increasing serious environmental pollution, new energy has become an important direction of future development, and lithium battery materials are highly valued and supported as important links of new energy industries, and represent a rapid development situation in recent years, thereby bringing about great market demands for lithium batteries. The lithium battery material is used as a power battery material of a new energy automobile and an electrochemical energy storage 'core', and plays an extremely important role in the surge of new energy automobile industrialization. At present, the lithium iron phosphate serving as a positive electrode energy storage material of the power and energy storage battery has obvious comprehensive advantages, outstanding safety performance and cycle life advantages, reduced cost caused by mass production, and the lithium iron phosphate material has become a first-choice positive electrode material of the power battery and the energy storage battery of a novel automobile.
Along with the rapid development of the lithium iron phosphate anode material, the ferric phosphate is used as a precursor of the lithium iron phosphate of the battery anode material, is a main raw material for producing the lithium iron phosphate anode material, and the application of the lithium iron phosphate battery mainly comprises the application of the new energy automobile industry, the application of the energy storage market, the application on a starting power supply and the like, wherein the standard is the largest, and the most application is the new energy automobile industry. The new energy automobile industry taking a lithium ion battery as an energy system has entered a blowout type development stage, the demand of the positive electrode material of the power battery is increased in an explosive manner, and the precursor of the positive electrode material is rapidly developed in the development stage.
The current process for producing ferric phosphate by ferrophosphorus synthesis is less, in particular to the process for using pure iron and phosphoric acid as raw materials, mainly because the phosphoric acid cannot be completely ionized, and Fe (H) generated by reaction 2 PO 4 ) 2 、FeHPO 4 Unstable. Aiming at the problem of unstable reaction products of phosphoric acid and iron, the existing solutions have the following steps:
firstly, high-purity iron reacts with nitric acid to prepare ferric nitrate and then reacts with phosphoric acid, and ferric phosphate and ferric nitrate are added to react as inducers to obtain ferric phosphate. However, nitric acid is an explosive product which is easy to produce and has strong corrosiveness, and has great potential safety hazards in storage and use in mass production.
Secondly, a preparation method of ferric phosphate is disclosed in patent CN202210160066.1, and the technology is that iron blocks are placed in phosphoric acid solution for iron melting treatment to obtain ferrous liquid, the ferrous liquid is mixed with hydrogen peroxide for oxidation reaction, and pH value is required to be regulated by alkali before the oxidation reaction. Before the ferrous solution oxidation reaction, the conventional means is to use alkali solution such as sodium hydroxide, ammonia water and the like to adjust the pH, but new impurity ions may be introduced into the reaction system, so that the quality of the product cannot be ensured, and the production time is prolonged.
Thirdly, the ferric phosphate is obtained by reacting the ferrous sulfate obtained by utilizing the reaction of the high-purity iron and the dilute sulfuric acid and then reacting the ferrous sulfate with the phosphoric acid, the sulfuric acid aqueous solution obtained by the method needs to replace sulfate radical by phosphoric acid and needs to be neutralized by alkali, so that a large amount of industrial waste liquid is caused, and the quality of the product is finally affected due to the introduction of sulfate radical impurities into a reaction system of the product.
Disclosure of Invention
The invention provides a method for preparing ferric phosphate by an iron method.
A method for preparing ferric phosphate by an iron method, comprising the following steps:
1) Dissolving iron, namely placing excessive pure iron into dilute phosphoric acid to perform an iron dissolving reaction; continuously reacting for 6-14 h, wherein the concentration of the dilute phosphoric acid solution is 16-30%; obtaining ferrous dihydrogen phosphate solution;
2) Detecting, namely measuring the Fe and P contents of the ferrous dihydrogen phosphate solution, performing acid supplementing operation on the ferrous dihydrogen phosphate solution according to a measurement result, and adjusting the specific gravity of the ferrous dihydrogen phosphate solution;
3) Oxidizing, namely mixing the adjusted ferrous dihydrogen phosphate solution with hydrogen peroxide after filtering, controlling the hydrogen peroxide feeding time to be 30-80 min, and carrying out an oxidation reaction for 1-3 h to obtain ferric phosphate dihydrate slurry;
4) Carrying out solid-liquid separation on the ferric phosphate dihydrate slurry, and carrying out multistage countercurrent washing on a filter cake to obtain ferric phosphate dihydrate;
5) And drying and calcining the dihydrate ferric phosphate to obtain the ferric phosphate.
As a preferable technical means, the temperature of the iron melting reaction in the step 1) is 65-95 ℃; the excessive pure iron is excessive pure iron with purity of more than 99.90 percent.
As a preferable technical means, the specific gravity of the ferrous dihydrogen phosphate solution after adjustment in the step 2) is 1.15-1.25 g/L.
As a preferable technical means, the molar ratio of Fe to P of the adjusted ferrous dihydrogen phosphate solution in the step 2) is 1:2.55-2.95.
As a preferable technical means, the concentration of the hydrogen peroxide in the step 3) is 18-27%, and the hydrogen peroxide is 1-2 times of the iron molar quantity in the ferrous dihydrogen phosphate solution.
As a preferable technical means, the oxidation reaction temperature in the 2) is 60 to 95 ℃.
As a preferable technical means, the P content in the mother liquor obtained after the solid-liquid separation of the 4) is 2% -4%, the mother liquor is used as a dilute phosphoric acid preparation raw material of the next iron melting, and the ratio of the mother liquor to 85% phosphoric acid is 1:0.5 to 1.
As a preferred technical means, the filter cake in 4) is subjected to a four-stage countercurrent washing, and the pH of the fourth-stage countercurrent washing water is more than 1.5.
The first-stage washing water of the fourth-stage countercurrent washing in the 4) is used for adjusting the next batch of ferrous dihydrogen phosphate solution to be matched with acid or the adjustment before the ferrous dihydrogen phosphate solution is oxidized, the second-stage washing water, the third-stage washing water and the fourth-stage washing water are sequentially used as a first-stage washing liquid, a second-stage washing liquid and a third-stage washing liquid of a next batch of filter cakes, and the fourth-stage washing liquid of the filter cakes is desalted water or pure water.
As a preferable technical means, the filter cake in the step 5) is dried at 105-160 ℃ for 30-80 min, and the filter cake is calcined at 500-800 ℃ for 4-6 h.
The method for preparing the ferric phosphate by adopting the technical scheme comprises the following steps of 1) ferric phosphate, and placing excessive pure iron into dilute phosphoric acid for ferric phosphate reaction; continuously reacting for 6-14 h, wherein the concentration of the dilute phosphoric acid solution is 16-30%; obtaining ferrous dihydrogen phosphate solution; 2) Detecting, namely measuring the Fe and P contents of the ferrous dihydrogen phosphate solution, performing acid supplementing operation on the ferrous dihydrogen phosphate solution according to a measurement result, and adjusting the specific gravity of the ferrous dihydrogen phosphate solution; 3) Oxidizing, namely mixing the adjusted ferrous dihydrogen phosphate solution with hydrogen peroxide after filtering, controlling the hydrogen peroxide feeding time to be 30-80 min, and carrying out an oxidation reaction for 1-3 h to obtain ferric phosphate dihydrate slurry; 4) Carrying out solid-liquid separation on the ferric phosphate dihydrate slurry, and carrying out multistage countercurrent washing on a filter cake to obtain ferric phosphate dihydrate; 5) And drying and calcining the dihydrate ferric phosphate to obtain the ferric phosphate.
The invention has the advantages that:
preparing ferrous iron phosphate by directly reacting high-purity iron with phosphoric acid, oxidizing hydrogen peroxide to obtain ferric phosphate, and adjusting the PH without adding alkali in the whole process; simple process, environmental protection, high product purity and high utilization rate of raw materials.
1. The method is used for industrial production of ferric phosphate, excessive iron is firstly used for reacting with dilute phosphoric acid, and then acid is supplemented in the step 2), so that the molar ratio of the ferrophosphorus in the ferrous dihydrogen phosphate solution can reach a proper range, and the adjusted ferrous dihydrogen phosphate solution can stably exist;
2. in industrialized mass production, excessive iron is adopted to react with dilute phosphoric acid, so that the operation is convenient, and the raw materials such as iron ingots, iron blocks and the like which are time-consuming and labor-consuming are not required to be added into a reaction container during each production;
3. in the invention, acid is used for supplementing phosphorus instead of alkali liquor for regulating the pH value, the molar ratio of phosphorus to iron in the phosphorus dihydrogen phosphate solution after phosphorus supplementing can reach a proper range, and ammonia water or sodium hydroxide and other alkali liquor are not needed for regulating the pH value, so that new impurities are prevented from being introduced into a reaction system;
4. in the invention, dilute sulfuric acid and dilute nitric acid are not needed to react with iron, so that nitric acid which is not easy to store for a long time in a large scale is avoided in industrial production, sulfate radical impurities are avoided to be introduced into a reaction system, and a large amount of subsequent industrial waste liquid such as sulfuric acid aqueous solution and the like is avoided during the treatment of sulfate radical.
5. After the reaction of excessive iron and dilute phosphoric acid is adopted, the reaction end point is well controlled, and the detection of the Fe and P content of the ferrous dihydrogen phosphate in the step 2) is determined by adopting a titration method after only one sampling, so that the processing time is saved; after the iron melting is finished, the iron-phosphorus ratio in the ferrous dihydrogen phosphate solution is generally 1:2.3 to 2.5, the iron-phosphorus ratio in the adjusted ferrous dihydrogen phosphate solution is controlled to be 1:2.55 to 2.95; therefore, in the acid supplementing process when the iron-phosphorus ratio is regulated, a large amount of time is not required to be spent for supplementing a large amount of acid, and compared with the industrial pH value regulation, the method is more beneficial to saving the processing and production time; the specific gravity of the adjusted ferrous dihydrogen phosphate solution only ranges from 1.1500 g/L to 1.25g/L, the iron concentration of the adjusted ferrous dihydrogen phosphate solution reaches the target range, the iron concentration of the adjusted ferrous dihydrogen phosphate solution exceeds the target range, the quality of the adjusted ferrous dihydrogen phosphate solution is changed, namely the adjusted ferrous dihydrogen phosphate solution is deteriorated, and the normal oxidation operation cannot be performed subsequently.
6. The iron method ferric phosphate process adopted by the invention has simple process, no alkali liquor is required to be used for adjusting the pH in the whole process, and the washing liquor directly and circularly participates in the adjustment of the mixed dilute acid and ferrous dihydrogen phosphate solution, so that the water balance in the production process can be realized, the production energy consumption is greatly reduced, and the sewage treatment capacity is reduced.
Drawings
FIG. 1 is a process flow diagram of an iron phosphate process of the present invention;
FIG. 2 is an SEM image of iron phosphate according to the present invention.
Detailed Description
The invention provides a method for preparing ferric phosphate by an iron method, which aims to solve the problems in the prior art.
A method for preparing ferric phosphate by an iron method, comprising the following steps:
1) Dissolving iron, namely placing excessive pure iron into dilute phosphoric acid to perform an iron dissolving reaction; continuously reacting for 6-14 h, wherein the concentration of the dilute phosphoric acid solution is 16-30%; obtaining ferrous dihydrogen phosphate solution;
2) Detecting, namely measuring the Fe and P contents of the ferrous dihydrogen phosphate solution, performing acid supplementing operation on the ferrous dihydrogen phosphate solution according to a measurement result, and adjusting the specific gravity of the ferrous dihydrogen phosphate solution;
3) Oxidizing, namely mixing the adjusted ferrous dihydrogen phosphate solution with hydrogen peroxide after filtering, controlling the hydrogen peroxide feeding time to be 30-80 min, and carrying out an oxidation reaction for 1-3 h to obtain ferric phosphate dihydrate slurry;
4) Carrying out solid-liquid separation on the ferric phosphate dihydrate slurry, and carrying out multistage countercurrent washing on a filter cake to obtain ferric phosphate dihydrate;
5) And drying and calcining the dihydrate ferric phosphate to obtain the ferric phosphate.
The temperature of the iron melting reaction in the step 1) is 65-95 ℃; the excessive pure iron is excessive pure iron with purity of more than 99.90 percent.
The specific gravity of the ferrous dihydrogen phosphate solution after adjustment in the step 2) is 1.1500-1.25 g/L.
The molar ratio of Fe to P of the ferrous dihydrogen phosphate solution after adjustment in the step 2) is 1:2.55-2.95.
The concentration of hydrogen peroxide in the step 3) is 18-27%, and the hydrogen peroxide is 1-2 times of the molar quantity of iron in the ferrous dihydrogen phosphate solution.
The temperature of the oxidation reaction in the step 2) is 60-95 ℃.
The P content in the mother liquor obtained after the solid-liquid separation of the 4) is 2% -4%, the mother liquor is used as the dilute phosphoric acid preparation raw material of the next iron melting, and the ratio of the mother liquor to 85% phosphoric acid is 1:0.5 to 1.
And 4) carrying out four-stage countercurrent washing on the filter cake in the step 4), wherein the PH of fourth-stage washing water of the four-stage countercurrent washing is more than 1.5.
The first-stage washing water of the fourth-stage countercurrent washing in the step 4) is used for adjusting the next batch of ferrous dihydrogen phosphate solution to be matched with acid or the adjustment before the ferrous dihydrogen phosphate solution is oxidized, the second-stage washing water, the third-stage washing water and the fourth-stage washing water are sequentially used as the first-stage washing liquid, the second-stage washing liquid and the third-stage washing liquid of the next batch of filter cakes, and the fourth-stage washing liquid of the filter cakes is desalted water or pure water.
And 5) drying the filter cake at 105-160 ℃ for 30-80 min, and calcining the filter cake at 500-800 ℃ for 4-6 h.
The method is realized by the following technical scheme:
1) Continuously reacting excessive pure iron with purity of more than 99.90% with dilute phosphoric acid with concentration of 16% -30% at 65-95 ℃ for 6-14 h to generate ferrous dihydrogen phosphate solution;
2) Detecting the Fe and P contents of the ferrous dihydrogen phosphate solution, performing acid supplementing operation on the iron melting solution according to a measurement result, and controlling the Fe of the ferrous dihydrogen phosphate solution: p=1: 2.55 to 2.95 (molar ratio) of 1.1500 to 1.25g/L;
3) Filtering the ferrous dihydrogen phosphate solution, adding 18-27% hydrogen peroxide which is 1-2 times of the molar weight of iron in the ferrous dihydrogen phosphate solution, controlling the feeding time of the hydrogen peroxide to be 30-80 min, controlling the oxidation reaction temperature to be 60-95 ℃, and oxidizing for 1-3 h to obtain ferric phosphate dihydrate slurry;
4) Filter pressing washing treatment is carried out on the ferric phosphate slurry, a filter cake and a mother solution are separated, the P% of the mother solution is 2% -4%, the mother solution is stored and used as a dilute phosphoric acid preparation raw material for next iron melting, and the ratio of the mother solution to 85% phosphoric acid is 1:0.5 to 1, the iron melting time can be shortened by more than 30 percent; and (3) carrying out multistage countercurrent washing on the filter cake, controlling the pH value of the final-stage washing water to be more than 1.5, wherein the first-stage washing water can be used for adjusting the next batch of iron complex acid or ferrous dihydrogen phosphate solution before oxidation, and the second-fourth-stage washing water is sequentially used as the first-third washing liquid of the next batch of filter cake, and the fourth-stage washing liquid of the filter cake is desalted water or pure water.
5) And drying the filter cake reaching the washing standard at 105-160 ℃ and calcining at 500-800 ℃ to obtain anhydrous ferric phosphate.
The invention is further described in connection with the following embodiments in order to make the technical means, the creation features, the achievement of the purpose and the effect of the invention easy to understand.
Example 1:
1) And (3) an iron melting procedure: continuously reacting excessive pure iron with purity of more than 99.90% with dilute phosphoric acid with concentration of 16% -30% at 65-95 ℃ for 6-14 h to generate ferrous dihydrogen phosphate solution (hereinafter referred to as ferric liquid);
2) And (3) regulating molten iron melting: adjusting molten iron Fe: p=1: 2.55 to 2.95 molar ratio, and adjusting the specific gravity of the molten iron to 1.1500 to 1.25g/L;
3) Oxidation procedure: filtering the molten iron, adding 18-27% hydrogen peroxide which is 1-2 times of the molar quantity of iron in the molten iron, controlling the feeding time of the hydrogen peroxide to be 30-80 min, controlling the oxidation reaction temperature to be 60-95 ℃ and carrying out oxidation reaction for 1-3 h to obtain ferric phosphate dihydrate slurry;
4) And (3) a filter pressing washing procedure: carrying out filter pressing treatment on the iron phosphate slurry to separate a filter cake and a mother liquor, wherein the P% of the mother liquor is 2% -4%, the mother liquor is stored and used as a dilute phosphoric acid preparation raw material for next iron melting, and the ratio of the mother liquor to 85% phosphoric acid is 1:0.5 to 1, the iron melting time can be shortened by more than 30 percent; and (3) carrying out multistage countercurrent washing on the filter cake, controlling the PH of the final-stage washing water to be more than 1.5, and enabling each stage of washing water to participate in circulation according to requirements.
5) Drying and calcining: and drying the filter cake reaching the washing standard at 105-160 ℃ and calcining at 500-800 ℃ to obtain anhydrous ferric phosphate.
In the invention, excessive pure iron is placed in phosphoric acid solution for iron melting reaction, the iron melting solution is filtered and then subjected to phosphorus adjustment treatment according to the phosphorus content, and Fe is controlled: p=1: 2.55 to 2.95 (molar ratio) of controlling the specific gravity of the molten iron to 1.1500 to 1.25g/L; the phosphoric acid solution is preferably 85% phosphoric acid according to the ratio of mother solution to 85% phosphoric acid of 1:0.5 to 1. The iron melting temperature is preferably 80-95 ℃, and the iron melting time is preferably 8-12 h. The reaction involved in the iron-melting procedure is as follows:
Fe+2H 3 PO 4 →Fe(H 2 PO 4 ) 2 +H 2 ↑
the method mixes the iron melting liquid with hydrogen peroxide to perform oxidation reaction to obtain dihydrate ferric phosphate slurry. The hydrogen peroxide is preferably 27% of analytically pure hydrogen peroxide, and the mode of adding hydrogen peroxide is not limited. The temperature of the oxidation reaction is preferably 75-90 ℃, the reaction time is preferably 1.5-2.5 h, and the amount of hydrogen peroxide is 1-1.5 times of the molar amount of iron in the molten iron.
The slurry is subjected to filter pressing and washing, liquid obtained by the first filter pressing is called mother liquor, liquid obtained by washing of each subsequent stage is called washing liquid of each stage in sequence, and the obtained solid filter cake is ferric phosphate dihydrate. Preferably, the pH of the final wash solution is controlled to > 1.7.
The filter cake is dried and calcined, preferably, the drying temperature is 110-150 ℃ and the calcining temperature is 580-680 ℃.
Example 2:
and (3) an iron melting procedure: pure iron blocks are placed in the reaction kettle, 85 percent of concentrated phosphoric acid is slowly added into desalted water to prepare phosphoric acid solution with the concentration of 16 percent, the temperature of the reaction kettle is heated to 65 ℃, the temperature is kept for reaction for 14 hours,
and (3) an iron melting liquid adjusting procedure: adjusting molten iron Fe: p=1: 2.56 (molar ratio) adjusting the specific gravity of the molten iron to 1.05g/L;
oxidation procedure: filtering the molten iron, adding 18% hydrogen peroxide, wherein the molar quantity of the hydrogen peroxide is equal to that of iron in the molten iron, controlling the hydrogen peroxide feeding time to be 30min, controlling the oxidation reaction temperature to be about 60 ℃, and oxidizing for 1h to obtain ferric phosphate dihydrate slurry;
and (3) a filter pressing washing procedure: and carrying out filter pressing treatment on the iron phosphate slurry to separate a filter cake and mother liquor, wherein the P% of the mother liquor is 2.02%, and washing water PH of the filter cake after four-stage countercurrent washing is 2.02.
Drying and calcining: and drying the filter cake reaching the washing standard at 105 ℃ and calcining at 500 ℃ to obtain anhydrous ferric phosphate, wherein the yield is 96.5% (calculated according to the iron yield).
Example 3:
and (3) an iron melting procedure: pure iron blocks are placed in the reaction kettle, 85% of concentrated phosphoric acid is slowly added into desalted water to prepare phosphoric acid solution with concentration of 24%, the temperature of the reaction kettle is heated to 80 ℃, and the temperature is kept for reaction for 10 hours;
and (3) an iron melting liquid adjusting procedure: adjusting molten iron Fe: p=1: 2.71 (molar ratio) adjusting the specific gravity of the molten iron to 1.11g/L;
oxidation procedure: filtering the molten iron, adding hydrogen peroxide with the concentration of 20%, wherein the hydrogen peroxide is 1.10 times of the molar quantity of iron in the molten iron, controlling the feeding time of the hydrogen peroxide to be 40min, controlling the oxidation reaction temperature to be about 70 ℃, and carrying out oxidation reaction for 1.5h to obtain ferric phosphate dihydrate slurry;
and (3) a filter pressing washing procedure: and carrying out filter pressing treatment on the iron phosphate slurry to separate a filter cake and mother liquor, wherein the P% of the mother liquor is 2.51%, and washing water PH of the filter cake after four-stage countercurrent washing is 1.91.
Drying and calcining: and drying the filter cake reaching the washing standard at 110 ℃ and calcining at 600 ℃ to obtain anhydrous ferric phosphate, wherein the yield is 97.6% (calculated according to the iron yield).
Example 4:
and (3) an iron melting procedure: pure iron blocks are placed in the reaction kettle, 85% of concentrated phosphoric acid is slowly added into desalted water to prepare a phosphoric acid solution with the concentration of 30%, the temperature of the reaction kettle is heated to 95 ℃, and the temperature is kept for reaction for 6 hours;
and (3) an iron melting liquid adjusting procedure: adjusting molten iron Fe: p=1: 2.83 (molar ratio) adjusting the specific gravity of the molten iron to 1.15g/L;
oxidation procedure: filtering the molten iron, adding 25% hydrogen peroxide which is 1.15 times of the molar quantity of iron in the molten iron, controlling the feeding time of the hydrogen peroxide to be 50min, controlling the oxidation reaction temperature to be about 75 ℃, and oxidizing for 2.5h to obtain ferric phosphate dihydrate slurry;
and (3) a filter pressing washing procedure: and carrying out filter pressing treatment on the iron phosphate slurry to separate a filter cake and mother liquor, wherein the P% of the mother liquor is 3.12%, and the PH of washing water after four-stage countercurrent washing of the filter cake is 1.62.
Drying and calcining: and drying the filter cake reaching the washing standard at 110 ℃ and calcining at 650 ℃ to obtain anhydrous ferric phosphate, wherein the yield is 98.1 percent (calculated according to the iron yield).
Comparative example 1:
a finished iron phosphate dihydrate was prepared as in example 1, except that the temperature of the iron-dissolving reaction was changed to 50 ℃, and a light pink iron phosphate dihydrate product was finally obtained, with a yield of 95.2%.
Comparative example 2:
a final iron phosphate dihydrate product was prepared as in example 1, except that the hydrogen peroxide addition time in the oxidation step was changed to 15 minutes, resulting in a light pink iron phosphate dihydrate product with a yield of 96.4%.
Comparative example 3:
a final iron phosphate dihydrate product was prepared as in example 1, except that the hydrogen peroxide in the oxidation step was oxidized at 50℃to give a light pink iron phosphate dihydrate product with a yield of 98.3%.
Comparative example 4:
a finished product of ferric phosphate dihydrate was prepared as in example 1, except that in the molten iron adjustment step, molten iron Fe: p=1: 1 (molar ratio), and the specific gravity of the molten iron is regulated to be 0.5g/L; the yield was 30.2%.
Comparative example 5:
a finished product of ferric phosphate dihydrate was prepared as in example 1, except that in the molten iron adjustment step, molten iron Fe: p=1: 4 (molar ratio), wherein the specific gravity of the molten iron is regulated to be 1.5g/L; the yield was 60.5%.
The foregoing has shown and described the basic principles, main features and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. A method for preparing ferric phosphate by an iron method, which is characterized by comprising the following steps:
1) Dissolving iron, namely placing excessive pure iron into dilute phosphoric acid to perform an iron dissolving reaction; continuously reacting for 6-14 h, wherein the concentration of the dilute phosphoric acid solution is 16-30%; obtaining ferrous dihydrogen phosphate solution;
2) Detecting, namely measuring the Fe and P contents of the ferrous dihydrogen phosphate solution, performing acid supplementing operation on the ferrous dihydrogen phosphate solution according to a measurement result, and adjusting the specific gravity of the ferrous dihydrogen phosphate solution;
3) Oxidizing, namely mixing the adjusted ferrous dihydrogen phosphate solution with hydrogen peroxide after filtering, controlling the hydrogen peroxide feeding time to be 30-80 min, and carrying out an oxidation reaction for 1-3 h to obtain ferric phosphate dihydrate slurry;
4) Carrying out solid-liquid separation on the ferric phosphate dihydrate slurry, and carrying out multistage countercurrent washing on a filter cake to obtain ferric phosphate dihydrate;
5) And drying and calcining the dihydrate ferric phosphate to obtain the ferric phosphate.
2. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: the temperature of the iron melting reaction in the step 1) is 65-95 ℃; the excessive pure iron is excessive pure iron with purity of more than 99.90 percent.
3. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: the specific gravity of the ferrous dihydrogen phosphate solution after adjustment in the step 2) is 1.15-1.25 g/L.
4. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: the molar ratio of Fe to P of the ferrous dihydrogen phosphate solution after adjustment in the step 2) is 1:2.55-2.95.
5. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: the concentration of hydrogen peroxide in the step 3) is 18-27%, and the hydrogen peroxide is 1-2 times of the molar quantity of iron in the ferrous dihydrogen phosphate solution.
6. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: the temperature of the oxidation reaction in the step 2) is 60-95 ℃.
7. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: the P content in the mother liquor obtained after the solid-liquid separation of the 4) is 2% -4%, the mother liquor is used as the dilute phosphoric acid preparation raw material of the next iron melting, and the ratio of the mother liquor to 85% phosphoric acid is 1:0.5 to 1.
8. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: and 4) carrying out four-stage countercurrent washing on the filter cake in the step 4), wherein the PH of fourth-stage washing water of the four-stage countercurrent washing is more than 1.5.
9. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: the first-stage washing water of the fourth-stage countercurrent washing in the step 4) is used for adjusting one of the matching acid of the ferrous dihydrogen phosphate solution or the adjustment before the oxidation of the ferrous dihydrogen phosphate solution in the next batch, the second-stage washing water, the third-stage washing water and the fourth-stage washing water are sequentially used as the first-stage washing water, the second-stage washing water and the third-stage washing water of the next batch of filter cakes, and the fourth-stage washing water of the filter cakes is desalted water or pure water.
10. A method for preparing ferric phosphate by an iron method according to claim 1, wherein: and 5) drying the filter cake at 105-160 ℃ for 30-80 min, and calcining the filter cake at 500-800 ℃ for 4-6 h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310641290.7A CN116462173A (en) | 2023-06-01 | 2023-06-01 | Method for preparing ferric phosphate by iron method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310641290.7A CN116462173A (en) | 2023-06-01 | 2023-06-01 | Method for preparing ferric phosphate by iron method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116462173A true CN116462173A (en) | 2023-07-21 |
Family
ID=87173939
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310641290.7A Pending CN116462173A (en) | 2023-06-01 | 2023-06-01 | Method for preparing ferric phosphate by iron method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116462173A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102464309A (en) * | 2010-11-19 | 2012-05-23 | 河南环宇集团有限公司 | Novel method for preparing lithium iron phosphate complex salt positive electrode materials from scrap iron, phosphoric acid and lithium hydroxide |
| CN104817059A (en) * | 2015-04-29 | 2015-08-05 | 江西东华科技园有限责任公司 | Method for preparing battery-grade iron phosphate from reaction between iron powder and phosphoric acid |
| CN114436233A (en) * | 2022-02-22 | 2022-05-06 | 四川大学 | Preparation method of iron phosphate |
| CN115353084A (en) * | 2022-07-06 | 2022-11-18 | 宜宾天原锂电新材有限公司 | Method for producing lithium iron phosphate by using ferric phosphate dihydrate as raw material through one-step method |
-
2023
- 2023-06-01 CN CN202310641290.7A patent/CN116462173A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102464309A (en) * | 2010-11-19 | 2012-05-23 | 河南环宇集团有限公司 | Novel method for preparing lithium iron phosphate complex salt positive electrode materials from scrap iron, phosphoric acid and lithium hydroxide |
| CN104817059A (en) * | 2015-04-29 | 2015-08-05 | 江西东华科技园有限责任公司 | Method for preparing battery-grade iron phosphate from reaction between iron powder and phosphoric acid |
| CN114436233A (en) * | 2022-02-22 | 2022-05-06 | 四川大学 | Preparation method of iron phosphate |
| CN115353084A (en) * | 2022-07-06 | 2022-11-18 | 宜宾天原锂电新材有限公司 | Method for producing lithium iron phosphate by using ferric phosphate dihydrate as raw material through one-step method |
Non-Patent Citations (1)
| Title |
|---|
| JU GUO等: "A novel environment-friendly synthesis of high purity micron iron phosphate and its application as a precursor of lithium iron phosphate", MATERIALS RESEARCH EXPRESS, 4 September 2020 (2020-09-04), pages 1 - 14 * |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108609595B (en) | Iron phosphate and preparation method and application thereof | |
| CN113912032B (en) | Method for recycling and preparing battery-grade lithium carbonate and ferric phosphate from waste lithium iron phosphate battery positive electrode powder | |
| CN108110357A (en) | A kind of method that valuable metal is recycled from positive material of waste lithium iron phosphate | |
| EP4269337A1 (en) | Method for recovering lithium in lithium iron phosphate waste and application thereof | |
| CN110643814B (en) | Method for removing aluminum and recycling waste lithium iron phosphate batteries | |
| CN109368612A (en) | Method for preparing battery-grade iron phosphate by using iron phosphate production wastewater and iron phosphate prepared by method | |
| CN114436233A (en) | Preparation method of iron phosphate | |
| CN109706328B (en) | Method for preparing ternary feed liquid by back-extracting nickel-cobalt-manganese-loaded organic phase with metal nickel acid dissolving solution | |
| CN113845100A (en) | Iron phosphate and preparation method and application thereof | |
| CN112174106A (en) | Battery-grade iron phosphate and preparation method thereof | |
| CN114560455A (en) | Method for preparing battery-grade iron phosphate by using ferrous sulfate and phosphoric acid | |
| GB2620048A (en) | Preparation method for sodium ferrovanadium phosphate material and application thereof | |
| CN111137869A (en) | Preparation method of lithium iron phosphate | |
| CN109928375B (en) | Method for preparing iron phosphate by using monocalcium phosphate | |
| CN113968578B (en) | Method for synthesizing ferric phosphate by using titanium dioxide byproduct ferrous sulfate | |
| CN113023700A (en) | Preparation method of high-purity nanoscale iron phosphate | |
| CN116259811B (en) | Method for preparing vanadium electrolyte from sodium vanadate solution | |
| CN116462173A (en) | Method for preparing ferric phosphate by iron method | |
| CN112813273A (en) | Method for recycling cobalt, nickel and manganese in ternary battery positive electrode waste | |
| CN114572954B (en) | Method for preparing battery grade ferric phosphate by using pyrite cinder | |
| CN114751390B (en) | Multi-ion doped battery-level ferric phosphate material and preparation method thereof | |
| CN114084878B (en) | Preparation method for synthesizing ferric phosphate by using double iron sources | |
| CN116534824B (en) | Method for preparing ferric phosphate by continuous oxidation process | |
| CN115072688A (en) | Method for recycling all components of waste lithium iron phosphate battery | |
| CN101546825A (en) | Manufacture method of anode material of lithium ion battery |
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 |