Production method for high-purity ferric phosphate

A production method and high-purity phosphoric acid technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of high impurity content and uneven iron phosphate impurity content, and achieve the effect of overcoming the low purity of the product

Active Publication Date: 2018-04-13
GUIZHOU DALONG HUICHENG NEW MATERIAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the impurity content of iron phosphate in the market is uneven, and the impurity content is relatively high

Method used

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  • Production method for high-purity ferric phosphate
  • Production method for high-purity ferric phosphate
  • Production method for high-purity ferric phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043]Add 1000L of pure water to the reaction kettle, add 300kg of industrial grade ferrous sulfate heptahydrate, raise the temperature to 60°C, add 2.5kg of reduced iron powder, hydrolyze for 3 hours, adjust the pH to 4.5-5.0, and then add 0.5 kg SDD (Sodium Dimethicone), add 2L of 0.05% cationic polyacrylamide after reacting for 1 hour, stir well and filter; add 2L of 55% hydrofluoric acid dropwise in the filtrate, stir and keep warm at 60°C for 2 hours and filter; Add 4 liters of 85% phosphoric acid under stirring, stir and react for 2 hours, let it stand for 2 hours, and filter to obtain a pure ferrous sulfate solution; add 180L of 27.5% hydrogen peroxide to the above ferrous sulfate solution to ensure divalent After the iron has been completely converted into ferric iron, add 2kg PEG to the reactor and stir well, then add dropwise ammonium dihydrogen phosphate solution (150kg ammonium dihydrogen phosphate dissolved in 400L pure water), and add phosphoric acid in an appropr...

Embodiment 2

[0048] Add 1200L of pure water to the reaction kettle, add 450kg of industrial grade ferrous sulfate heptahydrate, raise the temperature to 60°C, add 2.5kg of reduced iron powder, hydrolyze for 3 hours, adjust the pH to 4.5-5.0, and then add 0.5kg After SDD (Sodium Dimethicone) was reacted for 0.5 hours, add 3L of 0.05% flocculant, stir well and filter; add 2L of 55% hydrofluoric acid dropwise in the filtrate, stir and keep warm at 60°C for 2 hours to react and filter; Add 4 liters of 85% phosphoric acid, stir and react for 2 hours and then stand still for 2 hours, filter to obtain pure ferrous sulfate solution; add 300L of 27.5% hydrogen peroxide to the above ferrous sulfate solution to ensure that ferrous iron has all been converted into trivalent iron After valence of iron, add 2.5kgPEG to the reaction kettle and stir well, then add dropwise ammonium dihydrogen phosphate solution (250kg ammonium dihydrogen phosphate dissolved in 600L pure water), add phosphoric acid in an ap...

Embodiment 3

[0052] Add 2 mol / L 1500 liters of iron filings and sulfuric acid to the reaction kettle to form a ferrous sulfate solution, raise the temperature to 60°C, add 3 kg of reduced iron powder, hydrolyze for 3 hours, adjust the pH to 4.5-5.0, and then add 1.5 kg SDD (Sodium Dimethicone), after reacting for 0.5 hours, add 4L of 0.05% flocculant, stir well and filter; add 5L of 55% hydrofluoric acid dropwise in the filtrate, stir and keep warm at 60°C for 2 hours and filter; Add 6 liters of 85% phosphoric acid under stirring, stir for 2 hours and then stand still for 2 hours, filter to obtain a pure ferrous sulfate solution; add 500L of 27.5% hydrogen peroxide to the above ferrous sulfate solution to ensure that the ferrous iron has been completely converted After making ferric iron, add 4kg PEG to the reaction kettle and stir well, then add dropwise ammonium dihydrogen phosphate solution (450kg ammonium dihydrogen phosphate dissolved in 1000L pure water), add phosphoric acid in an app...

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Abstract

The invention relates to a production method for high-purity ferric phosphate. Ferrous sulfate solution dissolved by a raw material, i.e., iron sulfate heptahydrate crystal used for producing ferric phosphate or ferrous sulfate solution generated by the reaction of iron and sulfuric acid is subjected to three-time impurity-removal and purification processing; the purified ferrous sulfate solutioncarries out oxidation reaction with hydrogen peroxide to generate ferric sulfate solution; under the condition of emulsifier, phosphate solution is dripped to react to synthesize ferric phosphate precipitates, or phosphoric acid is added into the purified ferric sulfate solution; after evenly mixing, hydrogen peroxide is added for oxidation, emulsifier is added, and ferric phosphate precipitates are synthesized; then, the ferric phosphate precipitates are aged, rinsed, filtered and dried to prepare aqueous or anhydrous high-purity ferric phosphate. The synthesized high-purity ferric phosphatehas an impurity index that potassium, sodium, calcium, magnesium and manganese are less than 50ppm, titanium and aluminum are less than 20ppm, and heavy metal ions, i.e., cobalt, nickel, zinc, copper,lead, chromium are less than 5ppm. By use of the production method, the problems of low purity and more impurity of a product obtained in the prior art are overcome.

Description

technical field [0001] The invention belongs to the technical field of positive electrode materials for power batteries, and in particular relates to a production method of high-purity iron phosphate. Background technique [0002] Lithium iron phosphate (LiFePO4) is a new generation of lithium-ion battery cathode material, its theoretical specific capacity is 170mAh g-1, the actual specific capacity of the product can exceed 140mAh / g (0.2C, 25 ℃), and the voltage platform is 3.4V (relative to Compared with Li / Li+), it has the advantages of low price and good thermal stability, and does not contain any heavy metal elements harmful to the human body. It is environmentally friendly and safe. It also has excellent cycle performance. Under 100% deep discharge conditions, it can be Charge and discharge more than 2000 times. Therefore, lithium iron phosphate is considered to be an ideal cathode material for lithium-ion batteries. At present, the preparation of lithium iron phosph...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/37
CPCC01B25/375C01P2006/80
Inventor 朱海军彭天剑刘务华申喜元姚金华
Owner GUIZHOU DALONG HUICHENG NEW MATERIAL CO LTD
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