Process for recovering lithium phosphorous from lithium phosphate crude product to prepare battery-level lithium carbonate and iron phosphate

A lithium phosphate, battery-level technology, applied in the direction of lithium carbonate;/acid carbonate, phosphorus compounds, chemical instruments and methods, etc., can solve the problems of high impurities, high acid consumption, low value, etc., to achieve Improve economic value, increase recovery rate, and reduce emissions

Active Publication Date: 2018-02-23
CHENGDU CHEMPHYS CHEM IND
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The traditional process uses a large amount of inorganic acid to dissolve lithium phosphate to form a solution, and then uses a large amount of alkali to neutralize the acid and calcium salt to remove phosphorus to obtain a lithium-containing solution. The traditional process consumes a lot of acid and requires too much alkali to neutralize the acid, The obtained lithium-rich mother liquor has high impurities, and the generated slag has a large amount, high impurities, and low value

Method used

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  • Process for recovering lithium phosphorous from lithium phosphate crude product to prepare battery-level lithium carbonate and iron phosphate
  • Process for recovering lithium phosphorous from lithium phosphate crude product to prepare battery-level lithium carbonate and iron phosphate
  • Process for recovering lithium phosphorous from lithium phosphate crude product to prepare battery-level lithium carbonate and iron phosphate

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preparation example Construction

[0050] In the preparation process of battery-grade ferric orthophosphate in this step C, the reaction temperature is maintained at 80-95° C., and what is obtained at a low reaction temperature is amorphous ferric orthophosphate. The amorphous ferric orthophosphate has a fine particle size and a large specific surface area. Filtering, Difficult to wash, high residue of impurities, increasing the synthesis temperature, the amorphous ferric orthophosphate is transformed into crystalline ferric orthophosphate, which is easy to filter and wash. The chemical reaction equation involved in this step C is as follows:

[0051] Li 3 PO 4 (s)+2H + →LiH 2 PO 4 (l)+2Li +

[0052] LiH 2 PO4(1)→H 2 PO 4 - +Li +

[0053] h 2 PO 4 - →HPO 4 2- +H +

[0054] HPO 4 2- → PO 4 3- +H +

[0055] Fe 3+ +PO 4 3- +2H 2 O→FePO 4 2H 2 O(s)

[0056] D. Preparation of battery grade lithium carbonate

[0057] The lithium-containing mother liquor obtained above is filtered with...

example 1

[0073] This example reclaims lithium phosphorus from crude species to prepare battery-grade lithium carbonate and the specific process of iron phosphate as follows:

[0074] 1. Take 0.5kg of lithium phosphate and add 1.9kg of pure water. After 1 hour of high-speed dispersion and slurry mixing, the sand mill circulates sand for 0.5 hours to obtain lithium phosphate dispersion slurry.

[0075] 2. Take 1.05 kg of ferric sulfate and add water to prepare a solution with an iron content of 55 g / L, stir and dissolve, then filter to obtain a refined ferric sulfate solution.

[0076] 3. Add pure water into the reactor as the bottom liquid, add sulfuric acid to adjust the pH of the solution to 2, stir and heat up to 90°C, then add lithium phosphate slurry and ferric sulfate solution into the reactor simultaneously according to the reaction stoichiometric ratio for reaction. Maintain the reaction temperature at 90°C, control the addition of materials for 2 hours, and keep stirring for 2 ho...

example 2

[0081] This example reclaims lithium phosphorus from crude species to prepare battery-grade lithium carbonate and the specific process of iron phosphate as follows:

[0082] 1. After adding 0.5kg of lithium phosphate to 1.2kg of pure water, high-speed dispersion and slurry mixing for 0.5 hours, sand mill circulation for 1.0 hours to obtain lithium phosphate dispersion slurry.

[0083] 2. Take 1.05 kg of ferric sulfate and add water to prepare a solution with an iron content of 65 g / L. After stirring and dissolving, filter to obtain a refined ferric sulfate solution.

[0084] 3. Add washing water into the reactor as the bottom liquid, add sulfuric acid to adjust the pH of the solution to 2.5, stir and heat up to 85°C, then add lithium phosphate slurry and ferric sulfate solution into the reactor simultaneously according to the reaction stoichiometric ratio for reaction. Maintain the reaction temperature at 85°C, control the addition of materials for 2.5 hours, and keep stirring...

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Abstract

The invention provides a process for recovering lithium phosphorous from a lithium phosphate crude product to prepare battery-level lithium carbonate and iron phosphate, and belongs to the technical field of resource recycling. The process comprises: lithium phosphate slurrying: adding pure water or washing water to the lithium phosphate crude product to prepare slurry, and performing high-speed dispersion and grinding dispersion to obtain uniform lithium phosphate slurry; iron solution preparation: filtering an iron solution to obtain a refined iron solution; iron orthophosphate preparation:adding inorganic acid into a pure water base solution to regulate pH to 2-3, adding the lithium phosphate slurry and the refined iron solution after temperature rise, performing solid-liquid separation after reaction is completed, initially washing a solid by the pure water, re-washing the solid by slurry mixing, and drying and crushing the solid, so as to obtain iron orthophosphate; battery-levellithium carbonate preparation: purifying a lithium-containing mother solution obtained by preparing the iron orthophosphate, and inputting into a mixed solution of sodium carbonate and EDTA to perform lithium deposition reaction, and performing separation, washing, drying and crushing to obtain lithium carbonate. The lithium phosphate crude product is treated by means of the process of the invention, so that iron orthophosphate and lithium carbonate products meeting quality requirements of a lithium battery can be obtained.

Description

technical field [0001] The invention belongs to the technical field of resource recovery and utilization, and specifically relates to a process for preparing battery-grade lithium carbonate and iron phosphate by recovering lithium phosphorus from crude lithium phosphate. Background technique [0002] With the development of the new energy vehicle industry, the application range of lithium-ion power batteries has greatly increased, and the recycling of scrapped power batteries of new energy vehicles is imminent. How to improve the resource utilization of scrap batteries has become a problem of widespread concern in the society. [0003] In recent years, the prices of lithium, cobalt, and nickel products have gradually increased, and the recovery technology of nickel and cobalt is relatively mature. Compared with lithium, the lithium content in power battery materials is low, and conventional acid leaching is used for recovery. The lithium yield of the lithium carbonate produc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/37C01D15/08
Inventor 班文俊蔡荣富李云峰李亚丽
Owner CHENGDU CHEMPHYS CHEM IND
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