Preparation method of special battery-grade ferrous oxalate for lithium iron phosphate

A technology of ferrous oxalate and lithium iron phosphate, which is applied in the preparation of carboxylate, organic chemistry, etc., can solve the problems of large particles of battery-grade ferrous oxalate, high production cost, low purity, etc., to improve the reaction rate and improve the quality. , the effect of reducing production costs

Active Publication Date: 2014-11-05
GANFENG LITHIUM CO LTD
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

2. Use oxalic acid solution and ferrous solution to react to produce battery-grade ferrous oxalate. The disadvantage of the process is that the particles are relatively coarse and must be crushed to obtain a product of 3-5 μm
The above three methods are not complicated in the past, or other organic substances need to be added. The battery-grade ferrous oxalate particles produced are relatively large, the purity is not high, and the production cost is relatively high.

Method used

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  • Preparation method of special battery-grade ferrous oxalate for lithium iron phosphate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] A. Add 175kg of pure water into the impurity removal kettle, start stirring, and add 350kg of ferrous chloride (the liquid-solid weight ratio is 0.5:1), start heating, and after the water temperature rises to 90°C, add reduced iron powder 1.75 kg, control the pH after the reaction=2.5, stir at constant temperature for 3 hours, obtain ferrous chloride solution, and start pressure filtration;

[0031] B. The ferrous salt solution produced in step A is passed through a group of automatic pressure-maintaining and sealed chamber filter presses (the model is XAMY40 / 800-UK), while filtering to remove metallic impurities, non-metallic impurities and excessive reduced iron powder, Obtain pure ferrous salt solution;

[0032] C. When the ferrous chloride filtrate in step B is clear, open the outlet valve of the filter press, close the return valve of the filter press, and quickly inject the ferrous chloride filtrate into the main reaction kettle; when the filter press is completed...

Embodiment 2

[0037] A. Add 700kg of pure water into the impurity removal kettle, start stirring, and add 350kg of ferrous chloride (liquid-solid weight ratio is 2:1), start heating, and after the water temperature rises to 95°C, add reduced iron powder 4.5 kg, control the pH=3 after the reaction, and stir at a constant temperature for 2 hours to obtain ferrous chloride solution;

[0038] B. The ferrous salt solution produced in step A is passed through a group of automatic pressure-maintaining and sealed chamber filter presses (the model is XAMY40 / 800-UK), while filtering to remove metallic impurities, non-metallic impurities and excessive reduced iron powder, Obtain pure ferrous salt solution;

[0039] C. After the ferrous chloride filtrate of the B step is clear, open the filter press outlet valve, close the filter press return valve, and quickly squeeze the ferrous chloride filtrate into the main reactor; Pour 232.68Kg of dihydrate oxalic acid solid (1.05 times the molar number of ferr...

Embodiment 3

[0044] A. Add 1750kg of pure water into the impurity removal kettle, start stirring, and add 350kg of ferrous chloride (the liquid-solid weight ratio is 5:1), start heating, and after the water temperature rises to 97°C, add reduced iron powder 10.5 kg, control the pH=4 after the reaction, and stir at constant temperature for 1 hour to obtain ferrous chloride solution;

[0045] B. The ferrous salt solution produced in step A is passed through a group of automatic pressure-maintaining and sealed chamber filter presses (the model is XAMY40 / 800-UK), while filtering to remove metallic impurities, non-metallic impurities and excessive reduced iron powder, Obtain pure ferrous salt solution;

[0046] C. After the ferrous chloride filtrate of B step is clear, open the outlet valve of the filter press, close the return valve of the filter press, and quickly squeeze the ferrous chloride filtrate into the main reactor; Add 223.8 kg of oxalic acid dihydrate solid (1.01 times the molar nu...

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Abstract

The invention discloses a preparation method of special battery-grade ferrous oxalate for lithium iron phosphate, and the method comprises the following steps of: A) removing impurities, adding pure water, stirring, adding solid ferrite, rising the temperature to 80-100 DEG C, adding reduced ferrous powder, stirring for 1-3 hours at a constant temperature, controlling the pH between 2 and 4, and carrying out filter pressing; B) filtering a ferrite solution, and eliminating ferrous powder and purities; C) adding filtrate into a main reaction kettle after the ferrite solution is clear, adding solid oxalate dehydrate to carry out precipitation reaction at the temperature of 30-60 DEG C after filter pressing, and rising the temperature to the constant temperature of 70-100 DEGC after reaction is performed for 10-60 minutes, wherein the charging time is 5-6 minutes; D) stirring a reaction solution, and carrying out heat preservation for 2-4 hours for aging; E) separating ferrous oxalate by virtue of a centrifugal machine; and F) rinsing and drying separated ferrous oxalate to obtain ferrous oxalate products. The preparation method of the special battery-grade ferrous oxalate for the lithium iron phosphate, which is disclosed by the invention, has the advantages of simple and practical process, low production cost and environmental friendliness, and can be used for further synthetizing the small-granular battery-grade ferrous oxalate in one step, wherein the granularity is less than 5mu m and the purity is larger than 99.55%.

Description

technical field [0001] The invention relates to a preparation method of ferrous oxalate, in particular to a preparation method of battery-grade ferrous oxalate dedicated to lithium iron phosphate. Background technique [0002] Ferrous oxalate molecular formula FeC 2 o 4 2H 2 O, the existing ferrous oxalate production method mainly contains three big classes: 1, make battery grade ferrous oxalate with oxalate solution and ferrous solution reaction, its technological shortcoming is that particle is thicker, just can obtain 3- after must pulverizing 5μm product. If you want to produce 3-5μm products in one step, you need to add additives. 2. Use oxalic acid solution and ferrous solution to react to produce battery-grade ferrous oxalate. The disadvantage of the process is that the particles are relatively coarse and must be pulverized to obtain a product of 3-5 μm. If you want to produce 3-5μm products in one step, you need to add additives. 3. Prepare battery-grade ferrou...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C55/07C07C51/41
Inventor 李良彬白有仙胡耐根马木林刘明李芳芳李鹏俊
Owner GANFENG LITHIUM CO LTD
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