A kind of preparation method of battery grade lithium carbonate

Abstract

The invention discloses a preparation method of battery-grade lithium carbonate. The preparation method comprises the following steps: taking a lithium adsorption and desorption eluent as a raw material, performing primary and secondary monovalent ion selective electrodialysis treatment, concentrating and enriching a lithium ion by utilizing the monovalent ion selectivity of a monovalent ion selective cation membrane and a monovalent ion selective anion membrane, and intercepting magnesium ions, sulfate ions and borate ions, thereby realizing efficient separation of lithium and magnesium as well as sulfate and borate ions and other impurity ions and lithium concentration and obtaining a lithium-rich concentrated solution with a lithium content of 10-20 g / L and a ratio of magnesium to lithium of 0.1-1; obtaining the battery-grade lithium carbonate through the steps of deep calcium and magnesium removal, heavy lithium conversion, filtering and washing, drying, cooling and the like. According to the preparation method disclosed by the invention, the preparation process of the battery-grade lithium carbonate is greatly shortened, the process continuity is obviously improved, the cost is reduced, and the bottleneck problem of magnesium removal and concentration by using the salt lake lithium adsorption and desorption eluent with high magnesium-lithium ratio is solved.

Description

technical field

[0001] The invention belongs to the technical field of material preparation, and in particular relates to a method for preparing battery-grade lithium carbonate. Background technique

[0002] Using salt lake, geothermal, oilfield water, seawater and other high-magnesium-lithium ratio and low-grade liquid lithium ores as raw materials, lithium is extracted by adsorption method, and the concentration of lithium chloride in the obtained lithium-rich eluent is generally lower than 1000mg / L, and entrained There are more magnesium salts and a small amount of impurities such as sulfate and borate, and the ratio of magnesium to lithium is higher than 1, even reaching more than 10. It must be further removed from magnesium and enriched before it can be used for lithium carbonate, lithium chloride, etc. Preparation of basic lithium salts. The existing treatment technology generally adopts precipitation method, cation exchange method or nanofiltration method to remove ...

Examples

preparation example Construction

[0042] like figure 1 Shown, the invention provides a kind of preparation method of battery grade lithium carbonate, comprises the steps:

[0043] Step 1: Obtaining and preprocessing raw materials.

[0044] The lithium-containing feed liquid used in the present invention is derived from the eluent of adsorption and extraction of lithium, wherein the weight ratio of magnesium to lithium ions is 0.3-20, and the lithium content is 80 mg / L-10000 mg / L. Preferably, the weight ratio of magnesium and lithium ions in the lithium-containing feed solution is controlled to be 0.5-10; the lithium ion content is 100 mg / L-7000 mg / L, which is more effective.

[0045] The solid impurities in the lithium-containing feed solution are removed, so that the suspended solids (SS) content after filtration is not higher than 5 mg / L.

[0046] After the lithium-containing feed solution is pretreated, the pH value is adjusted to 2-8 to obtain the first desalination stock solution. The first desalted st...

Embodiment 7

[0091] This embodiment is the process of using the lithium-rich concentrated solution obtained in embodiment 5 or embodiment 6 as a raw material to prepare battery-grade lithium carbonate.

[0092] Add 2.5kg of caustic soda per ton of sodium carbonate, prepare a sufficient amount of 28% soda ash with deionized water under the condition of heating and stirring, and vacuum filter it for later use. At the same time, prepare a sufficient amount of 30% caustic soda solution with deionized water for subsequent use.

[0093] Take 5L of the lithium-rich concentrated solution obtained in Example 6, heat it to 60°C, and add 40mL of the pure lye at a ratio of 7L to 9L per cubic meter under sufficient stirring conditions, and then slowly add 30% caustic soda solution to form the first reaction solution until the pH of the first reaction solution reaches 13.0, and a total of 139 mL of 30% caustic soda solution is consumed.

[0094] After continuing to stir and react for 40min, filter to o...

technical field

[0001] The invention belongs to the technical field of material preparation, and in particular relates to a method for preparing battery-grade lithium carbonate. Background technique

[0002] Using salt lake, geothermal, oilfield water, seawater and other high-magnesium-lithium ratio and low-grade liquid lithium ores as raw materials, lithium is extracted by adsorption method, and the concentration of lithium chloride in the obtained lithium-rich eluent is generally lower than 1000mg / L, and entrained There are more magnesium salts and a small amount of impurities such as sulfate and borate, and the ratio of magnesium to lithium is higher than 1, even reaching more than 10. It must be further removed from magnesium and enriched before it can be used for lithium carbonate, lithium chloride, etc. Preparation of basic lithium salts. The existing treatment technology generally adopts precipitation method, cation exchange method or nanofiltration method to remove ...

Examples

preparation example Construction

[0042] like figure 1 Shown, the invention provides a kind of preparation method of battery grade lithium carbonate, comprises the steps:

[0043] Step 1: Obtaining and preprocessing raw materials.

[0044] The lithium-containing feed liquid used in the present invention is derived from the eluent of adsorption and extraction of lithium, wherein the weight ratio of magnesium to lithium ions is 0.3-20, and the lithium content is 80 mg / L-10000 mg / L. Preferably, the weight ratio of magnesium and lithium ions in the lithium-containing feed solution is controlled to be 0.5-10; the lithium ion content is 100 mg / L-7000 mg / L, which is more effective.

[0045] The solid impurities in the lithium-containing feed solution are removed, so that the suspended solids (SS) content after filtration is not higher than 5 mg / L.

[0046] After the lithium-containing feed solution is pretreated, the pH value is adjusted to 2-8 to obtain the first desalination stock solution. The first desalted st...

Embodiment 7

[0091] This embodiment is the process of using the lithium-rich concentrated solution obtained in embodiment 5 or embodiment 6 as a raw material to prepare battery-grade lithium carbonate.

[0092] Add 2.5kg of caustic soda per ton of sodium carbonate, prepare a sufficient amount of 28% soda ash with deionized water under the condition of heating and stirring, and vacuum filter it for later use. At the same time, prepare a sufficient amount of 30% caustic soda solution with deionized water for subsequent use.

[0093] Take 5L of the lithium-rich concentrated solution obtained in Example 6, heat it to 60°C, and add 40mL of the pure lye at a ratio of 7L to 9L per cubic meter under sufficient stirring conditions, and then slowly add 30% caustic soda solution to form the first reaction solution until the pH of the first reaction solution reaches 13.0, and a total of 139 mL of 30% caustic soda solution is consumed.

[0094] After continuing to stir and react for 40min, filter to o...

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