Preparation method of industrial grade lithium chloride

Abstract

A method for preparing industrial-grade lithium chloride, comprising the following steps: providing a lithium-containing solution; stirring the lithium-containing solution, detecting the contents of sulfate ions and calcium ions in the lithium-containing solution, and obtaining the sulfate ions in the lithium-containing solution and the total number of moles of calcium ions; add barium carbonate powder to the lithium-containing solution and stir and heat, then carry out the first static precipitation operation to obtain the lithium-containing mixed solution; carry out the pH adjustment operation on the lithium-containing mixed solution, and then carry out the second step after stirring. Static precipitation operation for the first time, after filtration, lithium chloride solution and filter residue are obtained; the lithium chloride solution is evaporated, concentrated and dried to obtain industrial grade lithium chloride. The above-mentioned preparation method of industrial grade lithium chloride, removes sulfate radical ion and calcium ion simultaneously by adding barium carbonate, avoids repeatedly adding impurities-removing agent, adjusts pH and removes cations such as iron and magnesium, and redundant barium carbonate can be removed together when filtering, It is easy to control, avoids the introduction of other impurities, and the obtained lithium chloride has high purity, simple process, energy saving and high efficiency.

Description

Preparation method of industrial grade lithium chloride technical field The present invention relates to a kind of lithium production technical field, particularly relate to a kind of technical grade lithium chloride preparation method. Background technique Lithium chloride is widely used in lithium battery industry, and the overall production process of lithium chloride can be divided into following steps: solution Preparation, purification, removal of impurities, concentration, dry packaging, due to the wide source of basic raw materials required for lithium chloride, the impurities contained in lithium chloride There are many types of items, but the main difficulty in removing impurities in the production process is concentrated on the two impurities items of sulfate radical and calcium ion. At present, Impurity removal methods include precipitation method, membrane method, resin exchange method, etc. Among them, the membrane method has a short process flow and simp...

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Problems solved by technology

[0002] Lithium chloride is widely used in the lithium battery industry. The production process of lithium chloride can be divided into the following steps: solution preparation, purification and impurity removal, concentration, and dry packaging. There are many types of impurities contained in lithium, but the main difficulty in removing impurities in the production process is concentrated on the two impurities of sulfate and calcium ions. At present, impurity removal methods include precipitation method, membrane method, resin exchange method, etc. Among them, the membrane method has a short process flow and simple equipment, but it has high cost, and there are problems such as easy damage to the membrane during the production process, penetration, and unstable quality. The resin exchange method has the advantages of high efficiency and good removal effect, but the same There are problems such as high cost, resin regeneration and process loss, and the cost of waste resin treatment is high. The precipitation method effectively removes the waste by controlling the appropriate precipitant, pH value, reaction temperature, reaction time, feeding speed, stirring speed and other process parameters. It has been applied industrially, but the control conditions are relatively strict, and it cannot meet the requirements of industrial production well. However, the comprehensive process flow and precipitation method are still the main method for removing impurities in industrial production. The impurity removal process is easy to operate

[0003] However, due to the special needs of the lithium battery industry, the impurity content in lithium chloride has a great impact on product performance. How to reduce the impurity content has always been the focus and difficulty in the production process of lithium chloride

If the production raw materials contain a large amount of impurities such as sulfate, calcium ions and a small amount of iron and magnesium ions, the general practice is to adjust the pH value to about 10 with liquid caustic soda to remove iron and magnesium impurities, then add barium chloride to remove sulfate ions, and then add Sodium carbonate removes calcium ions, and after filtration and separation, it is concentrated and dried for production. The above method has extremely strict requirements on the amount of impurity removal reagents, because liquid caustic soda, barium chloride and sodium carbonate are all soluble substances, of which barium ions and sodium Ions have restrictions on the content of lithium chloride products. Therefore, when the amount of impurity remover added is insufficient, there is no good effect of impurity removal. If the amount added is too large, barium ions and sodium ions will exceed the standard, resulting in chlorine Lithium products are unqualified, so there are certain difficulties in actual control

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