Preparation method of industrial-grade lithium chloride

Abstract

A preparation method of industrial-grade lithium chloride comprises the following steps: providing a lithium-containing solution; stirring the lithium-containing solution, and detecting the content ofsulfate ions and calcium ions in the lithium-containing solution to obtain the total mole number of the sulfate ions and calcium ions in the lithium-containing solution; adding barium carbonate powder into the lithium-containing solution, stirring and heating, and carrying out primary static precipitation operation to obtain a lithium-containing mixed solution; carrying out pH adjustment operation on the lithium-containing mixed solution, stirring, then carrying out secondary static precipitation operation, and filtering to obtain a lithium chloride solution and filter residues; and carryingout evaporative concentrating and drying on the lithium chloride solution to obtain industrial-grade lithium chloride. In the industrial-grade lithium chloride preparation method, barium carbonate isadded to remove sulfate ions and calcium ions at the same time, repeated adding of an impurity removing agent is avoided, pH is adjusted to remove iron, magnesium and other cations, redundant barium carbonate can be removed together during filtering, control is convenient, introduction of other impurities is avoided, obtained lithium chloride is high in purity, and the method is simple in process,capable of saving energy and efficient.

Description

technical field [0001] The invention relates to the technical field of lithium production, in particular to a method for preparing industrial-grade lithium chloride. Background technique [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...

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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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