About the production and application of battery-grade lithium carbonate

Introduction Lithium carbonate is the basic raw material of the lithium salt industry. It can not only be used directly, but also can be used as a raw material to prepare various high-value-added lithium salts and their compounds. High-tech applications such as color phosphors, pharmaceuticals and lithium batteries and other electronic materials have high requirements for the quality of lithium carbonate. Industrial grade lithium carbonate (GB/T11075-2003) must be refined to remove impurities such as inorganic salts. Meet the quality index requirements of various special products. According to the quality requirements of battery-grade micro-powder lithium carbonate products, combined with market demand, Jiangsu Marine Chemical Engineering Technology Research Center carried out industrial tests and trial production of industrial-grade lithium carbonate refined battery-grade lithium carbonate, and achieved good results. The products are used in The production of lithium cobalt oxide and other battery materials has been successful. 1 Refining method of lithium carbonate There are two production methods of industrial grade lithium carbonate: one is to use traditional lithium ore, such as spodumene, lepidolite, etc., and the other is to use lithium-containing brine, such as salt lake brine, underground brine, etc. . The products all contain a certain amount of water-soluble impurities and water-insoluble impurities, which cannot meet the quality requirements of battery-grade micro-powdered lithium carbonate and require refining treatment. According to the nature of the raw materials and the types of impurities, different refining methods can be used to remove impurities. Using industrial grade lithium carbonate as raw material to produce high-purity lithium carbonate, there are causticizing method, electrolysis method, hydrogenation decomposition method and so on. The causticizing method is to causticize industrial lithium carbonate with lime, and after impurity removal treatment, it is converted into lithium hydroxide, and then carbonized with carbon dioxide to produce high-purity lithium carbonate; the electrolytic method is to treat industrial lithium carbonate with hydrochloric acid to remove acid-insoluble substances and After impurities such as calcium and magnesium, high-purity lithium hydroxide solution is prepared by electrolysis, and then high-purity lithium carbonate is prepared by carbon dioxide carbonization; the hydrogenation decomposition method converts lithium carbonate into lithium bicarbonate with greater solubility, and most of the impurities (such as Ca2+, Mg2+, etc.) are not hydrogenated, and are removed by filtration in the form of insoluble carbonate, and then the lithium bicarbonate solution is heated to obtain high-purity lithium carbonate. At present, my country's industrial-grade lithium carbonate is mainly imported from Chile and the United States, and most of them are brine products. Based on the nature of the industrial-grade lithium carbonate products supplied in the market and the types of impurities, the center has determined the appropriate process flow and process operating parameters through laboratory conditions, and built a set of 500t/a battery-grade lithium carbonate production. Device. The device can produce high-purity lithium carbonate products of various specifications and particle sizes according to the needs of different users. The production process is shown in Figure 1 and Figure 2. 2 Product quality and application Battery-grade micropowder lithium carbonate is a white powder, with a volume mass of 2.11, a melting point of 618°C, a boiling point of 735°C, slightly soluble in water, insoluble in alcohol, and easily soluble in acid It is mainly used in the battery industry to manufacture electrode materials such as lithium cobalt oxide, lithium nickel oxide, and lithium manganate, and also used as non-aqueous electrolyte in rechargeable lithium batteries. It has good electrochemical performance and its application fields are still expanding. The quality indicators of the battery-grade micro-powder lithium carbonate products produced by this center are shown in Table 1. 3 Conclusion Using industrial-grade lithium carbonate as raw material, through the self-developed refining technology of the center, it is possible to prepare high-quality battery-grade micro-powder lithium carbonate. Practice has proved that the product can be used to produce electrode materials such as lithium cobalt oxide.