A method of recovering and utilizing salt lake lithium extraction mother liquor and producing a by-product basic magnesium carbonate

Abstract

The invention provides a method of recovering and utilizing salt lake lithium extraction mother liquor and producing a by-product basic magnesium carbonate. The method includes: mixing first lithium carbonate mother liquor and second lithium carbonate mother liquor according to a certain ratio, reacting, filtering, washing, and drying to obtain industrial basic magnesium carbonate hydrate; and removing carbonate ion residue in the mother liquor after reaction with industrial hydrochloric acid having a concentration of 31%, mixing the mother liquor after the carbonate ion removal with brine that is a raw material for producing lithium carbonate according to a ratio, and performing natural crystallization and sodium precipitation for 10-20 days. After the natural crystallization and sodium precipitation, the content of Li+ is 5-6 g/L and the content of Na+ is smaller than 2.5 g/L, thus reaching requirements for using in workshops. By the manner, the lithium carbonate lithium extraction mother liquor is prepared into the raw material brine for production of the lithium carbonate. The method is simple in process and low in cost, and effectively increases the comprehensive utilization rate of the lithium resource.

Description

technical field [0001] The invention belongs to the technical field of inorganic chemical industry, and in particular relates to a method for recycling lithium mother liquor extracted from salt lakes. Background technique [0002] As the basic lithium salt of lithium, lithium carbonate is used as an additive and flux in the process of glass manufacturing and ceramic production. In recent years, the demand for lithium salt products has grown steadily at a rate of 6% to 8% per year, especially with the rapid development of building materials, electronics, automobiles, information, energy storage batteries and other industries, lithium carbonate has become the most important lithium compound. The product. [0003] Due to the different raw materials, the production process of lithium carbonate is also different. Generally, it can be divided into the ore method using ore as raw material and the brine method using brine as raw material. Since Qinghai Lithium Industry Co., Ltd. a...

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Problems solved by technology

The processes of the four companies are different. Qinghai Lithium uses the membrane method to separate magnesium and lithium, Lanke Lithium uses the adsorption method to separate magnesium and lithium, and Guoan Lithium uses the calcination method to separate magnesium and lithium. Due to the differences in the three processes , the lithium carbonate tail liquid produced by each enterprise is different, and the three companies have nothing to learn from each other in terms of tail liquid recycling. Compared with our company, the properties are also quite different, so there is not much reference for our company's recovery and utilization of lithium carbonate tail liquid

During the first phase of the 3,000-ton lithium carbonate project, the two mother liquors were discharged in an abandoned salt pan without any recycling

In May 2012, the 7,000-ton project of the second phase of lithium carbonate was put into operation. The two mother liquors were treated as follows. First, the two mother liquors were mixed into a buffer pool, and the mixed mother liquor was introduced into a special salt pan for storing tail liquor. After the two mother liquids are mixed, the tail liquid system becomes very complicated, which increases the difficulty of recycling

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