Method for preparing lithium carbonate by using salt lake brine with high magnesium-to-lithium ratio

Abstract

The invention provides a method for preparing industrial lithium carbonate by using salt lake brine with a high magnesium-to-lithium ratio. In the method, a TBP-CON-KS+FeCl3 is used as an extraction system to extract and back-extract impurity-free salt lake brine with a high magnesium-to-lithium ratio, the residual liquid obtained after back-extraction is converted by alkaline liquor for precipitation, the precipitate is washed to form an industrial lithium carbonate product and the lithium carbonate content is more than or equal to 99.0 percent and is in accordance with the requirements of GB/T 11 075-2003 standards. The method has the advantages that: liquid-liquid extraction with an organic solvent is adopted to realize the separation of lithium from magnesium, the lithium carbonate is precipitated by inorganic slats, the lithium carbonate is extracted from the salt lake brine with a high magnesium-to-lithium ratio, the process is simple, the control is easy, the operational reliability is high and the application range is wide; a process of calcination and diluted lithium solution evaporation and concentration is saved, the energy consumption is only 30 to 50 percent of that of the conventional process for producing lithium carbonate by using lithium-containing brine; initial raw material consumption comparison show that the production cost of the method is only about 8 percent of that of the prior art; and the raw material brine can return to a storage pool after the extraction of the lithium carbonate, so no by production disposal problem is involved, environmental pollution is relatively low and lithium yield in the whole process is more than or equal to 70 percent.

Description

technical field [0001] The invention belongs to the technical field of inorganic chemical industry and relates to a method for preparing lithium carbonate, in particular to a method for preparing industrial-grade lithium carbonate by using lithium-containing salt lake brine, which is mainly suitable for preparing industrial-grade lithium carbonate from salt lake brine with a high magnesium-lithium ratio. Background technique [0002] Lithium is one of the important strategic resources, known as industrial flavor, and has important strategic significance in national defense industry and national high-tech development. Lithium mainly exists in nature in two forms of solid minerals and liquid minerals, among which lithium reserves in salt lake brine account for 66% of the world's lithium reserves. In recent years, with the rapid development of the lithium salt industry, salt lake brine lithium resources have gradually replaced lithium ore and become the main raw material for li...

AI Technical Summary

Problems solved by technology

These two methods both involve the evaporation and concentration of dilute lithium solution, which consumes a lot of energy. In addition, the equipment corrosion of the first method is also relatively large. At the same time, a large amount of magnesium oxide and hydrochloric acid are produced by-products, and there are problems in the way out of the by-products.