Method for separating lithium fluoride from electrolyte acid leaching solutions

Abstract

The invention discloses a method for separating lithium fluoride from electrolyte acid leaching solutions, and relates to the technical field of extraction of lithium elements from aluminum electrolyte. The method comprises the following steps of S1, preparing alkali liquor for standby application; S2, adding the alkali liquor to aluminum electrolyte acid leaching solutions for neutral reaction, monitoring the fused salt acidity and fluoride concentration in the adding process, and stopping adding the alkali liquor when the PH value is larger than 6 and the fluoride concentration is lower than0.08 g / L; S3, filtering the mixed liquor, and washing and drying filter residues to obtain cryolite products; evaporating and crystallizing filter liquor, and stopping evaporating the filter liquor when the fluoride concentration is monitored to be lower than 0.02 g / L; and S4, filtering the solutions after evaporation, and washing and drying filter cakes to obtain lithium fluoride; evaporating, crystallizing, washing and drying the filter liquor to obtain inorganic salt. According to the method disclosed by the invention, the reaction process is controlled by controlling the fluoride concentration and the acidity, so that lithium ions and other ions are separated to obtain the lithium fluoride with high recovery rate; and meanwhile, cryolite and inorganic salt products with high purity are obtained.

Description

technical field

[0001] The invention relates to the technical field of extracting lithium elements from aluminum electrolytes, and relates to a method for separating lithium fluoride from aluminum electrolyte acidic leaching solutions. Background technique

[0002] With the rapid development of my country's electrolytic aluminum industry, the demand for bauxite resources has increased sharply. my country's high-grade bauxite is already facing depletion, and only a large amount of low-grade bauxite is mined and utilized to produce metallurgical-grade alumina. This medium and low-grade bauxite contains a large amount of alkali metal elements, especially the bauxite in the main production areas of bauxite in my country has a high content of lithium salt. A large amount of alumina containing lithium salts is used as a raw material for electrolytic aluminum production, which leads to changes in the electrolyte composition in the aluminum electrolytic cell, and a large amount of ...