Crystal form transformation method of lithium-containing aluminum electrolyte

Abstract

The invention discloses a crystal form transformation method of lithium-containing aluminum electrolyte and relates to the technical field of extraction and recycling of aluminum electrolyte. The crystal form transformation method comprises the following steps: S1, crushing the lithium-containing aluminum electrolyte; S2, mixing an additive with the aluminum electrolyte powder; uniformly mixing toobtain a mixed material, wherein the additive is one or more of alkali metal oxide except lithium, alkali metal oxysalt except the lithium, which can be transformed into alkali metal oxide under a high-temperature roasting condition, and alkali metal halide except the lithium, and the mol ratio of alkali metal fluoride in the aluminum electrolyte, alkali metal fluoride which is directly added into the additive and alkali metal fluoride which can be formed by the additive under the high-temperature roasting condition to aluminum fluoride in the mixed material is greater than 3; S3, roasting the mixed material at high temperature. According to the crystal form transformation method disclosed by the invention, insoluble lithium salt in the aluminum electrolyte can be transformed into solublelithium salt so that the leaching rate of the lithium salt is improved, the purity of the aluminum electrolyte is improved and the production energy consumption of electrolytic aluminum is reduced.

Description

technical field [0001] The invention belongs to the technical field of extraction and recovery of aluminum electrolytes, and relates to a method for changing the crystal form of lithium-containing aluminum electrolytes. Background technique [0002] The rapid development of my country's aluminum industry has led to a large consumption of bauxite resources in my country. High-grade bauxite has been scarce, and a large number of low-grade bauxite has been mined and used. 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 raw material for electrolytic aluminum production. This alumina is added to the electrolyte, and these lithium salts will be enriched in the aluminum electrolytic cell during use, resulting in an increase in the content of lithium salts in the aluminum el...

AI Technical Summary

Problems solved by technology

However, since the aluminum electrolyte contains Na 2 LiAlF 6 , NaLi 2 AlF 6 , K 2 LiAlF 6 , KLi 2 AlF 6 and other insoluble lithium salts, these insoluble lithium salts are difficult to dissolve in the acid solution, therefore, the leaching rate of lithium salts is low, and the lithium element in the aluminum electrolyte cannot be fully extracted and recovered, and the purity of the obtained aluminum electrolyte is low, and the production capacity of electrolytic aluminum consumes a lot