Method for extracting lithium salt from aluminum electrolyte by utilizing fluoride roasting and acid leaching

The invention discloses a method for extracting lithium salt from aluminum electrolyte by utilizing fluoride roasting and acid leaching, and belongs to the technical field of inorganic chemistry. The method comprises the following steps: step 1: mixing materials; and step 2: carrying out fluoride roasting; and step (3): (1) carrying out acid leaching and filtering to obtain primary filtrate and primary filtered substances; (2) respectively treating the primary filtrate and the primary filtered substances to obtain secondary filtrate and secondary filtered substances; (3) respectively treating the secondary filtrate and the secondary filtered substances to obtain tertiary filtrate and tertiary filtered substances; and (4) respectively treating the tertiary filtrate and the tertiary filtered substances. According to the method disclosed by the invention, an element lithium in the electrolyte can be effectively extracted, so that energy consumption for electrolytic aluminum production is reduced; lithium carbonate chemical raw materials with a high additional value are recycled, and the used raw materials are common raw materials in the chemical field, so that the comprehensive average extraction cost is relatively low; various substances can be separated out, and the obtained substances are relatively high in purity; and the lithium element influence problem is solved for the aluminum electrolysis industry, benefits are increased, and the comprehensive level of the aluminum electrolysis industry in China is improved.