Recovery method of rare earth metal electrolysis fused salt slag

Abstract

The invention discloses a recovery method of rare earth metal electrolysis fused salt slag. According to the method, waste fused salt slag generated in the rare earth fused salt electrolysis process of a fluoride system is adopted as raw materials, rare earth fluoride is obtained through raw material classification, crushing, mixed acid dissolution leaching, washing, filter pressing and filter residue firing, rare earth oxide is obtained after filter liquor is subjected to extraction separation, oxalic acid precipitation and firing, and waste liquid generated after filter liquor extraction is subjected to fluorination precipitation and drying to obtain a lithium fluoride solid. According to the method, operation is easy, cost is low, and environment friendliness and energy saving are achieved; no sodium hydroxide or concentrated sulfuric acid is adopted, a hydrochloric acid / nitric acid mixed system is adopted, no hydrogen fluoride or sulfur dioxide gas polluting the environment is generated, and the environment pollution hazard is relieved; and two kinds of rare earth products of rare earth fluoride and rare earth oxide and the lithium fluoride solid wide in application range are obtained at the same time, and the aim of comprehensive recovery and utilization of secondary resources is achieved.

Description

technical field [0001] The invention relates to the field of resource recovery, in particular to a recovery method for rare earth metal electrolysis molten salt slag. Background technique [0002] Rare earths can be widely used in the production of fluorescent materials, rare earth metal hydride battery materials, electric light source materials, permanent magnet materials, hydrogen storage materials, catalytic materials, precision ceramic materials, laser materials, superconducting materials, magnetostrictive materials, magnetic refrigeration materials, magneto-optical storage materials, optical fiber materials, etc. At present, the main methods of rare earth metal smelting are metallothermic reduction and molten salt electrolysis. Common rare earth metals such as La, Ce, Pr, Nd, Gd, Ho and rare earth alloys such as Pr-Nd, Nd-Fe, Dy-Fe are all produced by fluoride system molten salt electrolysis process. [0003] The rare earth molten salt slag produced by the molten salt...

AI Technical Summary

Problems solved by technology

At present, the traditional concentrated sulfuric acid roasting method and sodium hydroxide method are used in the treatment process of rare earth molten salt slag. This process not only consumes high energy and costs, but also produces waste gas containing hydrogen fluoride and sulfur dioxide, which has a certain impact on the environment. , and the purification and treatment measures of waste gas are complicated, and it is difficult to meet the environmental protection requirements

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