Method for recovering rare earth from rare earth fluoride fused salt electrolysis waste with effects of environmental protection and low cost

Abstract

The invention discloses a method for recovering rare earth from rare earth fluoride fused salt electrolysis waste with effects of environmental protection and low cost. Rare earth fluoride fused salt electrolysis waste is taken as a raw material, and is subjected to breaking, grinding, agitation, mixing, calcining alkali conversion, ball milling, washing, optimal solution leaching, extraction separation, depositing, washing and burning to prepare a single or mixed rare earth oxide. The method has the advantages of high recovery rate of rare earth, low requirement on reaction equipment, repeated use of production sewage, low production cost, energy saving, environmental protection, good working environment, good economic benefit and the like.

Description

technical field [0001] The invention relates to a regeneration technology of rare earth resources, in particular to an environment-friendly and low-cost method for recovering rare earths from rare earth fluoride molten salt electrolysis waste, belonging to the technical field of rare earth resources recovery and reuse. Background technique [0002] Rare earth metals are widely used in electronics, petrochemical, metallurgy, machinery, energy, light industry, environmental protection, agriculture and other fields, and their output and sales are increasing rapidly, especially with the industrialization of rare earth hydrogen storage alloys and NdFeB permanent magnet materials In recent years, the demand for rare earth metals has grown rapidly. At present, single rare earth metals such as La, Ce, Pr, and Nd, and alloys such as Pr-Nd, Gd-Fe, and Dy-Fe are all produced by the fluoride system molten salt electrolysis process. During production, many non-rare earth impurities accu...

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Problems solved by technology

[0003] In the past, waste molten salt was either discarded as industrial waste, or mixed with qualified molten salt at the expense of product quality for continued use. In order to ensure product quality and resource recycling, rare earth molten salt electrolysis is currently Waste residue recovery is mainly divided into sulfuric acid roasting or alkali-transfer roasting; alkali-transfer roasting is carried out under negative pressure or high temperature, which requires high equipment requirements, high energy consumption, and low rare earth yield; sulfuric acid roasting process has a high fluorine conversion replacement rate, but its The separation process of rare earth chloride is the longest. At the same time, a large amount of hydrogen fluoride gas and sulfuric acid are heated and decomposed and acidic gas emerges during the production process. It is difficult to collect and treat the waste gas, which has a great impact on the environment.

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