Process for comprehensively recovering liquid alkali roasting resource of mixed rare earth concentrate

Abstract

The invention relates to a decomposition process for comprehensively recovering a liquid alkali roasting resource of mixed rare earth concentrate, comprising the following steps of: mixing and roasting the mixed rare earth concentrate and sodium hydroxide according to a weight ratio, wherein the roasting temperature is 200-600 DEG C, and the roasting time is 0.5-4 h; watering the roasted mineral water to be neutral; preferentially dissolving an alkali cake by using hydrochloric acid to obtain a less cerium chlorinated rare earth solution; reducing and dissolving residues by using hydrochloric acid after the hydrochloric acid is preferentially dissolved to obtain a rich cerium chlorinated rare earth solution; after extracting and recovering phosphorus of the rich cerium chlorinated rare earth solution, neutralizing the rich cerium chlorinated rare earth solution to obtain thorium enrichment content; recovering fluorine and sodium hydroxide in a roasted mineral water solution; and after extracting and separating the less cerium chlorinated rare earth solution, recovering calcium chloride. The mixed rare earth concentrate is processed by using the method disclosed by the invention. The continuous production of liquid alkali roasting mixed rare earth concentrate is realized. Tetravalent cerium and trivalent rare earth are separated preferably. Rare earth, thorium, fluorine, phosphorus, calcium and the like are comprehensively recovered. Waste gas and radioactive waste residues are avoided. Cleaner production and resource comprehensive recovery are realized.

Description

Technical field: [0001] The invention relates to a comprehensive recovery process of mixed rare earth concentrate liquid alkali roasting resources, which belongs to the field of hydrometallurgy. Background technique: [0002] Baotou is endowed with unique rare earth resources, accounting for 81% of the country's rare earth reserves, and Baotou rare earth concentrates account for more than 60% of my country's smelted rare earth concentrates. The process of extracting mixed rare earths from Baotou rare earth concentrate is mainly concentrated sulfuric acid roasting. However, this process has the following environmental protection defects that are difficult to solve: (1) The roasting tail gas is an acidic gas containing a large amount of sulfur and fluorine, which is treated by water spraying and absorption, but the tail gas is difficult to meet the relevant national emission standards. At the same time, because the spray liquid is a mixed acid of sulfuric acid, fluosilicic ac...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that the existing rare earth concentrate liquid alkali decomposition process is discontinuous, and the valuable resources in the minerals are not recovered, and at the same time, the trivalent cerium is oxidized to tetravalent, and the preferential separation of cerium and other rare earths is realized. Comprehensive recovery of valuable elements rare earth, thorium, fluorine, phosphorus, calcium and other resources, providing a comprehensive recovery process for mixed rare earth concentrate liquid alkali roasting resources

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