Liquid alkali roasting decomposition extraction process of mixed rare earth concentrates

Abstract

The invention relates to a liquid alkali roasting decomposition extraction process of mixed rare earth concentrates, which comprises the following steps of: (1) mixing mixed rare earth concentrates and sodium hydroxide (prepared solution) in the weight ratio of 1:0.5 to 1.5; (2) roasting the rare earth ore mixed with the sodium hydroxide at the roasting temperature of between 150 and 500 DEG C for 0.5 to 4 hours; (3) performing size mixing on roasted ore hot water obtained by roasting, adding oxidant simultaneously for oxidation, and performing washing until the mixture is neutral after the oxidation; (4) dissolving trivalent rare earth preferentially in washed alkali cakes in hydrochloric acid, and controlling the pH value to be between 4 and 5 to prepare rare earth chloride solution with less cerium; and (5) performing reductive dissolution of the hydrochloric acid on cerium dregs dissolved preferentially in the hydrochloric acid, and controlling the pH value to be between 4 and 5 to prepare cerium-rich chloride solution. The mixed rare earth concentrates are processed by adopting the extraction process, so that the continuous production of the alkali-decomposing mixed rare earth ore can be realized, cerium-rich products are extracted preferentially, the treatment capacity of the follow-up extraction separation is relieved, and the pollution-free production and comprehensive utilization of resources are realized.

Description

Technical field: [0001] The invention relates to a process for decomposing and extracting mixed rare earth concentrate liquid by alkali roasting, belonging to the field of rare earth metallurgy 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 aci...

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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 alkali decomposition process requires pickling to remove calcium and cannot be continuously produced. At the same time, the cerium that accounts for 50% of the mixed rare earth ore is preferentially extracted to reduce the processing capacity of subsequent extraction and separation. And realize the recovery of resources such as valuable elements rare earth, thorium, fluorine, etc., provide a kind of mixed rare earth concentrate liquid alkali roasting decomposition extraction process, the invention can make the alkali decomposition process realize continuous industrial production

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