Treatment method of superior molten slag of monazite

Abstract

The invention relates to a treatment method of superior molten slag of monazite. Specifically, the treatment method is a method for extracting and separating iron, uranium, thorium and mischmetal in the superior molten slag of the monazite in a mixed acid solution of hydrochloric acid and nitric acid, and comprises the following steps : thermally dissolving the superior molten slag using hydrochloric acid; separating iron, uranium-thorium and rare earth; separating iron and uranium; preparing mixed feed liquor of hydrochloric acid and nitric acid for thorium and rare earth; separating thoriumand rare earth; and extracting mischmetal. The treatment method is good in uranium, thorium and rare earth separation effect and high in recovery rate, uranium and thorium products meeting nuclear fuel requirements can be produced, cyclic utilization of acid can be achieved, and the treatment method is environmentally friendly.

Description

technical field [0001] The invention belongs to the field of hydrometallurgy, and specifically relates to a method for extracting and separating iron, uranium, thorium and mixed rare earths in monazite slag in a mixed acid solution of hydrochloric acid and nitric acid. Background technique [0002] my country's industrial-scale processing of monazite and extraction of uranium, thorium and rare earth elements began in the late 1950s. Shanghai Yuelong Chemical Plant dissolved the monazite alkali-dissolved cake with concentrated nitric acid, and then used tributyl phosphate (TBP) in the Separation of uranium, thorium and rare earth in nitric acid solution, because of high consumption, the separation effect is not good. In the early 1970s, it was changed to hydrochloric acid to dissolve rare earth. Separation of uranium, thorium and rare earths. This law has been used until the beginning of this century when the plant was closed due to environmental problems. In addition to diss...

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Problems solved by technology

There are also techniques for extracting uranium with ion exchange resins in sulfuric acid medium, acidic phosphate esters (such as P-204) for extracting thorium, and primary amines for extracting rare earths (such as CN103014359A, CN103014333A, etc.). Two technologies and two extraction agents, the process is complex and difficult to manage, and the separation effect is not ideal, so far there is no report on large-scale production and application

CN104775026 discloses a method for dissolving monazite fine slag with hydrochloric acid, extracting methylphosphonium dimethylheptyl ester from hydrochloric acid solution, and washing impurities with nitric acid to separate uranium, thorium, and rare earth. The uranium and thorium products obtained by the separation have not reached the quality of current practical applications Require

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