An ionic rare earth concentrate acid leaching process

Abstract

The present invention discloses an ionic type rare-earth fine ore acid leaching process which comprises the following steps: first acid leaching of ionic type rare-earth fine ore is performed, the pH value of the reaction system is controlled in 2-3, and a first slag and a first leaching solution are obtained by solid-liquid separation; second acid leaching of the first slag is performed, the pH value of the reaction system is controlled to be less than or equal to 1, a second slag and a second leaching solution are obtained by solid-liquid separation; the second leaching solution is returned to be used in the first acid leaching, the first leaching solution is neutralized and decontaminated, sulfate radicals, iron, aluminum, radioactive substances and heavy metals and other impurities are removed step by step, and a neutralization slag and a rare earth solution are obtained by solid-liquid separation; the rare earth content of the second slag processed by the acid leaching process is less than 5%, the slag amount is less than 7% of the ionic type rare-earth oxide fine ore input amount, the rare earth leaching yield is more than 99%, the radioactive total specific activity of the second slag is less than 7.4 * 104Bq / kg, the second slag belongs to the low radioactive slag, and the memory difficulty is reduced.

Description

technical field [0001] The invention belongs to the field of chemical metallurgy, and in particular relates to an ion-type rare earth concentrate acid leaching process, which can increase the yield of rare earth, recycle associated elements and reduce the generation of radioactive solid waste. Background technique [0002] The purpose of ionic rare earth concentrate acid leaching is to convert solid rare earth concentrate into rare earth solution and remove part of SO 4 2- , Fe 3+ 、Al 3+ , radioactive elements, heavy metals and acid-insoluble impurities, and provide qualified feed liquid for the separation and purification process. At present, the industrial treatment of ionic rare earth concentrates basically adopts the hydrochloric acid leaching process. [0003] At present, the hydrochloric acid leaching process only considers the recovery of rare earth elements. Excessive hydrochloric acid is directly added for leaching to obtain a leaching solution, which is then neu...

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Problems solved by technology

[0009] The above-mentioned methods all recover rare earths from the acid-dissolved slag produced by ion-type rare earth mines, the recovery cost is high, and the recovery of radioactive elements is not considered, and the problem of a large amount of radioactive waste stockpiling has not been solved

[0010] In short, the purpose of the existing ionic rare earth concentrate leaching process or the treatment method of acid leaching residue is mainly to recover the rare earth, and the problem of radioactive elements exceeding the standard in the acid leaching residue and stacking and disposal has not been considered, resulting in a large amount of For radioactive acid-dissolved slag, the enterprise must build a special radioactive waste slag warehouse for stacking, which occupies a large area and requires high maintenance costs

At the same time, during the acid dissolution process, some radioactive elements enter the leaching solution, causing the specific activity of radioactivity in the extraction wastewater to exceed the standard during the extraction and separation process.

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