Method for recycling rare earth from iron thorium slag in bastnaesite acid leaching process

Abstract

The invention discloses a method for recycling rare earth from iron thorium slag in a bastnaesite acid leaching process. The method comprises the following steps that S1, a rare earth chloride solution obtained in the acid leaching process is taken into a reaction vessel, and a hydrogen peroxide solution is added into the rare earth chloride solution under a strong acidic condition; S2, after thereaction is completed, the reaction solution is heated; S3, soluble carbonate is added into the solution, clarified and purified; S4, an organic rare earth extractant is added into a clarified liquidfor extraction separation; and S5, the soluble carbonate is added into an extract liquid and a raffinate, and clarified and purified to obtain a rare earth precipitate. An existing mode of removing impurities such as iron and thorium is changed, methods such as an oxidation reduction method are used for changing the hydrolysis property of the impurities, the iron and thorium slag amount is reduced, the rare earth loss caused by too much iron and thorium slag amount is prevented while the impurities such as the iron and the thorium are removed, the rare earth recycling effect is improved, compared with the rare earth recycling rate of an original process, the recycling rate of rare earth is improved by 1-2%, and the defects in a traditional technology are overcome.

Description

technical field [0001] The invention relates to the technical field of recovery of bastnaesite rare earths, in particular to a method for recovering rare earths from iron thorium slag in the acid leaching process of bastnaesite. Background technique [0002] At present, the general method of Sichuan bastnaesite treatment is oxidative roasting of rare earth concentrate, hydrochloric acid leaching, and finally a rare earth chloride solution. In the rare earth chloride solution, due to the high content of non-rare earth impurities such as iron and thorium, it will affect the separation of rare earths in the next step. Therefore, it is necessary to remove non-rare earth impurities such as iron and thorium. The most common method for removing iron and thorium impurities is to use The hydrolysis of iron and thorium ions is different from the hydrolysis properties of rare earth ions to remove them. However, because the iron content in rare earth concentrates is relatively high, rea...

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Problems solved by technology

In the rare earth chloride solution, due to the high content of non-rare earth impurities such as iron and thorium, it will affect the separation of rare earths in the next step. Therefore, it is necessary to remove non-rare earth impurities such as iron and thorium. The most common method for removing iron and thorium impurities is to use The hydrolysis of iron and thorium ions is different from the hydrolysis properties of rare earth ions to remove them. However, because the iron content in rare earth concentrates is relatively high, reaching between 3-5%, the amount of slag in the hydrolysis process is relatively large, and the amount of entrained rare earth is large, resulting in The loss of rare earth is relatively large, and the recovery effect of rare earth is poor

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