Russian Chemical-Technological University named after D. I. Mendeleev, Moscow, Russia

T. V. Konkova, Associate Professor of the Department of Technology of Inorganic Substances and Electrochemical Processes, e-mail: kontat@list.ru
Ch. N. Kuin, Post-Graduate Student of Department of Technology of Inorganic Substances and Electrochemical Processes
M. V. Papkova, Senior Engineer of Department of Technology of Inorganic Substances and Electrochemical Processes

The development of the technology of complex processing of phosphate ore with the associated extraction of rare-earth metals is currently an urgent task. The extraction of REM from extractive phosphoric acid obtained by sulfuric acid decomposition of apatite according to the dihydrate method is perspective and economically feasible. Comparative study was made of the sorption extraction of REM ions (for example, lanthanum), iron and aluminum from solutions of phosphoric acid with impurity concentration and P₂O₅, characteristic of extractive phosphoric acid. Sorption was studied with the help of sulphocathionites: microporous KU-2-8 of Russian production and macroporous MTC1600 produced by Purolite, depending on the ionic form of the resin (H⁺, NH₄⁺ and Na⁺). It was found that the macroporous cation exchange resin MTC1600 possesses better sorption properties for lanthanum, in comparison with KU-2-8, which is due to the more developed porous structure of the sorbent matrix, the characteristics of which are ten times higher. Sorption on the MTC1600 is independent of the ionic form of the resine, with a lanthanum recovery of 95%, while a maximum sorption of 54.8% is achieved with the ammonium form of the KU-2-8 exchange resin. The series of selectivities of trivalent cations is as follows La³⁺ > Fe³⁺ > Al³⁺, irrespective of the ion exchange form of the resin and its porous structure. The distribution coefficients of lanthanum between MTS 1600 and phosphoric acid differ by almost 100 times in comparison with iron and aluminum ions, which will make it possible to selectively extract the REM from extractive phosphoric acid and in the presence of a suitable desorbing reagent, obtain a rareearth metal concentrate with practically no impurities.

This work was carried out with the support of the Ministry of Education and Science of the Russian Federation, assignment No. 10.3814.2017/ПЧ.

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