D. Mendeleev University of Chemical Technology of Russia, Moscow, Russia:

M. V. Papkova, Post-Graduate Student, e-mail: masshka1@gmail.com
A. I. Mikhaylichenko, Professor, Head of a Chair of Technology of Inorganic Materials, e-mail: mikhayli7@gmail.com
T. V. Konkova, Assistant Professor, e-mail: kontat@list.ru
O. Yu. Saykina, Bachelor, e-mail: saykina.ol@gmail.com

Apatite is one of accessible and prospective sources for production of rare earth metals (REM) in Russia. REM content in apatite concentrate makes 0.9–1.0%. This figure is relatively small comparing apatite with rare earth ores themselves, however, taking into account the volumes of apatite processing in production of mineral fertilizers (8–9 mln. tpy), it is clear that apatite is a potentially important REM source. Processing of apatite concentrate meaning only REM production is not profitable. The most rational solution consists of complex processing of raw materials accompanied by REM sorption extraction from extractive phosphoric acid that is manufactured during apatite processing in sulfuric acid. The effect of phosphoric acid concentration on sorption extraction of REM mix from its solutions, using sulfocationite of КУ-2 type, is examined. It was revealed that increase of phosphoric acid concentration leads to lowering of REM distribution coefficients. It is shown that dehydratative extractive phosphoric acid (EPA) is a prospective source for REM fabrication, owing to lower content of phosphorus oxide in comparison to semi-hydratative acid. Sorption extraction of rare earth metals from industrial samples of extractive dehydratative phosphoric acid with different content of phosphorus oxide (non-boiled, partly boiled, boiled) is examined. It was established that extraction of REM mix concentrate only, not extraction of individual metals is expedient, in connection with close values of REM distribution coefficients (starting from praseodymium) and in order to eliminate losses of the most valuable components from КУ-2 – Ln – EPA. It was also established that usage of ammonium nitrate solution with concentration 300 g/l is most expedient for REM desorption from sulfocationite phase of КУ-2 type.

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