JSC “Giredmet”, Moscow, Russia:

O. V. Yurasova, Head of Laboratory, e-mail: OVYurasova@giredmet.ru

A. A. Gasanov, Head of Department of Highly Purified Materials, Rare and Rare-Earth Metals, e-mail: AAGasanov@giredmet.ru

S. A. Vasilenko, Production Engineer

LLC “Delfin Akva”, Moscow, Russia:

T. A. Kharlamova, Senior Researcher, e-mail: harlamova_tanya@list.ru

Taken with liquidus extraction, electrochemical oxidation of cerium (III) is widely applied in rare-earth metal separation practice. This article offers the modern designs of equipment for cerium extraction from rare-earth metal concentrate: – new model of diaphragm electrolyzer for cerium (III) oxidation; – centrifugal extractors cascade (in spite of traditional mixer-settler ones) for cerium (IV) extraction from rare-earth metals. Cerium (III) oxidation process was researched on laboratory electrolyzer using standard test solutions. Experiments proved that anolyte heating to 55 ^оС gives positive results. However, the temperature growth above this indicator slows down the cerium oxidation process due to the catholyte temperature growth and increasing of HNO₃ reduction ratio. There was made the research of anodic current density on current output of cerium oxidation process. The process parameters were defined for obtaining of >99% of cerium for oxidation. There were carried out the researches of cerium extraction from oxidized technological solutions and its purification from rare-earth metal impurities using extraction in phase inversion prevention conditions. Preliminary calculations were carried out for modeling of cerium extraction and separation in cascade. Process testings were carried out together with its mode updating. Obtained results were realized on laboratory extraction cascade, consisting of 20 centrifugal extractors. Stable operation of extraction unit was defined after equilibrium reaching. Cerium dioxide with >99.5% purity was obtained.

This work was carried out within the Meeting No. 14.579.21.0049 (26.08.2014) with the Ministry of Education and Science of Russian Federation (unique identifier RFMEFI57914X0049).

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