Institute of Problems of Integrated Subsoil Development named after Academician N. V. Melnikov of the Russian Academy of Sciences, Moscow, Russia

V. A. Chanturiya, Chief Scientific Officer, Academician RAS, Doctor of Technical Sciences, e-mail: vchan@mail.ru
V. G. Minenko, Leading Researcher, Doctor of Technical Sciences, e-mail: vladi200@mail.ru
M. V. Ryzanceva, Senior Researcher, Candidate of Technical Sciences, e-mail: ryzanceva@mail.ru
A. L. Samusev, Senior Researcher, Candidate of Technical Sciences, e-mail: andrey63vzm@mail.ru

A flow chart for processing eudialyte concentrate has been developed, ensuring the total extraction of zirconium — 89.4%, rare earth elements — 82%. At the same time, the loss of zirconium with leaching cake is 9%, rare earth elements — 16%. Low losses of zirconium (1.6%) and rare earth elements (2%) during the processing of the productive solution of nitric acid leaching are achieved by organizing the washing and processing of silica gel, the sequential extraction of zirconium and rare earth elements from the productive solution by chemical precipitation, reagent regeneration and closing of water circuits. Washing and processing of silica gel into sodium metasilicate with the associated production of zirconium silicate and rare earth elements returned to the leaching process reduce the loss of valuable components by 43%. Regeneration of calcium carbonate with the associated production of ammonium nitrate ensures the processing of liquid salt waste (calcium nitrate solutions) and reduction of rare earth elements losses by 11.3%. The circulation of waste solutions and washing waters increases the concentration of valuable components in the productive solution by 5–6% and reduces the consumption of nitric acid by 12.2%. According to preliminary estimates, the gross profit per 1 ton of processed concentrate will amount to approximately 128 thousand rubles. An alternative sorption option for processing an acid leaching solution of eudialyte concentrate for the extraction of rare earth elements and zirconium has been investigated. The possibility of dividing rare earth elements into light and heavy subgroups using synthetic sorption materials has been experimentally substantiated: in the case of using vinyl pyridine resin VP-3Ap, the extraction of light rare earth elements into resin is 68–93%, while 80–92% of rare earth elements belonging to the heavy group pass into eluate.

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