I. V. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials of the Russian Academy of Sciences, Kola Science Center, Apatity, Russia:

Е. Р. Lokshin, Chief Researcher, e-mail: lokshin@chemy.kolasc.net.ru
I. R. Elizarova, Senior Researcher
M. P. Ryskina, Senior Researcher
O. A. Tareeva, Researcher

Eudialite concentrate was produced in experimental and industrial scale at the Lovozero Mining and Processing Combine. Our paper shows the data on its composition and its isolated monomineral fractions of eudialyte, lamprophyllite and loparite, which are the main concentrators of rare elements in the concentrate. Zirconium content in the loparite of the eudialyte concentrate is very small: zirconium losses during hydrometallurgical processing of eudialyte concentrate are not determined by the content of loparite in the concentrate. In comparison with the loparite in loparite layers, the loparite of the eudialyte concentrate contains more niobium and less rare-earth elements (REE). At the same time, the sum of REE is depleted in yttrium and REE of the yttrium group. During the hydrochemical processing of the eudialyte concentrate, the possible losses of yttrium and lanthanides of the yttrium group due to the difficulty of decomposition of loparite do not exceed 0.015%, while the loss of various REE of the cerium group can reach 5.9-12.5%. In contrast to existing ideas, it is established that the radioactivity of the euddialite concentrate is determined primarily by the presence of uranium and only to a lesser extent thorium. The distribution of natural radionuclides between eudialyte, loparite and accessory minerals of eudialyte concentrate is estimated. A significant part of thorium and the main amount of uranium are included in the easily decomposed mineral minerals, rather than the hardly decomposable loparite. Since the content of radionuclides is relative to REE and zirconium is high, an assessment of the behavior of radionuclides in the processing of eudialyte concentrate is necessary. The obtained data are necessary for an estimation of efficiency of developed hydrochemical methods of processing of eudialyte concentrate.

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