I. V. Tananaev Institute of Chemistry and Technology of Rare Elements and Mineral Raw Materials (Kola Science Center RAS), Apatity, Russia:
V. A. Matveev, Head of Laboratory, e-mail: matveev@chemy.kolasc.net.ru
D. V. Mayorov, Senior Researcher, e-mail: mayorov@chemy.kolasc.net.ru
A. V. Solovev, Senior Researcher

Our paper shows the prospects of rare-earth, zirconium and niobium production based on integrated treatment of eudialyte. The main methods of acid treatment of this mineral were analyzed. The technological survey results of the integrated technology development of sulfuric acid treatment for eudialyte concentrate were provided. The impact of different factors (temperature, concentration and flow rate of sulfuric acid) upon the reaction pulp filtration rate and the humidity of the insoluble residue after acid decomposition was processed. The rinsing process of the insoluble residue was researched and the conditions to separate rare earth elements from zirconium, niobium and other elements on this stage were found. The distribution of the target components between liquid and solid phases was determined. The process is greatly influenced by the content of free H₂SO₄ in the solution. Method for silicon dioxide extraction from the insoluble residue after eudialyte concentrate decomposition was developed. The impact of ascending fluid velocity upon the silicon dioxide yield from the insoluble residue and its content was defined. On the basis of our investigations, the most efficient technological parameters for the main stages were estimated and the process flow diagram was developed.

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