JSC «Uralmekhanobr» (Ekaterinburg, Russia):

Gazaleeva G. I., Deputy General Director for Analytical Work, Doctor of Engineering Sciences, gazaleeva_gi@umbr.ru
Shikhov N. V., Head of Laboratory, Candidate of Engineering Sciences
Vlasov I. А., Researcher
Shigaeva V. N., Junior Researcher

E-mail (common): umbr@umbr.ru

The paper presents the results of the Donskoy Ore Mining and Processing Complex concentrating plant — the TNC Kazchrome JSC branch plant — chromite tailings with Cr₂O₃ mass fraction of 25.28 % retreatment technology development studies. The technology shall provide for production of high-grade chromite concentrate with chrome oxide mass fraction of at least 49 % and tailings with Cr₂O₃ mass fraction within 10 %. The up-to-date methods of analysis were used for starting tailings material studies, including optical and electronic microscopy with microscopes AxioImager and EVA-MA 15 from Karl Zeiss. The studies of valuable minerals liberation degree and chrome oxide recovery dependence on feed material size permitted to predict possible separation of +0.2 mm size fraction at the head of the process and develop initial processing flow sheet consisting of fine screening, hydrocycloning and screw separation operations. On the basis of separation characteristics of these operations, processing results are predicted, and their analysis showed the advisability of including only one screw separation operation into the process. As a result of the first screw separation, concentrate was produced with chrome oxide mass fraction of 48.3 %; fine screening of 0.2 mm size fraction permitted to separate 19.5 % of tailings with Cr₂O₃ mass fraction of 8.7 %. The obtained middling products were subjected to testing with a view to verify possible separation of final concentrate by means of gravity concentration, magnetic separation and flotation methods. A scaled-up laboratory setup was used to verify a possibility of producing saleable chromite concentrate with Cr₂O₃ mass fraction of 49.08 %, with yield of 37.50 % and Cr₂O₃ recovery being 72.80 %. The technology was accepted for design and engineering development.

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