JSC Industrial and Creative Enterprise “Rezonans”, Ekaterinburg, Russia:

F. G. Sitdikov, Chief Executive Officer
L. I. Galkova, Industrial Engineer

Institute of Metallurgy of Ural Branch of RAS, Ekaterinburg, Russia:
K. V. Pikulin, Investigator Apprentice, Post-Graduate Student, e-mail: pikulin.imet@gmail.com
E. N. Selivanov, Head of Laboratory

We developed the original technology for processing of rhenium-bearing molybdenite concentrates and low-grade raw materials and industrial wastes. It involves the use of the furnace of indirect heating for roasting raw materials, potassium carbonate for leaching roasted product and calcium salt for precipitation of CaMoO₄. The technology was implemented in experimentalindustrial scale using the concentrate after flotation of copper-molybdenum ores (38.8% Mo, 0.085% Re and 31.5% S) of Almalyk MMC. Pyro- and hydrometallurgical processes were carried out using a set of non-standard equipment. Oxidizing roasting was carried out in the tubular rotary kiln furnace of indirect heating with molybdenum and rhenium transfer to the oxide. Limiting the temperature to 600 ^оC allowed to avoid MoO₃ sublimation, but transfered Re₂O₇ into the gas phase. Roast gases after dust removal were directed to a filter-tipped coke. Condensation of rhenium oxides from gas on coke filter leads to recovery of rhenium-containing product. Gases containing 5–7% of the sulfur dioxide solution were neutralized with soda to form sodium sulphite, which was used as a chemical reagent. Hydrometallurgical processing of roasting product to produce MoO₃ was carried out using reactor (1 m³). Each reactor was connected to nutsch filter. Leaching of roasted product was carried out with K₂CO₃ solution at the temperature of 85–90 ^оC and the leaching time of 1 h. The resulting solution was neutralized with nitric acid and was treated with calcium nitrate at the temperature of 95 ^оC for the precipitation of calcium molybdate. Extraction of molybdenum from the solution to the commercial product was 98–99%. Calcium molybdate was treated with nitric acid at 90–95 ^оC to form molybdic acid. Then molybdic acid was calcined to produce quality MoO₃.

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