RHENIUM RECOVERY FROM SARCHESHMEH MOLYBDENITE CONCENTRATE

Rhenium, in the form of ammonium perrhenate was recovered from Sarches hmeh molybdenite concentrates by roasting the concentrates with slaked lime. The effect of the roasting parameters, such as roasting tempera ture, roasting materials and gas composition was investigated. The roa sted materials were leached with water in order to separate the water- soluble calcium perrhenate and the water-insoluble compounds, calcium molybdate and calcium sulfate, that were formed during roasting. Impur e rhenium-bearing solution was passed through a column of strong anion ic quaternary resin (Dow IRA 410) for selective absorption of rhenium ions from the solution. Stripping of the column was carried out with h ypochloric acid. The resultant perrhenic acid solution was exposed to hydrogen sulfide gas in order to precipitate rhenium heptasulfide. To produce ammonium perrhenate, the sulfide was decomposed by ammonia in the presence of hydrogen peroxide. The solution was evaporated and amm onium perrhenate crystals were formed. (C) 1998 Elsevier Science S.A.