Wet-chemical digestion of molybdenum sulphide containing material

Claim 1

A process for the treatment of molybdenum sulfide containing material which comprises: a. agitating together in a first leaching step molybdenum sulfide containing material with an acidic solution containing nitric acid under a temperature of 60°-120° C and pressure conditions which will enable the nitric acid to convert a substantial portion of the molybdenum sulfide to molybdic acid, b. withdrawing reaction products from said first leaching step, said reaction products being free from nitric acid, separating the reaction products of step (a) into a liquid phase and a solid phase, c. the nitric acid content of the acidic solution in step (a) being regulated so that the liquid phase resulting from step (b) is free from nitric acid, d. subjecting the liquid phase resulting from step (b) to solvent extraction with an organic solvent which is capable of dissolving therein most of the molybdenum values contained in the liquid phase resulting from step (b) e. contacting the solid phase resulting from step (b) in a second leaching step with nitric acid having an initial concentration of at least 20% in a quantity which is at least sufficient to completely oxidize all of the molybdenum sulphide in said solid phase, and f. separating the reaction products of step (e) into an acidic solution and solid molybdic acid.