Abstract: A molybdenum refining method collects molybdenum with high purity and yield by simple means. The molybdenum refining method includes mixing and grinding a molybdenum ore or concentrate containing molybdenum sulfide, an oxidizing agent, and an alkali or alkaline earth metal salt to produce an alkali or alkaline earth metal salt of molybdic acid from molybdenum sulfide.

Abstract: A method for recovering high purity nickel, cobalt, molybdenum and vanadium from a waste catalyst in high yield by convenient means is provided. The method includes a step of heating a waste catalyst containing valuable metals in a non-oxidizing atmosphere, thereby deoiling an adhered oil content by thermal decomposition, a step of co-milling the deoiled waste catalyst and a chloride to form a chloride of nickel and/or cobalt, a step of water-leaching the co-milled waste catalyst to dissolve nickel and/or cobalt in water, a step of oxidizing leaching residue containing molybdenum and/or vanadium after water leaching to form an oxide of molybdenum and/or vanadium; and a step of subjecting the leaching residue containing the oxide of molybdenum and/or vanadium to alkali leaching to dissolve the molybdenum and/or vanadium in an alkali solution.

Abstract: To simultaneously overcome a drawback in that proceeding of a solid phase carbonization reaction requires high temperature and a drawback in that the reaction requires use of expensive materials. A method for producing a carbide of a Group IVA, VA, or VIA transition metal in the periodic table and/or a composite carbide of the transition metal and iron, the method including the step of co-milling a ferroalloy containing a Group IVA, VA, or VIA transition metal in the periodic table and incidental impurities and a carbon material mainly composed of carbon in a vacuum or an atmosphere of an inert gas to effect a solid phase reaction between the ferroalloy and the carbon material.