A method for extracting antimony from solids containing antimony sulfides is described. An improvement in the method of extracting antimony by oxidation of an aqueous mixture of the solids in an acid or by oxidation of a leaching liquor obtained by leaching the antimony from the solids with an aqueous basic solution comprises conducting the oxidation in the presence of a catalyst comprising a water-soluble copper salt, a quinone, a hydroquinone or mixtures of one or more of these. The catalyst significantly increases the rate of oxidation and the rate of the recovery of the antimony from antimony sulfide bearing solids, particularly natural ores. Where the oxidation is conducted in a basic solution, the antimony is recovered as pentavalent antimony in the form of metal antimonates. Facile reduction of the metal antimonate to antimony trioxide also is described.