Process for the recovery of metals

A process for the extraction of a metal selected from the group consisting of tungsten, molybdenum, chromium and vanadium metal values from an aqueous solution containing an oxyanion of at lest one of said metals, the absence of halogen or pseudohalogen anions, and an acid concentration of 1 to 30 grams per liter sulphuric acid, which comprises contacting the aqueous solution with a solution in a water-miscible organic solvent of an imidazole selected from the group consisting of 1-isodecylbenzimidazole, 1-(2-hexyldecyl)benzimidazole, 5-methyl-1-(2-hexyldecyl)benzimidazole, 6-methyl-1-(2-hexyldecyl)benzimidazole, 1-decyl-2-alkylbenzimidazole where the 2-alkyl is a mixture of C.sub.7, C.sub.8 and C.sub.9 alkyl groups, 1-(2'-hexyldecyl)2-ethyl-4,5,6,7-tetrahydrobenzimidazole and 1-(2'-hexyldecyl)4,5,6,7-tetrahydrobenzimidazole so as to provide an aqueous phase and an organic phase and separating the aqueous phase from the organic phase which contains in solution a complex of the metal oxyanion and the imidazole.