This invention relates to a method of recovering non-ferrous metal sulfides from a metal ore which comprises subjecting the metal ore, in the form of an aqueous pulp, to a froth flotation process in the presence of a flotating amount of a flotation collector wherein the collector comprises a compound which corresponds to one of the formulas ##STR1## wherein R.sup.1 is alkyl, aryl or aralkyl group wherein the aryl and aralkyl can be substituted with a halo or alkyl moiety;R.sup.2 is alkyl, aryl or aralkyl group wherein the aryl or aralkyl can be substituted with a halo or alkyl moiety;R.sup.3 is aryl or aralkyl unsubstituted or substituted with a halo or alkyl moiety;R.sup.4 is alkyl, aryl or aralkyl group wherein the aryl or aralkyl can be substituted with a halo or alkyl moiety; with the proviso that at least one of R.sup.1 and R.sup.2 must be aryl or aralkyl unsubstituted or substituted;under conditions such that the metal sulfide values are recovered in the froth.The collectors of this process are useful under alkaline, neutral and acidic conditions. Such collectors give good recoveries of the mineral sulfide values, with a high selectivity toward the non-ferrous metal sulfide values over the ferrous containing minerals.The novel collectors of this invention result in surprisingly high recovery of nonferrous metal values or sulfidized metal oxide values, and a surprisingly high selectivity toward such nonferrous metal values when such metal values are found in the presence of ferrous-containing metal sulfides. These collectors demonstrate good recovery and good kinetics.