Abstract: This invention provides a process for improved separation of mono/multi-metallic sulphide minerals from significant amounts of iron sulphides, mainly pyrrhotite and/or their finely divided process middlings. The process comprises subjecting such material to a conditioning stage with at least one water-soluble sulphur-containing inorganic compound as a prerequisite step for further conditioning with nitrogen-containing organic chelating agents, preferably polyethylenepolyamines, prior to froth flotation wherein iron mineral, primarily pyrrhotite is depressed, thus allowing selective recovery of mono/multi-metallic minerals containing non-ferrous metal value(s).

Abstract: A process for protreating chromium-beating metal scrap comprises charging the chromium-bearing metal scrap with an iron oxide-bearing slag into a pyrometallurgical furnace, heating and melting the charge, and maintaining the charge molten at a temperature of at least 1550.degree. C. for a predetermined time period to allow an iron oxide/chromium exchange reaction to take place oxidizing and removing chromium to the sing phase while reducing iron to the metal phase to form an alloy product containing Fe along with the Ni and/or Co, and removing the alloy product for further processing for recovery of metal values.