FOERFARANDE FOER ANRIKNING AV ICKEJAERNMETALLER VILKA INGAOR I JAERNHALTIGA SULFIDMINERALIER

1389145 Recovery of metals from sulphidic materials INTERNATIONAL NICKEL CO OF CANADA Ltd 23 Oct 1973 [27 Oct 1972] 49278/73 Heading C7D Non-ferrous metals, as alloys with iron, are obtained from ferruginous sulphidic minerals containing the non-ferrous values by heating mineral particles at 800 to 1000‹C for sufficient time to cause a major amount of the non-ferrous metal to diffuse into metallic iron present or formed in situ, cooling, and separating a metallic fraction from the non-metallic fraction. Preferably the mineral, e.g. a pyrrhotite concentrate, is mixed with iron oxide and a reducing agent, e.g. coal, coke or charcoal; agglomerated into a briquette or pellet; heated in a non-oxidizing- atmosphere, at 850-925‹C for up to 30 minutes, which causes nickel to diffuse into the metallic iron formed in situ; cooled, crushed and magnetically separated to yield a metallic fraction containing the majority of the nickel, and less sulphur than in the mineral. In alternative embodiments, the mixture of iron oxide and reducing agent can be replaced by particulate metallic iron; or the iron oxide may be supplied by a calcine which may be the mineral starting material roasted to a low sulphur content; or the iron oxide may be replaced by an oxide of alkali metal or alkaline earth metal, the metallic iron being produced in situ from the mineral.