CONVERSION OF NON-FERROUS MATTE

A non-ferrous matte conversion process is disclosed in which molten non-ferrous matte, essentially nickel and/or copper sulfide and iron sulfide, is provided in a suitable vessel, such as a modified Pierce-Smith converter. The ba th is stirred from below with a non-reactive sparging gas, such as nitrogen, and surfa ce-blown from above with an oxygen-containing gas. A flux is added to the melt to raise a fluid slag. In addition, cold crushed matte is added to the bath. The co ld matte acts to maintain the temperature of the bath, so as to prevent overheating which can damage the converter lining. The matte addition also serves as a sourc e for additional converter feed. As the reaction progresses, the slag layer is periodically skimmed, and additions of flux and cold matte are made when necessary. When it is no longer possible to raise a slag, a non-ferrous sulfide matte is obtained having a greatly reduced iron content.