Process for autogenous oxygen smelting of sulfide materials containing base metals

A smelting process in which a sulfide material containing metal sulfide values and iron sulfide is combusted autogenously with an oxygen-containing gas comprising roasting a portion of the sulfide material to be smelted, blending the thus roasted portion with unroasted sulfide material, and autogenously smelting the resulting blend of roasted and unroasted material with oxygen in a bounded space and in the presence of a flux for iron oxides to produce a molten metal product, a molten silicious slag and a strong sulfur dioxide off-gas, whereby the grade of said molten metal product is higher than it would have been had only said unroasted sulfide material been fed to said autogenous smelting.