Patent ID: 6248301
Filing Date: 2001-06-19
Classification: C22B

Abstract:
A process for roasting refractory precious metal ores in the presence of fuels in an oxidizing atmosphere in a fluidized zone comprising: (1) combining said metal ores and said fuels, said fuels being different from said precious metal ores and selected from the group consisting of sulfur, pyrite and mixtures thereof, (2) igniting said fuels in said fluidized zone, (3) supplying oxygen-containing gases to said fluidized zone, and (4) roasting said ores at temperatures from about 400 to about 650.degree. C. in said fluidized zone, wherein the O.sub.2 content of the gases fed to the fluidized zone is from about 20 to 50% by volume and where said roasting provides an exhaust gas having a hydrocarbon content less than about 200 volume parts per million.