A laminar-flow furnace was used to study the combustion of four flotation concentrates (chalcopyrite, pyrite, galena, and sphalerite) in air at temperatures up to 1400C. A special- Iv developed two-colour pyrometer was used to measure the temperature of individual chalco- pvrite and pyrite particles as they underwent combustion. Chalcopyrite and pyrite ignited with very high rates of reaction at air tempera- tures above 480 and 600C respectively, forming molten products. Galena and sphalerite required temperatures in excess of 700 and 1200 respect- ively to attain equivalent rates of reaction._x000D_
The high rates of reaction for galena and spha- lerite were caused by vaporization. Temperature measurements for chalcopyrite and pyrite are reported here, together with vaporization measurements for chalcopyrite, galena, and Sphalerito