The single-particle laminar-flow technique was used to study flash-oxidation of three different copper concentrates in nitrogen-oxygen atmospheres that ranged from N2 to N2 + 50 vol% O2. Gas preheating temperatures were 500-1100°C and the particle-size fractions studied were: with tetrahedrite 20 - 38 μm and 62 - 74 μm; with chalcopyrite 28 - 38 μm, 38 - 44 μm; 44 - 62 μm and 62 - 74 μm; and with Equity - 38 μm and 62 - 74 μm. The effect of the residence time of the particles on sulphur, antimony, and arsenic removal was studied in the range 0.1-0.35 s. Scanning-electron microscopy combined with energy-dispersive and back-scattered electron analysis was used to determine the morphology and mineralogy of the reacted particles. Total desulphurization of chalcopyrite and tetrahedrite concentrates was achieved under the most oxidizing conditions, while the sulphur removal from the Equity-concentrate was somewhat weaker. The removal of antimony from tetrahedrite and Equity-concentrates was found to reach a maximum with low oxygen concentrations in the reaction gas at high gas preheating temperatures; there was 82 and 85% of the original antimony left in the samples, respectively. The arsenic removal was found to be connected with the antimony removal and about 80 and 99% of the original arsenic was removed from tetrahedrite and Equity-concentrates, respectively.
|Number of pages||51|
|Journal||Acta Polytechnica Scandinavica, Chemical Technology and Metallurgy Series|
|Publication status||Published - 1992|
|MoE publication type||A1 Journal article-refereed|