An experimental investigation was conducted to elucidate the main features of the processes taking place in the shaft of a continuous flash-converting furnace for solid copper mattes. The experiments were conducted in a large laboratory furnace. The test variables included the matte grade, oxygen content in the process gas, particle size of the oxidation reaction of sulfur remaining in the particles, copper-to -iron atomic ratio, particle-size distribution, morphology, and mineralogy of the reacted particles. The experiments showed substantial differences in the oxidation behavior of high-grade (72 pct Cu) and low-grade (58 pct Cu ) matte particles. Low-grade particles reacted evenly throughout the furnace, increased in size, and experienced no substantial fragmentation during oxidation. High-grade matte particles tended to be oxidized unevenly and experienced severe fragmentation leaking to generation of dust. The order or the effects of the test variables on the observed variables was found to be (1) the oxygen-to -matte ratio, (2) the particle size of the feed material, and (3)the oxygen content in the process gas. Microscopic examination revealed that the oxides of copper and iron were the main oxidation products, with little elemental copper present in the reacted particles. Potential implications of the experimental findings on the operation of an industrial flash-converting furnace are discussed.
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