Evolution of Size Distribution of Copper

Experiments were conducted to investigate the effects of the initial particle size and oxygen concentration in the process gas on the size distribution of copper concentrate particles oxidized under suspension-smelting conditions. The size distribution was determined by both QEMSCAN® and laser diffraction techniques from samples of reacted particles collected along the reactor length of a laminar-flow reactor. The experimental data indicate that the change in particle size of the particle population was strongly dependent upon the particle size of the feed material, whereas the oxygen concentration in the process gas did not play a significant role in the range of 40-70 vol. %. Particle expansion was the predominant phenomenon in the early stages of oxidation, whereas fragmentation started to occur at further stages of oxidation down the reactor length. The amount of dust, i.e., particles with size smaller than 20 μm, is discussed as a function of the operating conditions tested in the experiments.