China Nonferrous Metallurgy

During the sulfuric acid roasting process of copper anode mud with high selenium and tellurium content, the roasted sand was sintered into large blocks, resulting in a low evaporation ratio of selenium. In response to this issue, this study utilized the high content of elemental copper in high copper slag to explore the synergistic sulfuric acid roasting process of copper anode mud and high copper slag, and conducted conditional experiments. The experimental results indicate that it is feasible to use high copper slag synergistic sulfation roasting process to treat copper anode mud, and under the condition of a mass ratio of copper anode slime to high copper slag (measured by dry weight) of 1∶0.1, the mass ratio of sulfuric acid to the mixture of 0.85∶1, the slurry time of 60 minutes, and the four zones of roasting temperature of 300℃, 480℃, 570℃, 610℃, and 120 minutes, respectively. The selenium content in the roasted sand could be reduced to below 0.1%. Industrial tests have shown that the produced roasted sand particles are small and honeycomb shaped internally. The selenium in the copper anode mud is effectively evaporated, and the average selenium content in the roasted sand is reduced from 6.67% to 0.09%, with a removal rate of 98.65%. The crude selenium generated during the sulfation roasting process has a purity greater than 96% and can be used to produce high-purity selenium or directly sold externally; The copper in the generated roasted sand can be separated by ball milling water leaching, gold can be recovered by chlorination, silver can be recovered by ammonia leaching of gold slag, and finally valuable metals can be further recovered by pyrometallurgical melting of silver slag. Compared with the conventional copper anode mud sulfuric acid roasting method, this process achieves deep evaporation of selenium from copper anode mud and effective treatment of high copper slag, which has promotional value.