China Nonferrous Metallurgy

Adjusting the viscosity of copper slag is a key factor to improve the depletion effect of copper slag and promote the separation of slag-copper. In this paper, the viscosity of copper slag is measured by a high-temperature viscometer, and the effects of additives CaO, Al₂O₃ and Cu₂O on the viscosity of copper slag at different temperatures are studied. The research has reached the following conclusions. Under the same temperature conditions, the viscosity of the copper slag first decreases and then increases with the increase of the CaO content; when the CaO content increases to 6%, the viscosity of the copper slag decreases to the minimum; when the CaO content reaches 7%, the CaO and the slag the substance generates refractory compounds, which causes the viscosity of the slag to increase. In the process of slag depletion, Al₂O₃ is considered to be an acidic substance; the addition of Al₂O₃ can form high melting point compounds and increase the liquid phase temperature of the copper slag, resulting in an increase in the viscosity of the copper slag. In the process of slag depletion, Cu₂O reacts with Fe²⁺ ions in the slag to form Fe₃O₄, which increases the viscosity of the copper slag. With the increase of the content of additives Al₂O₃ and Cu₂O, the phase composition of the copper slag is changed, and the viscosity rheological apparent activation energy of the copper slag is increased.