Reducing Treatment of Copper-smelting Slag: Thermodynamic Analysis of Impurities Behavior

A thermodynamic mathematical model was developed to analyze the behavior of lead (Pb), zinc (Zn), and arsenic (As) during the reducing slag cleaning process in the Vanyukov furnace. This study aims to investigate how various factors, such as temperature, oxygen partial pressure, and phase ratios, influence the behavior of these impurities. Through the application of the model, significant findings were observed: arsenic tends to migrate to the bottom phase, while zinc is subject to considerable vaporization under the operating conditions of the Vanyukov furnace. The results underline the need for effective control over impurity distribution during the slag cleaning process, particularly as the quality of processed copper ores declines due to increased impurity content. The model confirms the establishment of thermodynamic equilibrium during the bubbling of slag with reducing agents, which aligns with previous experimental work. High extraction rates of arsenic (approximately 80%) into the bottom phase were noted across different process modes, while the vaporization of zinc was minimal until copper was almost entirely removed from the slag. These insights are critical for optimizing operational regimes in slag cleaning, thus potentially enhancing the quality of the final metal products.