Processing of copper smelting slag using sulfuric acid leaching: technological aspects and solutions

The article focuses on the study of the processes intended for copper smelting slag processing, in order to extract such valuable components as copper, zinc, iron and silica. Various options for slag leaching with the use of sulfuric acid as one of the most promising approaches are considered. Preliminary thermodynamic calculations confirmed the high probability of dissolution of metal oxides when interacting with sulfuric acid. High-temperature leaching resulted in higher recovery rates for copper and other valuable metals. The use of sulfuric acid at the concentration of 50 g/dm3 in combination with the optimization of leaching parameters provided the high efficiency of valuable metal extraction—copper up to 76%, zinc up to 94% and iron in the form of oxide up to 92%. Acceleration of pulp filtering was achieved through two-stage re-pulping with hot water. The study results confirm the prospects of hydrometallurgical methods of slag processing. It opens up opportunities for the development of more efficient technologies for processing copper smelting waste, aimed at maximum extraction of useful components at minimal costs. The study was supported the Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan, Grant No. BR21881939.