Extraction and separation of copper and iron from copper smelting slag: A review

China's copper resources are characterized by low grade and complex composition. A large amount of copper smelting slag (CSS) containing valuable elements such as copper and iron is produced through smelting. With the increasing shortage of copper resources, the full recovery of valuable elements in CSS plays an important part in resource utilization improvement, strengthen environmental protection and promote China's circular economy. In this study, a variety of methods for extracting and separating copper and iron from CSS are reported. The extraction and separation technologies include physical methods (flotation, magnetic separation) and chemical methods (hydrometallurgical and pyrometallurgical). This paper reviews the different technical principles, parameter optimization and mechanism characteristics of extracting and separating copper and iron from CSS. This review provides guidance for the selection and development of secondary resources of CSS or other solid wastes containing iron and copper. And on that basis, a new route to treat CSS by microwave fluidization roasting is put forward in the paper.