Advances in recovery of valuable metals and waste heat from copper slag

Copper slag, which is produced during the smelting of Cu, contains compounds such as oxides of Fe, Cu, Co, Al, Si, Ni, Cr, and Ca. Cu slag contains more valuable metals, such as Cu and Fe, than those in certain raw ores. The recovery and treatment methods for copper slag are presented in this paper. Considerable attention has been paid to metal recovery over the last few decades. However, this consumes large amounts of energy and its low recovery ratio hinders the development of recovery technologies. Consequently, these technologies are economically impractical and difficult to apply on an industrial scale. The temperature of copper slag derived from furnaces is >1300 °C, indicating the potential for recovering a large amount of potential energy. Combined waste heat and metal recovery can be adopted to address the aforementioned issues. However, most fundamental studies on recovery have not included an economic analysis of their technologies. It is worth noting that copper slag can be used as an Fe-adjusting material in cement clinker production owing to its high Fe content. However, metal extraction and waste heat recovery should be performed simultaneously prior to the utilization of Cu slag as a material resource. Copper slag's valuable metal, waste heat and material resource can be recovered comprehensively. Over the last decades, people paid too much attention on metal recovery, however they consumed large amount of energy. Moreover, the low recovery ratio hinders the recovery technology development. Besides, most of these works do not conduct an economic analysis of their technologies. A combination of waste heat and metal recovery may solve this dilemma. It is worth noting that copper slag can be used as an Fe-adjusting material in cement clinker production owing to its high Fe content. Metal extraction and waste heat recovery should be considered before utilization as a material resource. • Recovery method and mechanism of Fe or Cu in copper slag and treatment technology applied to the cement industry have been studied comprehensively. • Waste heat and valuable metals should be recovered simultaneously. • A critical grade of metal extraction should be established to prevent sluggish industrialization of these technologies.