Adoption of Hydrogen as a Climate-Neutral Reducing Agent for Recovering Metals from Copper Slag

This study explores a sustainable approach for the recovery of metal values from copper slag using hydrogen (H₂). The high-temperature isothermal reduction experiments were carried out under a controlled H₂-Ar atmosphere and the subsequent molten slag extraction technique was employed. The elemental concentrations in both the metal/matte and the reduced slag were examined using inductively coupled plasma optical emission spectroscopy and electron probe microanalysis. It was found that the submerged H₂ blowing technique has a superior impact to top surface blowing on recovering metals from copper slag due to improved mass and heat transfer in the slag. Approximately 65 pct of copper of the initial 1.19 wt pct can be reduced into copper alloy after reduction by submerged H₂ blowing with the lowest concentration of 0.4 wt pct in slag. More than 90 pct of zinc and lead deported into the gas phase as metals. This research contributes to the ongoing efforts to enhance the sustainability of metallurgical processes and reduce their environmental footprint.