Hydrometallurgical processing of complex copper–lead–zinc ore from the Chehel-Kureh mine

The Chehel-Kureh copper–zinc–lead deposit poses processing challenges due to complex sulphide inter-growths and unwanted lead/zinc in copper concentrate. This study evaluates roasting followed by leaching to recover metals from run-of mine (ROM) ore and bulk flotation concentrate. Key parameters including temperature, time, acid molarity, liquid-to-solid ratio, and oxidant type were optimised. Roasting ROM at 600 °C for 1 h, followed by 2 M H 2 SO 4 leaching, achieved 94.08% Cu and 94.92% Zn dissolution. For flotation concentrate, optimal conditions were 800 °C roasting and 3.5 M H 2 SO 4 leaching, yielding 86.61% Cu and 92.33% Zn recovery. Although ROM showed higher metal extraction, processing the concentrate proved more economically viable because flotation reduced feed mass by ∼88%, lowering acid consumption and energy costs.