Hydrochlorination of Copper-Cobalt Alloy for Efficient Separation of Valuable Metals

Global demand for cobalt is proliferating owing to the transition towards a low carbon economy. Recovery of cobalt from copper-cobalt alloy ensures the sustainability of the cobalt resources as it contains significant amounts of cobalt. This paper proposes a method for hydrochlorination roasting of copper-cobalt alloy with HCl gas followed by water leaching. The influences of the main factors (roasting temperature, roasting time, HCl gas flow rate, and leaching time) on the separation efficiency of the process were investigated. During the hydrochlorination roasting process, the dense structure of copper-cobalt alloy was destroyed, the Si, Cu, Fe, and Co volatilization efficiencies of 72.73%, 8.47%, 0.44%, and 0.07% were obtained. In addition, the Co, Fe, Cu, and Si in the copper-cobalt alloy were mostly transformed into CoCl2, FeCl2, Cu, and SiCl4. This is exceptionally conducive to the subsequent selective water leaching of Co and Fe and reduces the difficulty of subsequent purification. It was also confirmed by the leaching experiments. For the leaching process, Co and Fe were selectively extracted from roasted product, and Cu retained in the residue mainly in the form of metallic copper. The water leaching efficiencies of Co, Fe, and Cu in the roasted product were 87.76%, 93.25%, and 4.85% under optimized conditions.