Ivanhoe’s Kipushi zinc mine in the DRC officially reopens
The restart marked exactly a century since the mine first went into production.
A study by researchers from China’s Central South University introduces a new method for recovering copper, lead, and zinc from copper smelting slag, addressing both environmental concerns and resource recovery.
The paper, published in Transactions of Nonferrous Metals Society of China, details the new technique which employs a sulfurization-reduction approach.
Using pyrite as a sulfurizing agent, the novel sulfurization-reduction method facilitates the efficient extraction of metals from slag by combining thermodynamic analysis with practical laboratory experiments.
According to the scientists, the technique has allowed them to recover nearly 98% of the copper and zinc content and about 90% of the lead content in slag.
The article points out that only in 2022, China produced over 11,000 kilotons of refined copper, leading to 2.2 to 3 tonnes of slag per tonne of copper produced. This slag contains valuable metals like additional copper (0.5%–6%), lead (0.2%–0.6%), and zinc (1%–5.5%), which are often not recovered, resulting in resource waste and environmental hazards from leaked toxic ions.
“By significantly reducing the harmful residues in the leftover slag, this method contributes to a more sustainable approach to waste management in the metallurgical industry. It suggests a shift towards more eco-friendly practices, emphasizing the importance of both economic viability and environmental responsibility in resource recovery processes,” the researchers said in a media statement.
