Clean strengthening reduction of lead and zinc from smelting waste slag by iron oxide

• Iron oxide was used to strengthen reduction and volatilization of zinc and lead oxides.
• The harmlessness of SWS and recycle of metal value were achieved.
• Mechanism of intensification reduction was constructed.
• A clean and manageable process was obtained.

Massive emissions of smelting waste slag (SWS) cause serious harm to environment because of including toxic metal such as zinc and lead. Reduction-volatilization is considered as a effective method to trap toxic metal elements from SWS. A novel and clean process was developed to strengthen reduction and volatilization of lead and zinc by iron oxide reduction. The effects of temperature, C/Fe molar ratio, holding time and basicity on the volatilization of lead and zinc in the iron oxide reduction system was investigated. The intensified reduction mechanism was briefly analyzed based on results. The leaching toxicity was used to characterize the environmental impact of SWS. This environmentally friendly method has promise to treat hazardous hydrometallurgical residues, smelting slag and dust.

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