Innovative and green utilization of zinc-bearing dust by hydrogen reduction: Recovery of zinc and lead, and synergetic preparation of Fe/C micro-electrolysis materials

Up to 80 million tons of zinc-bearing dusts are discharged by the steel industry in the word annually, and the traditional pyrometallurgy process of recycling these hazardous wastes with solid carbon as the reducing agent has high energy consumption, large carbon emissions and little added value of products. In this study, we proposed an innovative utilization of zinc-bearing dusts by hydrogen reduction to recover zinc and lead and synergistic prepare iron-carbon micro-electrolysis (ICME) materials for wastewater treatment. The hydrogen reduction behaviors of zinc-bearing dusts pellets were investigated, as well as the properties of the prepared ICME materials (HR) were comprehensively analyzed. The results indicated that the metallization degree, zinc and lead removal degree of zinc-bearing dusts pellets were 98.5 %, 96.8 % and 71.1 %, respectively, under the optimal reduction condition. The synergistic prepared HR with Fe/C of 15:1, specific surface area of 5.158 m2/g and pore volume of 0.01004 cm3/g could remove more than 60 % of COD in wastewater within 2 h. The tight iron-carbon bonding and well-developed pore structure of HR made it equivalent wastewater treatment effects compared to commercial materials. Therefore, the novel process provides a clean and high-value way out for these hazardous wastes.

Automated summary

Up to 80 million tons of zinc-bearing dusts are discharged by the steel industry annually. The traditional pyrometallurgy process for recycling these wastes has high energy consumption and carbon emissions. This study proposes a novel method of hydrogen reduction to recover zinc and lead and produce iron-carbon micro-electrolysis (ICME) materials for wastewater treatment. The results show that under optimal conditions, the zinc and lead removal degree of zinc-bearing dusts pellets reaches 96.8% and 71.1%, respectively, and the prepared ICME materials can efficiently remove COD from wastewater.