Zero-Waste Recycling Method for Nickel Leaching Residue by Direct Reduction-Magnetic Separation Process and Ceramsite Preparation

摘要

In this paper, a novel process for beneficiation of metallic iron from nickel leaching residue and preparation of ceramsite from tailings by direct reduction-magnetic separation process is reported. The optimal conditions for direct reduction process were 1100 degrees C roasting temperature, 120min duration, and 30wt.% reductant dosage. The reduced sample was benefited from low-intensity magnetic separation. This process yielded an iron concentrate of 82.32wt.% grade and 78.05wt.% recovery. Hence, this metallic iron could be used as a feedstock for the steel industry. Tailings of the magnetic separation procedure were used to prepare ceramsite. Optimal conditions for preparing ceramsite were: 55% magnetic separation tailings, 20% silica, 15% fly ash, 10% charcoal, a 1150 degrees C roasting temperature, and a holding time of 30min. The ceramsite properties met the requirement of CJ/T299-2008 National Standard. These results suggested that developing this solid waste would have environmental and economic benefits.