Pyrolysis of Waste Steel Tailings and Iron Recovery

Pyrolysis has recently received much attention as a promising technology for recycling all the valuable materials from wastes. This study investigated the thermal degradation behaviors of the waste steel tailings and the recovery of iron from waste steel tailings using magnetic separation after pyrolysis. Thermogravimetric (TG) and differential thermogravimetric (DTG) analyses were performed to study the mass loss characteristics. The main pyrolysis temperature range of the waste steel tailings was approximately from 100 to 800 degrees C and the total mass loss was about 30%. The pyrolysis process of waste steel tailings could be classified into four stages. The optimum pyrolysis temperature and pyrolysis time of waste steel tailings were at 700 degrees C for 60 min. The pyrolysis residues generated during the process under optimal condition were detailed analyzed by X-ray powder diffraction (XRD). The result showed that the phase composition of iron in the pyrolysis residues was magnetite. The results of magnetic separation showed that the recovery of iron was 92.66%.