Industrial Symbiosis: High Purity Recovery of Metals from Waelz Sintering Waste by Aqueous SO sub(2) Solution

• Published in: Journal of hazardous materials Vol. 149; no. 2; p. 303
• Main Authors: Copur, Mehmet, Pekdemir, Turgay, Colak, Sabri, Kunkul, Asim
• Format: Journal Article
• Language: English
• Published: 22.10.2007
• ISSN: 0304-3894
• DOI: 10.1016/j.jhazmat.2007.03.079

Sintering operation in the production of Zn, Cd, and Pb by Waelz process produces a powdery waste containing mainly (about 70%) ZnO, CdO, and PbO. The waste may be referred to as Waelz sintering waste (WSW). The aim of this study is to develop a process for the separation and recovery of the metals from WSW with high purities. The process is based on the dissolution of the WSW in aqueous SO sub(2) solution. The research reported here concentrated on the effect of some important operational parameters on dissolution process. The parameters investigated and their ranges were as follows: SO sub(2) gas flow rate (V); 38-590ml/min, stirring speed (W); 100-1000rpm, reaction temperature (T); 13-60 super(o)C, reaction time (t); 1-16min, and solid-liquid ratio (S/L); 0.1-0.5g/ml. The results showed that the dissolution rate increased with increasing W, V, and S/L and decreasing T. The best dissolution conditions were found to be V=325ml/min, W=600rpm, t=6min, T=21 super(o)C, and S/L=0.1g/ml. Separation of Zn from Cd involved precipitation of ZnSO sub(3) from a mixture solution. The best pH level for the precipitation was observed to be 6.