Comprehensive recovery and recycle of jarosite residues from zinc hydrometallurgy

Abstract

In this paper, a new method for the comprehensive recovery and recycle of jarosite residues (JR) is proposed. By direct reduction followed by magnetic separation, lead, zinc and iron are separated and recovered from JR and sulfur is fixed. The non-magnetic tails (NMT) of the magnetic separation is used for removing of Cd, As and Pb heavy metal ions from acidic wastewater of zinc hydrometallurgy. Test work results showed that the volatilization rates of lead and zinc were 96.97% and 99.89%, respectively, the sulfur fixation rate with CaO was 98.91% under optimal conditions of reduced roasting at 1523 K for 60 min. A magnetic iron concentrate was obtained containing 95.68% iron at a recovery of 76.26% by grinding-magnetic separation process. The removal rates of Cd, As and Pb ions were 99.98%, 93.75% and 99.80% respectively. The content of Cd, As and Pb ions in the treated wastewater met the emission standards at 120 g/L NMT dosage and for a contact time of 90 mins. The proposed method is considered as an environmentally-friendly and efficient approach to the comprehensive recovery and recycle of JR and the removal of toxic cadmium, arsenic and lead ions from acidic wastewater of zinc hydrometallurgy.

Keywords

• Jarosite residues
• Separation
• Recovery
• Heavy metal ion adsorption
• Purification