Technology and mechanism of valuable metal recovery from pyrite cinder by chloridizing roasting

摘要

A new technology of pellet production-drying-chloridizing roasting is proposed for valuable metal recovery from pyrite cinder with high content of lead and zinc. The pyrite cinder, containing 60.15% Fe, 2.02% Pb and 2.15% Zn, was pelletized with addition of 2% bentonite in pan pelletizer. Green balls after drying were roasting at 1100°C for 60 min with 5 wt% of CaCl_2 addition in tube furnace. The results demonstrate that pellets with 61.58% of TFe, lead and zinc volatile ratios of 98.02% and 96.83% were obtained. Key technique is that CaCl_2 reacts with lead and zinc compounds and the chloride can be volatilized at moderate temperatures. This new technology can recover the valuable metal fully from pyrite cinder and produce qualified concentrate as iron-bearing feed for steel industry, which will help to solve the pollution of pyrite cinder and extend raw material sourcing for Chinese steel industry.