| The sulfur concentrate of Yinshan contains 1.40 g/t of Au, 21.0 g/t of Ag, 0.17% of Cu, 47.08% of S and 41.21% of Fe. It has high economic value, and it will cause waste of resources if it is only used as a sulfur concentrate for sulfuric acid production. The process conditions of "oxidizing roasting-calcination granulation-chlorination roasting" were studied for the sulfur concentrate. The large-scale test results showed that the final metal volatilization rates were 96.72%, 90.91% and 52.48% for Au, Ag and Cu, respectively. The resulted iron pellet contains 60.72% of Fe, and its compressive strength is 2.105 kN which meets the requirements of grade III, realizing the comprehensive recovery of valuable metals in sulfur concentrates. Due to the expansion of the calcination equipment and operation in the plant test, the volatilization rate of copper is far lower than that of the small-scale test, which should consider the difference in practical production. The mechanism analysis showed that necessary measures should be taken to inhibit the decomposition of calcium chloride at lower temperature and improve the utilization rate of calcium chloride. |
