钙化焙烧-酸浸工艺提取钼精矿中铼的研究

利用热力学计算软件Factsage7.0对Ca-Mo-Re-S-O体系进行了热力学分析, 结果表明, 钙化焙烧的适宜温度区间为600~625 ℃, 此时有利于减缓Re₂O₇的挥发, 生成易溶于稀硫酸的钼酸钙, 从而提高钼和铼的综合回收率。针对钼品位39.27%、铼品位340 g/t的含铼低品位钼精矿, 采用钙化焙烧-酸浸法, 研究了CaO、Ca(OH)₂、CaCO₃等钙添加剂对铼综合回收率和固硫率的影响, 结果表明, 钙添加剂Ca(OH)₂的硫保留率和铼综合回收率在三者中最优; 焙烧温度625 ℃, Ca(OH)₂与钼精矿质量比为1∶1时指标较优, 铼综合回收率可达79.51%, 固硫率达91.49%。

Extraction of Rhenium from Molybdenum Concentrates by Calcification Roasting and Acid Leaching

Thermodynamic analysis of the Ca-Mo-Re-S-O system was conducted with Factsage 7.0. Result shows that the temperature range of 600~625 ℃ is suitable for the process of calcification roasting, in which the volatilization of Re₂O₇ is prone to slowing down, leading to the formed calcium molybdate (CaMoO₄) soluble in H₂SO₄, thus resulting in an improvement in the comprehensive recoveries of molybdenum and rhenium. Based on the test for low-grade molybdenum concentrate containing 39.27% molybdenum and 340 g/t rhenium by using calcification roasting and acid leaching process, effects of three kinds of calcium-based additives, such as CaO, Ca(OH)₂ and CaCO₃, on the comprehensive recovery of rhenium and sulfur capturing rate were investigated. It is found that the additive of Ca(OH)₂ can lead to the best sulfur capturing effect and the highest rhenium recovery. It is shown that at the roasting temperature of 625 ℃, with Ca(OH)₂ to molybdenum concentrate at a mass ratio of 1∶1, the recovery of rhenium can reach 79.51% and the sulfur capturing rate can be up to 91.49%.