低品位氧化钼钨精矿高温高压碱浸工艺工业生产实践

Industrial Practices of High-temperature & High-pressure Alkali Leaching of Low-grade Molybdenum-tungsten Oxide Concentrates

内蒙古某钼钨多金属矿主要以氧化钼为主,伴生金和白钨,矿石性质复杂,浮选出的氧化钼钨精矿品位低(MoO33%～5.5%,WO3≤1.5%),为了实现低品位氧化钼钨精矿综合利用,采用高温高压碱浸对低品位氧化钼钨精矿进行处理,利用氯化钙直接沉淀钼钨,得到钨钼酸钙精矿,实验确定了最佳工艺方案和技术条件,经中试和工业生产实践获得了成功。生产结果表明:当纯碱加入量为矿样钼含量的2.3倍,温度175℃,液固比2∶1,浸出时间90 min,钼钨的浸出率可达到99%;当氯化钙加入量为矿样钼含量的2.0倍、沉淀温度70℃、沉淀时间30 min,生产出的钼钨酸钙平均品位为钼35.48%、钨7%,钼回收率96.17%,较好的解决了该多金属矿综合回收利用的技术难题。

A molybdenum-tungsten polymetallic ore in Inner Mongolia predominantly consists of molybdenum oxide associated with gold and scheelite. Such complex properties lead to low grade of molybdenum-tungsten oxide concentrate from flotation （ MoO3 3% - 5.5%, WO3 〈 1.5% ）. In order to fulfill comprehensive utilization of such low-grade molybdenum-tungsten oxide concentrates, a process of high-temperature and high-pressure alkali leaching was adopted. Calcium tungstate-molybdate concentrates were obtained by using calcium chloride to precipitate molybdenum and tungsten directly. Through experiments, the optimal processing program and technical conditions were determined, which has been proved successful by pilot tests and industrial practices. The practices have shown that when the amount of soda is 2.3 times that of molybdenum in the sample ore, with the temperature reaching 175 ~C, the ratio of solid to liquid reaching 1： 2 and leaching time reaching 90 minutes, the leaching rate of molybdenum and tungsten can be up to 99%. When the amount of calcium chloride is 2.0 times that of molybdenum in the sample ore, with the temperature reaching 70 C and the time reaching 30 minutes, the average grade of calcium tungstate-molybdate concentrate is 35.48% and 7% for molybdenum and tungsten, respectively. The recovery rate of molybdenum is 96. 17%. The process has resolved the technical problem of recovering and utilizing the polymetallic ore comprehensively in a good way.