某多金属矿选冶过程中铀的赋存状态研究

Study on the occurrence state of Uranium in a polymetallic ore during beneficiation and metallurgy

针对某放射性多金属矿中铀存在形式复杂、工艺矿物学研究基础薄弱、选冶过程中铀元素流失等问题,利用化学分析、光学显微镜、电子探针、AMICS测试等手段,研究了铀元素在原矿中的赋存状态,并追踪其在不同选矿产品及所对应的不同水冶产物中的存在形式及变化规律。结果表明,该多金属矿中,铀元素在选冶不同阶段的各类产物中均主要呈U4+以类质同象形式分布于不同矿物中。其中,原矿中U4+主要替代Zr4+分布于锆石或替代Th4+分布于钍石中;在选冶过程中,大部分铀元素随锆石进入锆精矿,并最终以未充分溶浸的锆石形式残留在浸出渣中。提高锆精矿中锆石回收率、增强锆精矿中锆石在碱熔阶段的转化程度都有利于减少铀元素的流失。

In order to identify the complex existence of uranium in a radioactive polymetallic ore,and solve problems such as weak research foundation of process mineralogy and uranium loss in the process of beneficiation and metallurgy,the occurrence state of uranium in raw ore was studied by means of chemical analysis,optical microscope,electron probe and AMICS test.And the existence form and change rule of uranium in different concentrate products and leaching residue were traced.The results show that uranium is mainly distributed in the form of U^(4+)as isomorphism in different minerals at different stages of beneficiation and leaching.In the raw ore,U4+is mainly substituted for Zr^(4+)in zircon or Th4+in thorium.In the process of beneficiation and leaching,most of the uranium with zircon gather into zirconium concentrate,and finally in the form of undissolved zircon in the residue.Improving the recovery rate of zircon and enhancing the transformation degree of zircon in the alkali melting stage in zircon concentration can reduce the loss of uranium.