基于TIMA分析的新疆蒙其古尔铀矿床地浸前后脉石矿物工艺矿物学对比研究

COMPARISON OF PROCESS MINERALOGY OF GANGUE MINERALS BEFORE AND AFTER IN-SITU LEACHING OF MENGQIGUER URANIUM DEPOSIT IN XINJIANG BASED ON TIMA ANALYSIS

蒙其古尔铀矿床位于伊犁盆地南部,是碳酸盐含量较高的可地浸层间氧化带砂岩型铀矿床。本次研究采用了自动矿物分析系统(TIMA)来对CO_(2)+O_(2)地浸前后脉石矿物连生、解离度和粒度变化进行分析,反映了脉石矿物在中性地浸过程中对铀浸出的影响,对铀矿地浸工艺矿物学研究有着重要意义。分析表明,浸出前,铀石与沥青铀矿、黄铁矿、正长石及石英连生程度分别为19.31%,18.82%,14.86%,12.19%,而沥青铀矿与铀石的连生程度则为89.16%。浸出后,两件样品铀石与正长石的连生程度分别增至31.47%和45.09%;石英的连生程度变为10.08%及17.60%;沥青铀矿降至1.69%和0.00%;黄铁矿则降低为0.00%。与沥青铀矿相连生的铀石在浸出后连生占比分别降为53.85%和0.00%。黄铁矿、石英、铀石和沥青铀矿等4种矿物小于10%解离度的矿物颗粒所占比例在浸出前后均有所增大,指示解离度减小;正长石则反之。粒度方面,浸出后正长石、黄铁矿、铀石和沥青铀矿等小于50μm的颗粒所占比例增多,指示粒度有减小趋势,而石英粒度变化则不太明显。综上,中性浸出过程中黄铁矿和正长石产生了溶蚀现象,这会阻碍铀的迁移与浸出;石英对铀的浸出没有显著的影响;而沥青铀矿与铀石被有机质和粘土矿物包裹是其难以浸出的原因。

The Mengqiguer uranium deposit,located in the southern part of the Yili Basin,is characterized as a sandstone-type uranium deposit with a high carbonate content in the leachable oxidation zone.This paper employs the TESCAN Integrated Mineral Analysis(TIMA)to scrutinize changes in gangue mineral association,dissociation degree,and particle size before and after CO_(2)+O_(2)in-situ leaching.This analysis unveils the impact of gangue minerals on uranium leaching during the neutral in-situ leaching process,offering significant insights for the mineralogical research of uranium leaching.Prior to leaching,the association degrees between coffinite and pitchblende,pyrite,orthoclase,and quartz are measured at 19.31%,18.82%,14.86%,and 12.19%,respectively.In contrast,the association degree between pitchblende and coffinite is notably higher at 89.16%.Post-leaching,the association degree between coffinite and orthoclase increases to 31.47%and 45.09%,respectively,while the association degree of quartz becomes 10.08%and 17.60%.In contrast,the association degree of pitchblende decreases to 1.69%and 0.00%,and pyrite is completely reduced to 0.00%.The proportion of coffinite associated with pitchblende after leaching significantly decreases to 53.85%and 0.00%,respectively.Examining the dissociation degree,it is observed that the proportion of mineral particles with less than 10%dissociation degree of pyrite,quartz,coffinite,and pitchblende increases both before and after leaching,indicating a reduction in the dissociation degree,except for orthoclase.Regarding particle size,after leaching,the proportion of orthoclase,pyrite,coffinite,and pitchblende particles smaller than 50μm increases,suggesting a decreasing trend in particle size.In contrast,the change in quartz particle size is not significant.In summary,the dissolution of pyrite and orthoclase during the neutral leaching process impedes the migration and leaching of uranium.Quartz has no significant effect on uranium leaching.Additionally,the recognition that organic matter and clay minerals wrapping around pitchblende and coffinite diminishes leaching efficiency,making the extraction of uranium minerals challenging.These findings provide valuable insights into optimizing the neutral leaching process for enhanced uranium recovery.