745矿生物浸矿过程中铀矿物的变化

Variation of Uranium Minerals in Bioleaching of Mine 745

采用电子探针分析了浸出前后745铀矿物赋存形式及其变化情况.结果表明,该矿床矿石中铀矿物种类比较单一,主要以沥青铀矿为主,其次为铀石、铀钍石和钛铀矿;铀矿物主要以不规则树枝状或细脉状、颗粒状、星点状产出于矿物裂隙中,少部分被其它矿物包裹;粒度多在10μm以上、大者可达100μm以上.生物浸矿后,尾渣中剩余的铀矿物明显减少,残存的铀矿物种类仍然是沥青铀矿、铀石和钛铀矿,但粒度多在1～2 μm以内,主要存在于石英颗粒内.说明裂隙中的沥青铀矿与铀钍石容易被浸出,被石英包裹的铀则难以被浸出.

Electronic microprobe technique was applied to analyze Mine 745 uranium ores and tailings in terms of their mineralogy and chemistry, and according variations before and after bioleaching. The results show that uranium minerals from the mine are mainly consisted of pitchblende, with a small portion of colfinite, uranothorite and brannerite. Those uranium minerals species mainly present themselves in occurrences of irregular dendritic or thin vein, granular, star-shape in mineral fractures, with some wrapped in other minerals. The particle size is relatively big ranging from 10μm to 100 μm above. After bioleaching, the uranium content in tailings evidently reduce, although the species, mainly presented inside the quartz grains with the size of 1-2μm, remain the same. The results indicate that pitchblende and uranothorite in fissures are easily leached while those wrapped in quartz grains are hard to leach.