松辽盆地钱家店铀矿床钱Ⅳ块中性地浸工艺矿物学特征

MINERALOGICAL CHARACTERISTICS OF NEUTRAL IN-SITU LEACHING PROCESS IN THE QIANⅣBLOCK OF THE QIANJIADIAN URANIUM DEPOSIT,SONGLIAO BASIN

天然铀资源有效利用是保障我国核电与核军工天然铀供给、确保核能可持续发展的重要战略基础。中性(CO_(2)+O_(2))地浸采铀已成为我国铀矿占比最高的浸出开发工艺。为研究松辽盆地钱家店铀矿床钱Ⅳ块CO_(2)+O_(2)地浸工艺矿物学特征,本次研究选取姚家组粉砂岩中铀矿石为研究对象,开展CO_(2)+O_(2)浸出实验模拟,采用XRF,ICP-MS,XRD,SEM-EDS和TIMA等测试方法将原样及试验后的样品进行系统的工艺矿物学对比研究以期为生产实践采铀提供理论支撑。结果表明,与原样品相比,浸出实验后的样品稀土元素含量明显减少(ΣREE含量由187.06×10^(-6)减至105.16×10^(-6));铀浸出率达到59.8%(U含量由131.00×10^(-6)减至52.60×10^(-6));铀矿物粒度变小,粒度集中在<100μm之间;而铀矿物解离度全部<10%,说明仍有被紧密包裹的铀矿物未被浸出。研究区铀的赋存状态以分散吸附态为主,独立铀矿物含量较少,在浸出后发现与黄铁矿等连生的细颗粒铀矿物残存较多。因此,钱家店铀矿床钱Ⅳ块CO_(2)+O_(2)地浸生产采铀过程中需考虑对粒度小和被紧密包裹的铀矿物提取,以及在制备溶浸剂时提高对黄铁矿的氧化效率将与其连生的沥青铀矿中的铀释放出来,从而进一步提高铀的浸出率。

The effective utilization of natural uranium resources is an important strategic basis to ensure the supply of natural uranium for nuclear power and nuclear military industry in China and ensure the sustainable development of nuclear energy.Neutral(CO_(2)+O_(2))ground leaching of uranium has become the leaching technology with the highest proportion of uranium ore in China.In order to study the mineralogical characteristics of CO_(2)+O_(2)ground leaching process in QianⅣblock of Qianjiadian uranium deposit in Songliao Basin,the reddish brown siltstone of Yaojia Formation was selected as the research object and CO_(2)+O_(2)leaching experiment was carried out.By means of X-ray Fluorescence(XRF),Inductively Coupled Plasma-Mass Spectrometry(ICP-MS),whole rock X-ray Diffraction(XRD),Scanning Electron Microscopy with Energy Dispersive X-ray(SEM-EDS)and TESCAN Integrated Mineral Analyzer(TIMA),systematic comparative studies on process mineralogy of the original and tested samples were carried out in order to provide theoretical support for uranium production practice.The results showed that compared with the original sample,the rare earth element content of the sample after leaching experiment decreased significantly(ΣREE content decreased from 187.06×10^(-6)to 105.16×10^(-6)).Uranium leaching rate reached 59.8%(U content decreased from 131.00×10^(-6)to 52.60×10^(-6));The mineral composition of the upper part of feldspar is transformed into clay minerals;The particle size of uranium mineral is smaller,and the particle size is less than 100μm.The dissociation degree of uranium minerals is all<10%,indicating that only tightly packed uranium minerals are left unleached.The occurrence state of uranium in the study area is mainly dispersed adsorption state,and the content of independent uranium minerals is small.After leaching,it is found that there are more fine particles of uranium minerals associated with pyrite.Therefore,in the process of CO_(2)+O_(2)ground leaching in Qian IV block of Qianjiadian uranium deposit,it is necessary to consider the extraction of small particle size and tightly wrapped uranium minerals and the preparation of leaching agent to improve the oxidation efficiency of pyrite,so as to release the uranium in its associated pitchblende and further improve the leaching rate of uranium.