MINERALOGICAL CHARACTERISTICS OF NEUTRAL IN-SITU LEACHING PROCESS IN THE QIAN Ⅳ BLOCK OF THE QIANJIADIAN URANIUM DE-POSIT,SONGLIAO BASIN
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 sus-tainable development of nuclear energy.Neutral(CO2+O2)ground leaching of uranium has become the leaching technology with the highest proportion of uranium ore in China.In order to study the mineralogi-cal characteristics of CO2+O2 ground leaching process in Qian Ⅳ block of Qianjiadian uranium deposit in Songliao Basin,the reddish brown siltstone of Yaojia Formation was selected as the research object and CO2+O2 leaching experiment was carried out.By means of X-ray Fluorescence(XRF),Inductively Cou-pled Plasma-Mass Spectrometry(ICP-MS),whole rock X-ray Diffraction(XRD),Scanning Electron Mi-croscopy 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 smal-ler,and the particle size is less than 100 μm.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 py-rite.Therefore,in the process of CO2+O2 ground leaching in Qian Ⅳ block of Qianjiadian uranium de-posit,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 ura-nium in its associated pitchblende and further improve the leaching rate of uranium.
CO2+O2 in-situ leachingProcess mineralogyin-situ leaching of uraniumQianjiadian ura-nium deposit
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