四川什邡式磷矿床中、重稀土元素富集规律及资源潜力——以绵竹清平磷矿为例  

Enrichment regularity and resource potential of medium and heavy rare earth elements in Shifang-type phosphorite deposits,Sichuan:A case study of Qingping phosphorite deposit in Mianzhu

作　　者：代作文 谢玉玲[1] 徐航航 曲云伟 秦绪岩 DAI Zuo-wen;XIE Yu-ling;XU Hang-hang;QU Yun-wei;QIN Xu-yan(Civil and Resource Engineering School,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学土木与资源工程学院,北京100083

出　　处：《岩石矿物学杂志》2024年第5期1175-1187,共13页Acta Petrologica et Mineralogica

基　　金：国家重点研发计划项目(2021YFC2901703)。

摘　　要：什邡式磷矿床是我国重要的磷矿类型,其以矿床规模大、矿石磷品位高和富含稀土元素为特征。然而,对该类型矿床中稀土元素的富集规律及资源潜力尚缺乏详细的研究。本文以四川绵竹典型的什邡式磷矿床——清平磷矿为研究对象,在野外地质调研基础上,对矿区含磷层(磷块岩层、深灰色和褐红色富硫-磷-铝-锶层)和顶、底板岩石(白云岩)开展系统的显微岩相学、扫描电镜/能谱分析和全岩地球化学分析,探索矿床中稀土元素的分布和富集特征,并在此基础上揭示四川什邡式磷矿床中伴生的稀土资源潜力。结果显示,清平磷矿顶、底板白云岩稀土元素(La~Lu+Y)含量低(平均13.6×10^(-6)),磷块岩稀土元素含量中等(平均280.0×10^(-6)),而富硫-磷-铝-锶层稀土元素高度富集(平均2053.9×10^(-6)),尤其是褐红色富硫-磷-铝-锶层(高达3257.2×10^(-6))。结合前人已有的分析数据,四川什邡式磷矿床中的富硫-磷-铝-锶层的稀土元素含量平均为2259.4×10^(-6),最高达3286.8×10^(-6),其中的中、重稀土元素(Sm~Lu+Y)平均为1276.9×10^(-6),最高达2213.0×10^(-6),在稀土元素总量中的占比高,达55.1%,远高于华南离子吸附型稀土矿、织金磷矿中伴生的稀土元素以及富稀土元素的深海沉积物。初步估算,四川什邡式磷矿床伴生的总稀土元素潜在资源量达25.2万吨,其中的中、重稀土元素含量达15.6万吨,仅富硫-磷-铝-锶层中伴生的中、重稀土元素就高达9.6万吨。因此,四川什邡式磷矿床具有重要的经济和社会价值,对其中的中、重稀土元素的开发利用将有望缓解我国中、重稀土元素资源短缺的现状。Shifang-type phosphorite deposit is an important type of phosphorite deposit in China,which is charac-terized by large scale,high phosphorus grade,and enrichment in rare earth elements(REEs).However,the enrichment regularity and resource potential of REEs in this type of deposit are not studied in detail.This study takes the typical Shifang-type phosphorite deposit in Mianzhu,Sichuan Province,as the research object.Based on field geological investigation,the distribution and enrichment characteristics of REEs in the deposit are explored through microscopic petrographic observation,scanning electron microscope/energy disperse spectroscopy imaging,and whole-rock geochemical analysis for the phosphorus-bearing layers(phosphorite layer,dark grey and maroon S-P-Al-Sr-rich layers)and their roof and floor rocks(dolomite)in the mining area.In turn,the potential resource of REEs in Shifang-type phosphorite deposits in Sichuan Province is discussed.The results showed that the total REEs(La-Lu+Y)contents in the roof and floor dolomites of the phosphorus-bearing layers are very low(13.6×10^(-6) on average),the REEs contents in the phosphorite are medium(280.0×10^(-6) on average),while the REEs contents in the S-P-Al-Sr-rich layers are extremely high(2053.9×10^(-6) on average),especially the maroon S-P-Al-Sr-rich layer(up to 3257.2×10^(-6)).Together with previously published REEs content data from adjacent phos-phorite deposit,the average REEs content in S-P-Al-Sr-rich layers in the Shifang-type phosphorite deposits in Si-chuan Province is 2259.4×10^(-6) with the maximum up to 3286.8×10^(-6),of which the average concentration of me-dium and heavy REEs(Sm~Lu+Y)is 1276.9×10^(-6) with the maximum up to 2213.0×10^(-6),accounting for 55.1%of the total REEs.REEs contents in the Shifang-type phosphorite deposits in Sichuan Province are much higher than those in ion adsorption-type REEs deposits in southern China,Zhijin REEs-bearing phosphorite deposit,and REEs-rich deep-sea sediments.According to preliminary estimates,the to

关 键 词：什邡式磷矿床 清平磷矿 稀土元素 绵竹 四川 

分 类 号：P619.213[天文地球—矿床学]