川滇黔地区峨眉山玄武岩风化壳中铌元素赋存状态研究

Study on the Occurrence State of Niobium in the Weathering Crust of Emeishan Basalt in the Sichuan-Yunnan-Guizhou Province

川滇黔地区峨眉山玄武岩分布区,发育含铌玄武岩风化壳。本文通过典型样品铌元素赋存状态研究发现:(1)X射线衍射分析指出,未检测出铌的独立矿物,主要矿物为高岭石,占比75.4%;次为赤铁矿,占比9.52%。(2)透射电镜分析表明,样品矿物组成为锐钛矿、金红石、钛铁矿、磁铁矿、赤铁矿(褐铁矿)、钾长石、高岭石等,未检测到含铌的独立矿物。(3)铌化学物相分析显示,峨眉山玄武岩风化壳中,铌主要赋存于铌铁矿中,Nb_(2)O_(5)占比为78.05%;次为烧绿石、钛铁金红石、易解石及分散相,Nb_(2)O_(5)占比分别为7.88%、7.39%、3.86%及2.61%,极少量的铌钙矿,Nb_(2)O_(5)占比约0.21%。初步揭示了川滇黔地区峨眉山玄武岩风化壳中铌元素赋存状态,对该类型资源评价与利用有一定指导意义。

The weathering crust of niobium-bearing basalt has been developed in the Emeishan basalt area in the Sichuan-Yunnan-Guizhou Province.The study of the occurrence state of niobium in typical samples in this paper reveals that:(1) X-ray diffraction analysis indicats that no independent mineral of niobium was detected.The dominated mineral is kaolinite,accounting for 75.4%;the secondary mineral is hematite,accounting for9.52 %.(2) Transmission electron microscopy analysis shows that the mineral compositions of the sample include anatase,rutile,ilmenite,magnetite,hematite (limonite),potassium feldspar,kaolinite,etc.Independent minerals of niobium were not detected.(3) The chemical phase analysis of niobium show that niobium mainly occurs in the columbite in the weathering crust of Emeishan basalt,with Nb_(2)O_(5) accounting for 78.05%.The secondary minerals are pyrochlore,ilmenorutite,eschynite,and dispersed phases,with Nb_(2)O_(5) accounted for7.88%,7.39%,3.86%.and 2.61%,respectively.A small amount of fersmite accounted for about 0.21% of Nb_(2)O_(5)This study preliminary reveals the occurrence state of niobium in the weathering crust of Emeishan basalt in the Sichuan-Yunnan-Guizhou area,which has certain guiding significance for the evaluation and utilization of this type of resource.