陕西某河湖相沉积型天然石英砂工艺矿物学研究

Process Mineralogy of Natural Quartz Sand Deposited by River and Lake Facies in Shaanxi Province

以陕西某河湖相沉积天然石英砂为研究对象,通过XRD、XRF、EPMA、光学显微镜等现代测试技术进行系统的研究。结果表明:该石英砂脱泥后的SiO_(2)含量为84.54%,杂质元素主要为Al、K、Na、Fe等;矿物主要为石英,脉石矿物为钠长石、钾长石、绢云母及赤(褐)铁矿等。偏光显微镜下砂粒主要可分为岩屑砂粒和石英等矿物单体砂,单体矿物砂粒占70%,岩屑砂粒占30%。岩屑砂粒可进一步分为石英岩岩屑、燧石岩屑、云母石英片岩岩屑、石英砂岩岩屑、千枚岩岩屑;单体矿物砂粒主要是石英,少量的长石类。擦洗分级后的精砂破碎率(应力28 MPa)为8.5%,平均球度为0.72,平均圆度为0.68,浊度为30.25FTU,满足石油行业用支撑剂标准。

Taking the natural quartz sand of a river and lake deposit in Shaanxi as the research object,the quartz sand was systematically studied by modern testing techniques such as XRD,XRF,EPMA and optical microscope.The results showed that the SiO_(2) content of the quartz sand after desilting was 84.54%,and the impurity elements were mainly Al,K,Na,Fe,etc.The minerals were mainly quartz,and the gangue minerals were albite,potassium feldspar,sericite and hematite.Under the polarizing microscope,the sand particles could be mainly divided into lithic sand particles and quartz and other mineral monomer sand particles.The monomer mineral sand particles accounted for 70%,and the lithic sand particles accounted for 30%.Debris sand could be further divided into quartzite debris,flint debris,mica quartz schist debris,quartz sandstone debris,phyllite debris;the monomeric mineral sand particles were mainly quartz,with a small amount of feldspar type.The crushing rate(stress 28 MPa)of fine sand after scrubbing classification was 8.5%,with the average sphericity 0.72,the average roundness 0.68,and the turbidity 30.25 FTU,which met the standard of proppant for petroleum industry.