Purification Research Of Powder Quartz In Guangnan County Yunnan Province

Powder quartz is smaller in particle size,easier to process and wider in application range,compared to traditional siliceous materials such as quartzite,vein quartz and quartz sand.The deep processing of powder quartz is relatively simple. The demand of ultrafine powder quartz with high purity is increasingly greater during the development of electronic industry.In order to obtain ultrafine powder quartz with high activity and purity,it is necessary to study the purification technology of powder quartz deposit.Firstly,in this paper,mineralogical characteristics of powder quartz deposit which located in Yunnan province were studied.Results indicated that the raw powder quartz sample is mainly composed of quartz,clay minerals（mainly kaolinite and illite） and a tiny amount of feldspar.The content of quartz is about 85%,and the total amount of clay minerals is about 15%.This powder quartz deposit has the characteristics of high weathering degree,simple mineral composition and small particle size.Impurity minerals,i.e.kaolinite,illite and feldspar,exist in the powder quartz sample as separate particles,inclusions in quartz or aggregations with quartz. Characterizations suggest that this powder quartz deposit is formed by long-term,high degree and incomplete weathering of feldspathic or felsic rocks.The scrubbing-sedimentation experiment results show that the suitable dispersant of scrubbing is sodium polyacrylate.The optimum conditions of scrubbing experiment are dosage of dispersant=0.15%,scrubbing time=20min and slurry concentration of powder quartz=60～68%.The content of SiO₂ of obtained powder quartz sample is about 98.5%.The experiments of using stirred mill grinding-scrubbing-multi-sedimentation are carried on purification of powder quartz according to mineralogical characteristics of quartz powder deposit and scrubbing-sedimentation experiment.That optimum process parameters are mass of quartz powder=300g,mass of water=150g,dosage of dispersant=0.15%,ball-to-powder weight ratio=4:1,grind speed=1200rpm,grind time=30min.The particle size of ground quartz powder is about 600mesh.Then the concentration of ground quartz powder is adjusted to nearly 15%.The times of scrubbing-sedimentation are four,and each sedimentation time is 2h,and the dosage of dispersant is 0.1%during the sedimentation.In this method,the SiO₂ content of obtained powder quartz samples is 99.5%,and the Al content is about 0.08%.The scrubbing powder quartz is crushed to 600mesh,and Separated three times by usingΦ25 hydrocyclone.The SiO₂ content of obtained powder quartz is between 99.0%and 99.6%.The obtained powder quartz with 99.6%SiO₂ content is crushed to 1250mesh, and then Separated three times by usingΦ10 hydrocyclone.The underflow is again separated one time byΦ25 hydrocyclone.The SiO₂ content of obtained underflow powder quartz is above 99.9%.