Recovery of high specific area silica and sodium fluoride from sodium hexafluorosilicate  

作　　者：徐徽 李贵 程俊峰 刘卫平 

机构地区：[1]School of Metallurgy and Environment Central South University

出　　处：《Journal of Central South University》2014年第11期4084-4090,共7页中南大学学报（英文版）

摘　　要：Sodium fluoride and high specific area silica were synthesized by using sodium hexafluorosilicate(Na2Si F6) and sodium carbonate decahydrate(Na2CO3·10H2O). The influencing factors of react temperature, contact time, sodium dodecyl sulfate(SDS) and molar ratio of Na2 Si F6 to Na2CO3·10H2O were investigated. The optimum process involves the reaction of 0.075 mol Na2 Si F6 and 150 m L, 0.225 mol Na2CO3·10H2O(molar ratio of 1:3) at 85 °C for 90 min, and 2.0×10-3 mol sodium dodecyl sulfate(SDS) as additive. The results show that the purities of Si O2 and Na F at extraction yields of 96.5% and 98.0% are 91.0% and 98.6%, respectively. The obtained Si O2 were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), Fourier transform infrared ray(FTIR), differential scanning calorimetry and thermogravimetric analysis(DSC-TGA), N2 absorption/desorption(BET) and laser particle size analyzer. The result demonstrates that Si O2 particles have a high BET surface area of 103 m2/g, and a mean grain size of 985 nm.Sodium fluoride and high specific area silica were synthesized by using sodium hexafluorosilicate（Na2Si F6） and sodium carbonate decahydrate（Na2CO3·10H2O）. The influencing factors of react temperature, contact time, sodium dodecyl sulfate（SDS） and molar ratio of Na2 Si F6 to Na2CO3·10H2O were investigated. The optimum process involves the reaction of 0.075 mol Na2 Si F6 and 150 m L, 0.225 mol Na2CO3·10H2O（molar ratio of 1：3） at 85 °C for 90 min, and 2.0×10-3 mol sodium dodecyl sulfate（SDS） as additive. The results show that the purities of Si O2 and Na F at extraction yields of 96.5% and 98.0% are 91.0% and 98.6%, respectively. The obtained Si O2 were characterized by X-ray diffraction（XRD）, scanning electron microscope（SEM）, Fourier transform infrared ray（FTIR）, differential scanning calorimetry and thermogravimetric analysis（DSC-TGA）, N2 absorption/desorption（BET） and laser particle size analyzer. The result demonstrates that Si O2 particles have a high BET surface area of 103 m2/g, and a mean grain size of 985 nm.

关 键 词：recovery sodium hexafluosilicate sodium fluoride silica 

分 类 号：O613.72[理学—无机化学] O614.112[理学—化学]