摘要：为了减少温石棉尾矿的大量丢弃而造成环境污染与资源浪费,以青海芒崖温石棉尾矿的活化产物为原料,采用碳化法制备纳米二氧化硅,研究Na₂SiO₃溶液浓度、碳化时间、碳化温度、碳化终点pH值及表面改性剂用量对纳米SiO₂形成的影响。采用X射线衍射、X射线荧光光谱分析及扫描电镜对制备的纳米SiO₂样品的物相、化学成分及颗粒形貌进行表征。结果表明:当Na₂SiO₃溶液浓度为0.6 mol/L、碳化时间50 min、反应温度为70℃、碳化终点pH值为8.5左右、表面改性剂质量分数为0.6%时,可制备出粒度为50 nm左右的球状无定形纳米SiO₂,且w(SiO₂)=99%,同时,纳米SiO₂的转化率达77%以上。

关键词： 温石棉尾矿；碳化；纳米二氧化硅

Abstract： In order to decrease the environmental pollution and the waste of resources by a large number of abandoned chrysotile asbestos tailings， the activation products of chrysotile asbestos tailings from Mangya， Qinghai Province were used as the raw materials to prepare SiO₂ nano-particles by carbonation method. The influence of Na₂SiO₃ solution concentration， carbonization time， carbonization temperature， the pH value of end carbon and use level of surface modification agent on the formation of SiO₂nano-particles were studied. The phase， chemical composition and particle morphology of SiO₂ nano-particles were characterized by XRD， XRF and SEM. The results showed that the optimal experimental conditions were that the solution concentration of Na₂SiO₃ was 0.6 mol/L， carbonization time was 50 min， carbonization temperature was 70 ℃ ， the pH value of end carbon was 8.5 and the mass fraction of surface modification agent was 0.6%. So the spherical amorphous SiO₂ nano-particles were prepared and the particle size was about 50 nm， the purity was 99% . Meanwhile， the conversion rate of SiO₂ nano-particles was more than 77%. 

Keywords： chrysotile asbestos tailings； carbonation； SiO₂ nano-particles