温石棉尾矿活化产物制备纳米SiO_2实验研究

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。

Research on Preparation of SiO2 Nano-particles by Activation Products of Chrysotile Asbestos Tailings

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 SiO2 nano-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%.