温石棉尾矿活化产物制备纳米SiO_2实验研究

Research on Preparation of SiO_2 Nano-particles by Activation Products of Chrysotile Asbestos Tailings

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。

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 Na2SiOa 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%.