短纤维石棉制备纤维状SiO2的原理与方法

对纤蛇纹石石棉的化学成分、晶体结构、形态特征和活性进行了研究,探讨了纤蛇纹石石棉制备纤维状纳米SiO2的原理,并对试验产物进行了分析.结果表明:纤蛇纹石石棉是天然产出的纳米管状材料,其内管直径为3.5～24 nm,多数小于11 nm,外管直径为16～56 nm,绝大多数在20～50 nm范围内.纯净的纤蛇纹石石棉样品的化学成分主要为SiO2、MgO和H2O ,其质量分数SiO2约为42%,MgO约为42%,结构水H2O 约为13%.纤蛇纹石具有卷管状结构,化学键特点决定了其具有很好的化学活性和可改造性,为制备纤维状纳米SiO2粉体材料创造了基础.纤蛇纹石石棉纤维经酸处理后,MgO等组分被浸取出来转变为硫酸盐,而残留下非晶质纳米SiO2纤维残骸;经后处理即可获得纤维状SiO2纳米材料.

Study on Principle and Technology of Preparation of Fibriform SiO2 from Chrysotile

The chemical compositions,crystal structure,configurational characters and chemical activity of chrysotile were described.The principle and technology of preparing fibriform SiO_2 from chrysotile were studied and then the products were analyzed.The results show that chrysotile is natural nano-tubes.The main chemical compositions of pure chrysotile are SiO_2(about 42%),MgO(about 42%) and H_2O~ (about 13%).The preparation of nano-sized fibriform SiO_2 powder is based on the good chemical activity and reconstruction of chrysotile determined by the characters of coil-form tubes structure and chemical bond.MgO change into their sulfates after acid treatment,and fibriform SiO_2 can be obtained from the remains.