短纤维石棉制备纤维状SiO_2的原理与方法

Study on Principle and Technology of Preparation of Fibriform SiO_2 from Chrysotile

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S iO2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S iO2、MgO和H2O+,其质量分数S iO2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S iO2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S iO2纤维残骸;经后处理即可获得纤维状S iO2纳米材料。

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.