纤蛇纹石短纤维去金属氧化物制备纤维状多孔二氧化硅

Preparation of Fibri-Form Porous Silica by Extracting Metal Oxide from Short Chrysotile Fibers

基于纤蛇纹石一维纳米管结构和形态属性,以石棉尾矿中纤蛇纹石短纤维为原料,采用酸浸法去金属氧化物,获得纤维状多孔SiO2,并对不同去金属氧化物作用阶段产物的形貌、物相组成和谱学特征进行表征。结果表明,去金属氧化物作用(以MgO浸取率表征)优化的工艺条件为:硫酸溶液质量分数35%,反应温度90℃,反应时间2.00h,液固比10∶1。纤蛇纹石结构中的金属氧化物组分被去除后,仅保留具有石棉纤维形态的非晶态SiO2。在纤蛇纹石去金属氧化物作用过程中,氢氧镁石八面体片结构组元被去除的同时,原位保留和修饰了硅氧四面体片结构组元,形成了纤维状多孔SiO2。

Based on the structure and form of one-dimensional nanotube chrysotile,a fibri-form porous silica was prepared with short chrysotile fibers from chrysotile asbestos tailing as a raw material by an acid leaching method.The morphology,phase and spectral characteristics were characterized.The results show that the optimum efficiency of extracting metal oxide is obtained at the concentration of sulfuric acid of 35%(mass fraction),the leaching temperature of 90℃,the leaching time of 2h and the ratio of liquid-solid of 10∶1.The oxides(i.e.,MgO,Al2O3 and Fe2O3)in the short chrysotile fibers are removed and only the amorphous SiO2 with the fiber morphology is remained after the extraction.In the process of extracting metal oxides,the magnesia octahedral sheets are removed,which can retain and modify the Si—O tetrahedral sheets in chrysotile.