硅灰石制备二氧化硅材料的酸解过程研究

Study on the Acid Hydrolysis Process During Synthesizing Silica Materials with Natural Wollastonite

采用 XRD和化学分析方法研究了三斜晶系普通硅灰石制备二氧化硅材料中的酸解过程。酸解产物的 XRD分析表明 ,酸解反应过程中 ,三斜晶系普通硅灰石除被转变成 m Si O2 · n H2 O外 ,其晶体结构存在向单斜晶系副硅灰石、针钠钙石型结构和硬硅钙石和傅硅钙石的晶型转变 ,6 0 min前以形成单斜晶系副硅灰石的多型转变为主 ,6 0 m in后则以形成针钠钙石型结构、硬硅钙石和傅硅钙石为主。盐酸浓度和反应温度对硅灰石酸解过程的影响研究发现 ,硅灰石快速酸解反应的盐酸浓度不宜高于 4 m ol/ L ,将反应温度维持在

The acid hydrolysis process during synthesizing silica materials with natural wollastonite, which is of a triclinic cell, was investigated with XRD and chemical analysis methods. It was confirmed by the XRD result that the silicon-oxygen tetrahedron chain of investigated wollastonite with triclinic cell had been reconfigured as that of wollanstonite with monoclinic cell and calcium silicate hydrates during the acid hydrolysis, besides transforming into mSiO 2·nH 2O. The polytype transformation of wollastonite from triclinic cell to monoclinic cell mainly took place during the first 60 min and the hydration reaction that form pectolite-type calcium silicate hydrate, xenotlite and foshagite was significantly reinforced between 60～120 min. The ceiling concentration of chlorhydric acid for the fast acid hydrolysis of natural wollastonite should never be more than 4 mol/L on the base of effect of concentration of chlorhydric acid in the range 1~6 mol/L on the acid hydrolysis of wollanstonite. It is necessary for the process control of the acid hydrolysis of wollanstonite to keep the reaction temperature at about 30 ℃.