(1. 武漢理工大學(xué) 資源與環(huán)境工程學(xué)院，武漢 430070；
2. 武漢理工大學(xué) 礦物資源加工與環(huán)境湖北省重點(diǎn)實(shí)驗(yàn)室，武漢 430070)
摘 要: 采用XRD、XPS、FTIR以及SEM-EDS分析手段對高嶺石和氧化鐵還原焙燒的反應(yīng)過程進(jìn)行研究，并借助堿浸實(shí)驗(yàn)明確還原焙燒產(chǎn)物中二氧化硅固溶體的溶解性，在此基礎(chǔ)上探討二氧化硅固溶體的形成機(jī)理。結(jié)果表明：高嶺石在1000~1150 ℃還原氣氛中單獨(dú)焙燒時(shí)會轉(zhuǎn)變?yōu)闊o定型態(tài)，氧化鐵的添加可將高嶺石在1050~1150 ℃完全轉(zhuǎn)變?yōu)殍F鋁尖晶石和二氧化硅固溶體-石英固溶體和方石英固溶體。此外，石英固溶體和方石英固溶體與天然的石英和方石英具有相似的結(jié)構(gòu)，但在氫氧化鈉溶液中溶出性能有很大的區(qū)別。還原焙燒過程為固相反應(yīng)，氧化鋁會選擇性與氧化亞鐵反應(yīng)并生成鐵鋁尖晶石，受氧化鋁遷移的影響，少量的Fe2+進(jìn)入硅氧四面體中并最終形成二氧化硅固溶體。
關(guān)鍵字: 高嶺石；還原焙燒；鋁酸亞鐵；石英固溶體；方石英固溶體
（1. School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, China;
2. Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Wuhan 430070, China）
Abstract:The reaction behavior of kaolinite and ferric oxide during reduction roasting was systematically studied through the analysis methods of XRD, XPS, FTIR and SEM-EDS, meanwhile, the solubility of free silica in the reduction product was tested by leaching in NaOH solution. Based on the above studies, the formation mechanism of silica solid solution was discussed. The results show that kaolinite is converted into amorphous state during roasting alone at 1000-1150 ℃, while converted into hercynite and free silica, in the forms of quartz solid solution and cristobalite solid solution, during reductively roasting with hematite at 1050-1150 ℃. In addition, quartz solid solution and cristobalite solid solution have the similarity of structure with natural quartz and cristobalite, but have the dissimilarity of solubility in NaOH solution. Due to the solid-state reaction in reduction roasting, the alumina can selectively react with ferrous oxide to form hercynite, meanwhile, small amount of Fe2+ enters into silica tetrahedra, resulting in the formation of silica solid solution.
Key words: kaolinite; reduction roasting; hercynite; quartz solid solution; cristobalite solid solution
