(1. 中國鋁業(yè)股份有限公司 鄭州研究院，鄭州 450041；2. 中南大學(xué) 化學(xué)化工學(xué)院，長沙 410083；
3. 深圳市海盈科技有限公司，深圳 518104)
摘 要: 研究了高嶺石、伊利石、葉蠟石等幾種單體硅礦物在鋁酸鈉溶液中的溶出行為。結(jié)果表明，高嶺石、伊利石、葉蠟石等單體硅礦物在鋁酸鈉溶液中的溶出速率受溫度等反應(yīng)條件的影響。采用量子化學(xué)理論計算，用CASTEP程序模塊，在GGA-PW91基組水平，對高嶺石、伊利石、葉蠟石及其常見完全解理面(001)slab模型進(jìn)行幾何優(yōu)化，揭示了高嶺石、伊利石、葉蠟石在鋁酸鈉溶液中反應(yīng)活性差異的微觀本質(zhì)。高嶺石、伊利石和葉蠟石的反應(yīng)活性存在較明顯的不同，其中葉蠟石的反應(yīng)活性最大。伊利石的Si—O鍵結(jié)合力最強(qiáng)，Al—O鍵結(jié)合力相對最弱，相對最難反應(yīng)脫Si；葉蠟石Si—O鍵結(jié)合力相對最弱，相對較容易反應(yīng)脫除Si。OH−的存在對高嶺石、伊利石、葉蠟石完全解理面的微觀電子結(jié)構(gòu)、Si—O鍵的結(jié)合力等均影響顯著，其中OH−對高嶺石表面性質(zhì)及 Si—O鍵結(jié)合力的降低產(chǎn)生的影響最大，因此高嶺石在相對較低溫度下較易在堿性溶液中反應(yīng)脫硅。
關(guān)鍵字: 硅礦物；氧化鋁；拜耳法溶出；鋁酸鈉溶液；反應(yīng)活性；行為
（1. Zhengzhou Research Institute, Aluminum Corporation of China Limited, Zhengzhou 450041, China;
2. School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China;
3. Shenzhen Herewin Technology Co., Ltd, Shenzhen 518140, China）
Abstract:The digestion behaviors of several mono-silicon minerals including kaolinite, illite, pyrophyllite in aluminate solution were investigated. The results show that the digestion rate of kaolinite, illite and pyrophyllite in aluminate solution is influenced by reaction conditions such as temperature. By adopting quantum chemistry theoretical calculation, and using CASTEP procedure module, the slab model of kaolinite, illite, pyrophyllite and their ordinary complete cleavage plane (001) are geometry optimized at GGA-PW91 level. The micro-essence of the differenent reaction activity among kaolinite, illite and pyrophyllite in aluminate solution is opened out. The reaction activity of kaolinite, illite and pyrophyllite is obviously different and the reaction activity of pyrophyllite is the highest. The Si—O bond strength of illite is the strongest and its Al—O bond strength is comparatively the most weak, so its Si is the most difficult to remove. The Si—O bond strength of pyrophyllite is the most weak, so its Si is relatively easier to remove. The micro-electron structure of complete cleavage plane and the Si—O bond strength of kaolinite, illite and pyrophyllite are evidently influenced by the existence of OH−, of which the surface character and the reduction of Si—O bond strength of kaolinite are influenced most by OH−, therefore the desilication of kaolinite in alkaline solution at relatively lower temperature is easier.
Key words: silicon minerals; alumina; Bayer digestion; aluminate solution; reaction activity; behavior
