(中南大學(xué) 化學(xué)化工學(xué)院，化學(xué)工程與技術(shù)博士后流動(dòng)站，長(zhǎng)沙 410083)
摘 要: 研究了二氧化硅對(duì)鋁酸鈉溶液分解過程的分解率、產(chǎn)品粒度及形貌的影響。根據(jù)實(shí)驗(yàn)結(jié)果用基于密度泛函的Dmol3程序計(jì)算SiO32−以各種不同方式位于氫氧化鋁(001)和(100)面時(shí)的總能量和電子結(jié)構(gòu)等，用晶體生長(zhǎng)習(xí)性計(jì)算程序Morphology分析各體系的平衡形態(tài)及生長(zhǎng)習(xí)性。實(shí)驗(yàn)結(jié)果表明：在一定的分解時(shí)間范圍內(nèi)，硅能抑制鋁酸鈉溶液種分分解，對(duì)分解產(chǎn)物氫氧化鋁的晶體形貌有影響，其(100)面的顯露有所增加。理論計(jì)算結(jié)果表明：SiO32−的存在明顯改變氫氧化鋁(001)和(100)表面的電子結(jié)構(gòu)，SiO32−在氫氧化鋁(001)和(100)表面上時(shí)，靠近(001)面的O原子多的體系穩(wěn)定性低。平衡形態(tài)及生長(zhǎng)習(xí)性計(jì)算結(jié)果表明：SiO32−在氫氧化鋁(001)表面上時(shí)，各體系長(zhǎng)大晶粒的體積均小于無SiO32−體系中(001)的晶粒體積；而SiO32−在氫氧化鋁(100)表面上時(shí)，各體系長(zhǎng)大晶粒的體積比均大于SiO32−體系中(100)的晶粒體積。
關(guān)鍵字: 鋁酸鈉溶液；含硅雜質(zhì)；微觀機(jī)制；結(jié)晶習(xí)性
（Postdoctoral Exchange Station of Chemical Engineering and Technologe, School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:By analyzing the changes of precipitation ratio, particle size and morphology, the effect of the impurity ingredient contained silicon on the process of precipitation of sodium aluminate was studied. According to these experimental results, the total energy and electronic structure of SiO32− located on gibbsite (001) and (100) face with some different modes were calculated by using Dmol3 program based on DFT, and the equilibrium and growth morphology of systems were analyzed by using crystal growth habit program morphology. The experimental results show that the silicon dioxide influences the precipitation rate and morphology of gibbsite, and the (100) face of gibbsite is easier to unfold. The theoretic calculation results indicate that the electronic structures of (001) and (100) surface change obviously when SiO32− is located on the surface, and the stability of the system with more oxygen atom is lower. The calculation results of equilibrium morphology and growth habit show that the volume of growth crystal is smaller when SiO32− is located on gibbsite (001) surface, while the volume is larger when SiO32− is located on gibbsite (100) surface, compared with the systems without SiO32−.
Key words: sodium aluminate; silicon-containing impurity; microcosmic mechanism; crystal habit
