( 中南大學(xué) 冶金科學(xué)與工程學(xué)院， 長(zhǎng)沙 410083)
摘 要: 對(duì)鋁酸鈉溶液碳酸化分解過(guò)程的動(dòng)力學(xué)進(jìn)行了研究。在對(duì)碳酸化分解過(guò)程中的氫氧化鈉被二氧化碳中和以及氫氧化鋁析出兩個(gè)過(guò)程進(jìn)行比較后， 認(rèn)為整個(gè)碳酸化分解過(guò)程是受氫氧化鋁析出過(guò)程控制， 仍然遵循種分機(jī)理。 借鑒種分過(guò)程動(dòng)力學(xué)模型，給出了動(dòng)力學(xué)方程。 方程表明： 碳酸化分解反應(yīng)的表觀活化能為75.115kJ/mol，這與晶種分解過(guò)程的活化能大致相當(dāng)， 也與碳酸化分解過(guò)程仍然遵循晶種分解機(jī)理的觀點(diǎn)相吻合； 碳酸化分解過(guò)程強(qiáng)烈地受到過(guò)飽和度的影響。
關(guān)鍵字: 鋁酸鈉溶液； 碳酸化分解； 氫氧化鋁； 動(dòng)力學(xué)
PENG Zhi-hong， LIU Xiang-min
（ College of Metallurgical Science and Engineering,
Central South University,Changsha 410083, China）
Abstract: The kinetics of carbonation decomposition of sodium aluminate solution was investigated. Based on the camparison between the two essential processes in carbonation decomposition—one is the reaction between sodium hydroxide and carbon dioxide, the other is the process of aluminum trihydroxide precipitation, it is revealed that the latter is the controlling step. With the seeded precipitation model in the literature, the model of kinetics of carbonation decomposition and its corresponding kinetic equation were deduced. The results show that the apparent activation energy of carbonation is 75.115kJ/mol, which serves as a well indication of the similarity on mechanism between the process of carbonation and that of seeded precipitation process. The effect of seed on carbonation precipitation can be well explained only when the concept of instantaneous seed is employed to the kinetic equation. The process of carbonation precipitation is intensively affected by super-saturation.
Key words: sodium aluminate solution； carbonation decomposition； aluminum trihydroxide； kinetics
