Dissolution Behavior of Aluminum, Silicon, and Iron of Diaspore Concentrate in NaOH–NaAl(OH)4 Solutions at Elevated Temperature
Dissolution Behavior of Aluminum, Silicon, and Iron of Diaspore Concentrate in NaOH–NaAl(OH)4 Solutions at Elevated Temperature
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DOI：
10.1021/ie402867n
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发表时间：
2013-12
影响因子：
4.2
通讯作者：
Lan-mu Zeng;Zhibao Li
中科院分区：
文献类型：
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作者：
Lan-mu Zeng;Zhibao Li
研究了一水硬铝石精矿在浓NaOH-NaAl（OH）（4）溶液中的高温溶解行为。氢氧化钠浓度和温度的增加能显著提高铝的溶解速率，而氢氧化铝的加入则降低了铝的溶解速率。随着反应时间的延长，主要杂质Si的浓度不断降低，而Fe的浓度保持在一个有限的水平。Lasaga（Lasaga，A. C. Kinetic Theory in the Earth Science; Princeton University Press：Princeton，NJ，USA，1998）应用于基于K-sp（一水硬铝石）和溶液中相关物质的活度系数来模拟Al的动力学行为。所得到的动力学模型能够预测铝在拜耳液中的溶解速率。在473.2 ~ 543.2K温度范围内，溶解反应的表观活化能为83 kJ·mol（-1）。
The high temperature dissolution behavior of diaspore concentrate was measured in concentrated NaOH-NaAl(OH)(4) solutions. The dissolution rate of Al was greatly found to be enhanced by increasing NaOH concentration and temperature while decreased with addition of Al(OH)(3). The concentration of Si as the main impurity constantly decreases with reaction time while the Fe is retained at a limited level. The generalized rate law for mineral dissolution and precipitation, proposed by Lasaga (Lasaga, A. C. Kinetic Theory in the Earth Science; Princeton University Press: Princeton, NJ, USA, 1998), was applied to model the kinetic behavior of Al on the basis of K-sp(diaspore) and the activity coefficients of related species in the solution. The resulting kinetic model was capable of predicting the dissolution rate of Al in the Bayer liquor. The apparent activation energy of the dissolution reaction over the temperature range from 473.2 to 543.2 K was estimated at 83 kj.mol(-1).