Na2O-Al2O3-Fe2O3系烧结过程中铝、铁的反应行为

以Al2O3, Fe2O3和Na2CO3为原料，对Na2O-Al2O3-Fe2O3系烧结过程中的反应行为进行了详细研究. 基于溶出率与时间、温度的关系，证明Na2O×Al2O3和Na2O×Fe2O3的生成反应动力学都服从Zhuralev-Lesokin-Tempelman模型，表观活化能分别为186.59和80.92 kJ/mol，表明Na2O×Fe2O3比Na2O×Al2O3在动力学上更易形成；Al2O3易与Na2O×Fe2O3反应形成Na2O×Al2O3和Fe2O3，在1273 K烧结30 min，所得熟料Al2O3溶出率达98.51%；Fe2O3对Na2O×Al2O3的形成有双重作用，在1273 K下可加速Na2O×Al2O3的形成，超过1323 K，促使Na2O×Al2O3分解成Na2O和b-Al2O3，且随着温度升高或时间延长，分解程度增高，从而导致熟料中Al2O3溶出率显著降低.

Reaction Behavior of Al2O3 and Fe2O3 in Na2O-Al2O3-Fe2O3 Systems during Sintering

The reaction behavior of Al2O3 and Fe2O3 in Na2O-Al2O3-Fe2O3 system was investigated in detail with Al2O3, Fe2O3 and Na2CO3 as raw materials. Both Na2O×Al2O3 and Na2O×Fe2O3 formation reactions are in accordance with the Zhuralev-Lesokin- Tempelman diffusion-controlled model in kinetics based on the relationship between Al2O3/Na2O extraction rate and sintering temperature or time, and the apparent activation energy is 186.59 and 80.92 kJ/mol, respectively, and the formation of Na2O×Fe2O3 is prior to that of Na2O×Al2O3. The results also indicate that Al2O3 reacts easily with Na2O×Fe2O3 in sintering process, and Na2O×Al2O3 and Fe2O3 occur in clinker. For example, Al2O3 extraction rate of the clinker reaches to 98.51%. Fe2O3 has double effects on the formation of Na2O×Al2O3. On the one hand, it can accelerate the formation of Na2O×Al2O3 at 1273 K. But on the other hand, at the temperature higher than 1323 K, Fe2O3 can accelerate the decomposition of Na2O×Al2O3 due to the decrease of Al2O3 extraction rate in clinker leaching operation and existence of b-Al2O3 in residue, and temperature increasing or time prolongation favors the reaction between Fe2O3 and Na2O×Al2O3.