高硅硫铁矿烧渣浸出过程动力学机理

Kinetics of leaching pyrite calcine bearing high silicon in the H_2SO_4-H_2O system

研究了高硅硫铁矿烧渣在硫酸浸出过程中的动力学机理 ,考察了液固比和温度对Fe浸出速率的影响 .实验结果表明 :在液固比γ <4.7时 ,γ对浸出过程几乎没有影响 ;当γ≥ 4.7时 ,增大γ ,浸出率下降 ;硫酸浓度的反应级数为 1.2 2 ;温度对Fe浸出速率的影响较大 ,提高温度有利于Fe的浸出 ;浸出 1h后浸出率能够很好地满足产物层扩散控制收缩核模型 ,即 1+2 (1-x) - 3(1-x) 2 3 =kt;表观活化能为 5 5 .46 9kJ mol.此外 ,通过化学分析和EPMA分析 ,进一步证明了反应被产物层所控制 .

The kinetics of leaching pyrite calcine bearing high silicon in sulphuric acid medium was investigated, and the effects of the ratio of liquid to solid and temperature on the rate of ferrous extraction was studied. When the ratio of liquid to solid is lower than 4.7, the rate hardly changes. On the other hand, when the ratio of liquid to solid is over 4.7, the rate decreases as the ratio increases. The temperature affects the rate of ferrous extraction apparently. With the temperature increasing, the rate increases too. The ratio after 1 h is suitable for the product layer diffusion controlled shrinking core model, which was proved by the chemical and EPMA analysis. A reaction progression of hydrogen ion is 1.222 and an apparent activation energy has been determined to be about 55.469 kJ/mol.