红土镍矿常压盐酸浸出工艺及其动力学研究

采用盐酸在常压下浸出红土镍矿, 考察了矿石粒度、酸料比、反应温度、反应时间、固液比、氯离子浓度对镍、钴、锰等金属浸出率的影响, 得到了该实验下的优化条件为:矿石粒度为0.125～0.15 mm、酸料比为3∶1、反应温度80 ℃、反应时间1 h、固液比为1∶4、不外加氯化盐。在优化条件下的浸出结果表明, 各金属的浸出率分别为Ni 86.9%、Co 67.8%, Fe 86.5%、Mn 80.1%、Mg 58.5%、Cr 72.6%。对不同反应温度下的镍、铁的浸出率-时间曲线进行拟合, 结果表明该浸出过程不符合广泛采用的收缩核模型, 而用Avrami方程拟合则很好地符合其线性关系。浸出过程中镍、铁的活化能分别为72.125 kJ/mol和88.566 kJ/mol。

Atmospheric Leaching of Nickel Laterite by Hydrochloride Acid and Its Kinetics

Nickel laterite was treated by atmospheric leaching with hydrochloride acid. Effects of particle size of laterite, acid/ore ratio, temperature, reaction time, solid/liquid ratio and concentration of chloride ions on the leaching rates of Ni, Co and Mn were investigated. The optimum conditions were as follows: ore particle size of  0.125～0.15 mm, acid-ore ratio of 3∶1, reaction temperature of 80 ℃, reaction time of 1 h, solid-liquid ratio of 1∶4 and no addition of chlorides. Under the optimum conditions, the leaching rates of main metals were Ni 86.9%, Co 67.8%, Fe 86.5%, Mn 80.1%, Mg 58.5% and Cr 72.6%, respectively. Through fitting leaching rate-time curves of nickel and iron at different reaction temperatures, it was found that the leaching process does not fit the shrinking core models widely adopted, while it can be satisfactorily represented by fitting with Avrami models. The activation energy of nickel and iron in the leaching process were 72.125 kJ/mol and 88.566 kJ/mol, respectively.