含锂赤泥在硫酸铵溶液中的浸出行为及机理

Leaching behavior and mechanism of lithium-rich red mud in ammonium sulfate solution

对赤泥在硫酸铵溶液中的浸出行为进行研究,在热力学分析的基础上,系统考察浸出温度、硫酸铵浓度、时间以及液固比对赤泥中锂、钠、钾浸出率的影响,并通过浸出前后物相和形貌的变化对其浸出机理进行探讨。研究结果表明:升高温度、硫酸铵浓度和延长时间有助于锂的浸出,而温度过高会降低锂的浸出率;在温度为270℃,时间为60 min,硫酸铵质量浓度为200 g/L,液固比为10:1的条件下,锂、钠、钾的浸出率分别为65.07%,95.97%和28.62%;赤泥在硫酸铵溶液中浸出锂、钠、钾的机理可能是离子置换。

The leaching behavior of red mud in ammonium sulfate solution was studied. Based on the thermodynamic analyses, the effects of leaching temperature, ammonium sulfate concentration, time and liquidsolid ratio on the leaching ratio of lithium, sodium and potassium in red mud were systematically investigated, and the leaching mechanism was discussed by the comparisons of phase and morphology changes before and after leaching. The results show that increasing temperature, ammonium sulfate mass concentration and time can improve the leaching of lithium, while excessive temperature weakens the lithium leaching. Under the conditions of temperature 270 ℃, time 60 min, ammonium sulfate mass concentration 200 g/L and liquid-solid ratio 10:1, the leaching ratios of lithium, sodium and potassium are 65.07%, 95.97% and 28.62%, respectively. The leaching mechanism of lithium, sodium and potassium in ammonium sulfate solution from red mud may be ion substitution.