粉煤灰综合利用硫酸浸取铝、铁试验

Experiment on sulfuric acid leaching of aluminum and iron for comprehensive utilization of coal ash

试验采用硫酸进行粉煤灰浸出,考察主要工艺条件对粉煤灰中Al、Fe浸出率的影响,并且对浸出渣进行成分和物相分析,试验结果表明:硫酸高温酸浸粉煤灰可实现Al、Fe元素高效浸出,浸出温度为主要影响因素;在浸出温度230℃、硫酸质量分数20%、反应时间120 min、液固比10∶1的酸浸条件下,Al的浸出率为89.43%,Fe的浸出率为69.78%;酸浸渣的主要化学成分为SiO_(2),含量为79.1%,同时含有少量未浸出的Al_(2)O_(3)、Fe_(2)O_(3),可作为生料原料制备硅酸盐水泥熟料。该试验中无二次废渣排放,且浸出液的后续处理也无废液排放,此方法为实现粉煤灰的综合利用和零排放提供了参考依据。

Coal ash leaching test was conducted using sulfuric acid,for the purpose of investigating the influence of the main process conditions on the leaching rate of Al and Fe in the coal ash,meanwhile the compositions and phase of the leaching residue were analyzed.The test results showed that:high-temperature acid leaching of coal ash using sulfuric acid could achieve a high-efficiency leaching of aluminum and iron elements,and the leaching temperature was the main influencing factor;under the acid leaching conditions of leaching temperature 230℃,sulfuric acid mass fraction 20%,reaction time 120 min,and liquid-solid ratio 10∶1,the leaching rate of Al was 89.43%,and the leaching rate of Fe was 69.78%;the main chemical composition of the acid leaching residue was SiO^(2),its content was 79.1%,and it also contained a small amount of unleached Al_(2)O_(3) and Fe_(2)O_(3),which could be used as raw materials to prepare Portland cement clinker.There was no secondary waste residue discharge in this test,and no waste liquid discharge in the subsequent treatment of the leachate.The method provided a reference for realization of comprehensive utilization of coal ash with zero discharge.