热活化―酸浸法提取煤矸石中铝和铁的实验研究

Experimental study on the extraction of aluminum and iron from coal gangue by thermal activation and acid leaching method

煤矸石作为煤炭开采和洗选过程中的伴生固体废弃物,每年的排放量较大,不仅会浪费土地资源,还会对生态环境造成影响。由于煤矸石中富含Fe_(2)O_(3)、Al_(2)O_(3)等金属氧化物,因此从中提取铁和铝是煤矸石资源化利用的一个重要途径。采用热活化-酸浸法提取煤矸石中Fe^(3+)和Al^(3+),通过单因素实验,以液固比、硫酸浓度、酸浸时间和酸浸温度为实验变量,研究其对Fe^(3+)和Al^(3+)浸出率的影响。在此基础上,利用Design-Expert 13和Box-Behnken进行响应面优化实验,并建立了高拟合度的回归模型。结果表明,Fe^(3+)和Al^(3+)的最佳浸出条件为酸浸温度91.71℃、硫酸浓度2.84 mol·L^(−1)、液固比5.90∶1 mL·g^(−1)以及酸浸时间3.04 h,Fe^(3+)、Al^(3+)浸出率分别为66.039%、35.844%,为煤矸石资源利用提供一定的参考价值。

A massive amount of coal gangue(an accompanying solid waste)is produced during coal mining and washing processes,leading not only to the wastage of land resources but also to environmental impacts.Due to the abundant presence of metal oxides such as Fe_(2)O_(3)and Al_(2)O_(3)in coal gangue,the extraction of iron and aluminum from it serves as a crucial pathway for the resource utilization of coal gangue.In this study,a thermal activation-acid leaching method was used to extract Fe^(3+)and Al^(3+)from coal gangue.Through single-factor experiments,with variables including liquid-tosolid ratio,acid concentration,acid leaching time,and acid leaching temperature,the influence of these factors on the leaching rates of Fe^(3+)and Al^(3+)was investigated.Subsequently,response surface optimization experiments were conducted using Design-Expert 13 and Box-Behnken methods,and a regression model with a high fitting degree was established.The results of the regression model indicated that the optimal conditions for leaching Fe^(3+)and Al^(3+)were as follows:Acid leaching temperature of 91.71℃,acid concentration of 2.84 mol·L^(−1),liquid-to-solid ratio of 5.90∶1 mL·g^(−1),and acid leaching time of 3.04 h.Under these conditions,the leaching rates of Fe^(3+)and Al^(3+)were 66.039%and 35.844%,respectively.These findings provide a valuable reference for the resource utilization of coal gangue.