酸浸粉煤灰提取铝铁工艺研究

Technology process of extraction of aluminium and iron from fly ash by acid leaching

粉煤灰中的铝、硅以复杂的玻璃体红柱石形式存在,酸溶性非常差,必须破坏S iO2-A l2O3键,使粉煤灰中的铝活化,提高粉煤灰的酸溶性。研究了以CaF2为助剂焙烧活化粉煤灰和酸溶提取铝铁的条件,考察了粉煤灰焙烧活化和盐酸溶出条件对粉煤灰中铝铁浸出率的影响。实验表明,焙烧活化条件为:CaF2用量为1%、粉煤灰与石灰石的质量比为2.5、焙烧温度为850℃、烧成时间2 h;酸溶的最佳工艺条件为:溶出温度为85℃、溶出时间为2.0h、盐酸浓度为7mol/L、液固比为3.5,粉煤灰中铝铁溶出率高达90.5%。

Complex vitreous mullite phase,the existence form of aluminum-silicon containing fly ash,was hardly soluble in acidic solutions,the SiO2-Al2O3 bond was effectively destroyed to activated aluminum,acid-soluble was raised.The conditions of roasting activation of fly ash with CaF2 as assistant and extraction of aluminium and iron by acid leaching were studied,the effects of conditions of roasting activation and acid leaching on the leaching rate of aluminium and iron from fly ash were investigated,The experimental results show that the conditions of roasting activations were obtained as：CaF2 dosage1%,mass ratio fly ash to limestone 2.5,roasting temperature 850℃,roasting time 2h;the best technological conditions were as follow： under liquid-to-solid ratio 3.5,an aluminum and iron leaching efficiency of 90.5% was achieved when modified fly ash was leached with hydrochloric acid using an acid concentration of 7mol/L at 85℃ for 2 h.