微波强化焙烧一水硬铝石矿浸出效果的研究

将一水硬铝石矿和过饱和NaOH溶液及Ca(OH)2混合均匀后在微波炉中焙烧;熟料在稀碱性溶液、常压条件下进行浸出,研究配料比、微波焙烧和浸出条件对熟料浸出的影响。结果表明,升高微波焙烧温度、增加NaOH添加量或延长保温时间都可以增加熟料中铝的浸出率。增加Ca(OH)2添加量可以减少溶液中硅的溶解率,但过量添加Ca(OH)2反而导致铝的浸出效果下降。适当的浸出温度和浸出时间有助于减少二次反应发生,提高铝硅分离效果。在最优试验条件下,熟料中铝、钠、硅的浸出率分别达到96.7%、98.2%和7.05%,赤泥颗粒较大,利于过滤过程。

Leaching Effect of Diasporic Bauxite Assisted by Microwave Enhanced Roasting

Diasporic bauxite was mixed with Ca(OH)2 and supersaturated NaOH solution and roasted in microwave field. The obtained clinker was leached in dilute alkali solution at atmospheric pressure. The influences of mixing-ratio, microwave roasting conditions and leaching conditions on leaching of clinkers were studied. The results show that leaching rate of aluminum of clinker is improved by raising microwave roasting temperature, prolonging holding time or increasing dosage of NaOH. Increasing amount of Ca(OH)2 can gradually drop silicon content in leachate, but excessive addition of Ca(OH)2 leads to reduction of leaching effect of aluminum. Adjusting leaching temperature and time is beneficial for reducing secondary reaction and improving separation effect of aluminum and silicon. Leaching rates of aluminum, sodium and silicon of roasted product is 96.7%, 98.2% and 7.05%, respectively under the optimum conditions. Under these conditions, red mud particles are larger, which is conducive to filtration process.