Abstract: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.