Study on Economic Recovery and Utilization of Effective Alkali in Alumina Production System
In the production of alumina by the Bayer process,after each cycle of the mother liquor,the caustic alkali is lost and the invalid alkali is increased,resulting in a decrease in the efficiency of evapo-ration and salt discharge,and an increase in energy consumption and alkali consumption.In order to re-cover the lost caustic alkali and reduce the invalid alkali,this paper took the domestic diaspore alumina production system with high carbon content as an example,and designed three process conditions:evapo-ration salt discharge causticization,evaporation salt discharge causticization+red mud dealkalization and recovery,evaporation salt discharge causticization+red mud dealkalization and recovery+first washing solution causticization.The flow direction of Na2O in the production process was studied,and the loss,conversion and recovery of effective alkali in the system were calculated.From the technical and econom-ic aspects,the characteristics of red mud alkali removal and causticization of primary lotion were analyzed and compared.The dealkalization of red mud can remove and recover the Na2O in the sodium silicon slag of red mud and return it to the production system.The causticization of the first lotion can convert Na2CO3 in the mother liquor into NaOH and reduce the carbon-alkali content of the system.Dealkaliza-tion of red mud and causticization of primary lotion can reduce the alkali consumption of alumina produc-tion and save production costs.Taking an alumina plant with a capacity of 100 t/a as an example,the al-kali consumption of production can be reduced by 66～70 kg/t by using red mud alkali removal and caus-ticization of primary washing liquid,and the production cost of alumina can be saved by 85～134 yuan/t.
aluminasoda recoverysoda removal and recovery from red mudfirst washing liquor caus-ticization
万方数据
维普
