Study On The Technology Of Treating Red Mud With Copper Slag

Red mud is a strong basic metallurgical slag generated in the alumina production process.Due to lack of economically feasible comprehensive treatment technology,it can only be stacked.It poses a great threat to the ecological environment,and is an industrial solid waste to be solved urgently.For the comprehensive treatment of red mud,red mud produced from a plant in Shanxi via the treatment of removal sodium was used as raw material.The carbon thermal reduction process that red mud was treated by copper slag has been proposed and iron resources in these two kinds of industrial solid wastes can be recovered.Through adjusting the chemical composition,the tailings extracted iron were transformed into glass in the form of slow cooling.In the study,the effects of reduction temperature,reduction time,the added amount of copper slag,and the added amount of reducing agent on iron recovery were investigated.And a pilot test of 100 kg was carried out under the optimal experimental conditions.Finally,the vitrification experiment of 100 kg tailings extracted iron was carried out.The main conclusions are as follows:(1)The optimal experimental conditions of carbon thermal reduction:reduction temperature of 1500℃,reduction time of 20 min,added amount of copper slag of 50%,and added amount of reducing agent of 9%.The content of total iron in tailings was 6.89%.(2)During the carbon-thermal reduction process,the transformation of iron-bearing phases is as follows:calcineurite(Ca3Fe2(SiO4)3)→cerroolivine(Fe2SiO4)→calcineurite(CaFeSi2O6).(3)For pilot test,the contents of total iron and metallic iron in the tailings were 3.19%and 0.81%,respectively.The results were better than those of laboratory experiments.This is because the cooling ratio in the pilot test is slow.Thus,reduction and settlement time is long enough,and the calcarenite facies(CaFeSi2O6)was transformed into calcarenite facies(Ca2MgSi2O7).(4)The phase analysis results of the pilot test show that scandiumt exist in the phase of calcium and magnesium feldspar,vanadium and chromium was enriched in iron.(5)Through adjusting chemical composition,the tailings extracted iron can be converted into glass in the form of slow cooling.The cooling rates were 1,2,4,5,6,7,8,and 10℃/min,respectively.