Integrated Extracting Technology Of Aluminum And Lithium In The Coal Ash From The Pingshuo Mine District, China

Lithium is known as new energy-metal and the metal of promoting world’s progress ". Sun et al. (2011) have found that the Lithium (Li) contents have reached an economic grade in the coal at the pingshuo mine, and combustion products also have reached grade of comprehensive recovery with Li, and Al2O3 contents are as high as 48% in the coal ash. So in this paper, Li and aluminum (Al) will be extracted synthetically in order to reduce cost and improve the economic benefit.In this paper, the contents, distribution and occurrence characteristics of Li and Al in the coal from pingshuo mine are briefly researched, The key research is that the coal ash is studied as raw material to extract synthetically Li and Al with the methods of sulfatizing roasting-acid leaching-carbonization-evaporation and crystallization-lithium precipitation and alkali sintering-alkali leaching-carbonization-evaporation and crystallization-lithium precipitation. Besides, how to improve the comprehensive leaching rate of Li and Al in coal ash for the principle, we find the best test conditions by the single factors and orthogonal test, the best experimental conditions as following:(1) Sulfatizing roasting-acid leaching-carbonization-evaporation and crystallization-lithium precipitation:the mass ratio between coal ash and Na2SO4 is 1.0:0.8; the sintering temperature is 1050℃ and sintering time is 60min; the ratio between the quality of the sample and acid liquor volume is 1g:lml during oxidizing roast; the ratio between the quality of the sample and acid liquor volume is 1g:4ml in the acid lixivium; acid leaching temperature is 60℃ and leaching time is 20min; initial temperature of carbonated decomposition is 70-80℃, end temperature is 40℃ or so; The concentration of CO2 gas is 38-40% and access speed is 2.5-3.5 L/min; the temperature of evaporation and crystallization is 40-90℃; freezing temperature is -5-2℃. Li leaching rate is 95.69% and the recovery is 60.00%; Al leaching rate is 86.15% and the recovery is 80.00% under the above conditions.(2) Alkali sintering-alkali leaching-carbonization-evaporation and crystallization-lithium precipitation:the mass ratio between coal ash and Na2CO3 is 1.0:1.5;the sintering temperature is 950℃ and sintering time is 60min; the ratio between the quality of the sample and dilute caustic volume is 1g:40ml during alkali leaching; alkali leaching temperature is 160℃ and leaching time is 120min; Li leaching rate is 85.30% and the recovery is 55.00%; Al leaching rate is 78.77% and the recovery is 68.00% under the above conditions.Finally, the process programs are evaluated on technology and economy. Based on the comprehensive analysis of its economic value, the process scheme which is put forward for the industrial production will bring huge economic benefits, and which is helpful to realize the economic development in a virtuous circle, but also to improve the development of mineral resources and comprehensive utilization, and the development and utilization of these very important strategic resources will have important significance to take international leading position.