Extraction Of Silicon From Silicon Dregs And Experimental Study On Preparation Of White Carbon Black

The silicon slag is a kind of solid waste that is synthesised by bauxite and sulfuric acid under pressure conditions when the water treatment agent(Al2(SO4)3)is produced.The silicon slag is mainly used for production of cement,ceramic tile and so on nowdays.But resources waste and environment pollution is caused,on account of poor quality of these products and accumulation of the majority of the silicon slag due to low utilization rate of these usage,The composition of silicon slag is mainly by silicon element,a small number of Al Ti element and so on,it can be used to produce silicon-containing products.This paper has been studied the technology of producing white carbon black of the high purity.The main method is that silicon slag was calcined with the activator-Na2Co3 to activate raw material at high temperature and leached by water then it was used as the raw material to prepare the silica product by sulfuric acid precipitation method.A new kind of technology of processing silicon slag is obtained.The optimum technical conditions of calcine-leaching silicon slag were as follows:calcination temperature of 800? activator-Na2CO3 addition amount of 35 g,calcination time of 20 min,liquid to solid ratio of 7:1,leaching temperature of 90?,leaching time of 1.5 h,stirring speed of 300 r/min,the lotion volume of 30 ml/times,the SiO2 dissolution rate of 79.13%,the Al2O3 dissolution rate of only 8.24%,and the TiO2 dissolution rate of 47.95%.The second order response surface model of the silica dissolution rate fitted with the response surface method is accurate and reasonable,and can be used for the analysis and prediction of the silica dissolution rate in the silicon slag.The interaction of calcination temperature-the amount of anhydrous sodium carbonate and the leaching temperature silica dissolution rate is very significant.Considering the dissolution rate and cost of silica,the process parameters for determining the dissolution rate of silica were optimized:the calcination temperature of around 850?,anhydrous sodium carbonate of about 35 g,and the leaching temperature of 90?.The conditions of the leaching of raw materials were further verified.The leaching solution was obtained under the optimum extraction conditions was treated by using sulfuric acid precipitation method in order to produce white carbon black.The optimum conditions are as follows:the reaction temperature of 80?,the end point of reaction of pH=4,the reaction time of 1.0 h,the calcination temperature of 700?,the calcination time of 30 min,and the stirring speed rate of 200 r/min.The products were characterized by FTIR,XRD,BET,SEM,SEM-EDS and XPS.The qualitative and quantitative analysis results show that the prepared product is indeed white carbon black.The purity of the obtained silica is 95.07%,the whiteness is 92.90%,the specific surface area is 29.38 m2/g,the pore volume is 0.36 m3/g and the pore size is 31.05 nm.The paper has been studied a technology for white carbon black produces with high purity and large market demand.First of all silicon slag that after alkaline calcination is leached in the water,the precipitate that is leaching from water should be washed dried calcined and so on.The innovation of the paper is in the point of processing technology and choosing silicon sources.The paper topic belongs to the solid waste resources recycling technology and waste treatment question of silicon slag enterprise may be solved,so the obvious social efficiency and the economic efficiency can be expected.