Study On The Resource Utilization And Adsorbability Of Silica Fume

Adsorption process is one of the important physical and chemical methods to treat industrial effluents. The current industrial adsorbents mainly include activated carbon, activated alumina and diatomite, etc. Based on the resource utilization of silica fume (SF) which is a by-product of ferrosilicon industry, the preparation process of new adsorption material was studied in details. The adsorption material was made from silica fume with some of binders and pore-creating agents, and its adsorption effect on methyl orange and iron-containing liquid were also studied in this paper.Research on increasing specific area of SF by acid leaching treatment was done firstly and the best way to increase surface area of silica fume was determined. The experimental results showed that the specific area of treated SF could reach 71.252m2/g with the addition of 1% HF acid solution to SF, keeping the solid to liquid ratio at a level of 4g/100mL and leaching the SF for 30min at a temperature of 70℃. The specific area of SF was significantly increased, which was good for the expansion of its application performance.Two methods to preparing SF adsorption material were studied, and the optimal technical parameters were determined secondly. The first process took sintered clinker of SF and calcined CaO as raw material. The experimental results demonstrate that when the molar ratio of SF to CaO was 1:1, the calcination temperature was 1100℃and the burning time was 30min, a clinker can be obtained in a muffle furnace. Then 50% of silica and 15% of starch were added and mixed. The absorption material was finally obtained after extrusion and sintered at a temperature of 550℃for 30min. When the absorption material was used to treat methyl orange and iron-containing liquid waste, the results showed that the decolorization rate was 51% on the methyl orange and the iron removal rate of 40.2% in wastewater. The other process prepared absorption material by SF which was leached by HF acid. Taking certain amount of HF for the leaching treatment of SF, mixing with 50% of silica and 15% of starch well, making into strips by extrude, the absorption material was prepared after sintered at a temperature of 550℃for 30min. When the absorption material was used to treat methyl orange and iron-containing liquid waste, the results showed that the decolorization rate was 68.8% on the methyl orange and the iron removal rate of 63.5% in wastewater.Finally, the performance of SF adsorbing material was analyzed and characterized. The pore structure, surface topography, preparation method, strength and regeneration of adsorbing material were mainly discussed.