Study Of Preparation Of Water Glass And Silica White From Huainan Fly Ash By Wet Process

This paper, in the view of environmental protection, energy saving and waste utilization, take huainan coal fly ash as a research object through the experiment, discuss the optimum process conditions of water glass and white silica which use huainan fly ash as a raw material. This paper will provide technical reference for huainan fly ash’s comprehensive development. I argue that:1. After grinding, the particle size, the weight of screen residue and bulk density of fly ash get smaller while the true density of fly ash get bigger. The grinding process destroyed the hard surface of fly ash and stimulated the fly ash’s potential activity. Through the experiment, we can come to a conclusion that the best grinding time is120min.2. When roasted with (NH4)2SO4, the activation temperature of fly ash get lower. The optimal condition of roasting is:the quality ratio of (NH4)SO4and fly ash is3.5:1, roasting time is2h and roasting temperature is500℃. Acid leaching process can leach the majority metal ions from fly ash when use H2SO4as medium. The best condition is that the concentration of H2SO4is15%,(L/S)1is4:1, reaction time is2h, reaction temperature is90℃. After roasting and acid leaching, the content of SiO2is85%.3. The fly ash after roasting and acid leaching can be used as a raw material to produce water glass. The optimal scheme is that NaOH’s concentration is15%, liquid-solid ratio is3:1, reaction time is3h and reaction temperature is80℃. The optimal modulus of water glass is2.5.4. The preparation of white silica takes water glass as raw materials. The added NaCl and n-butyl alcohol can improve the surface performance and the dispersion of white silica, The best condition is that add NaCl and N-butyl alcohol into20%of water glass firstly, and then heat up the temperature to80, keep warm for2hours, and age, wash, dry, We can get the product of white carbon black. The DBP of it is2ml/g.