The study of lithium silicate preparaed by aerogel from ash

• 1、School of Metallurgical and Ecological Engineering,University of Science & Technology Beijing,Beijing, 100083

Abstract：In this paper, fly ash is used as raw material to synthesize silica-aluminum aerogel by combining alkali fusion and acid leaching with sol-gel method, and lithium silicate is successfully synthesized after calcination at high temperature after mixing with lithium hydroxide monohydrate as silicon source.X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence spectroscopy (XRF) were used to explore the composition and microstructure of raw materials and synthetic phases, and TG instruments were used to test the adsorption capacity of samples at variable temperature and fixed temperature.The influence of calcining temperature on adsorption capacity was investigated.The results show that when the molar ratio of the sample material is 4.1 and the calcination temperature is 600℃, the sample is pure phase lithium silicate and its microstructure is a needle cluster structure, which is conducive to the contact between carbon dioxide and the adsorbent and reduces the diffusion resistance of carbon dioxide.At this point, the adsorption effect is the best. The maximum adsorption capacity reaches 33.5% (91.28% of the theoretical adsorption capacity) after 120min in a pure CARBON dioxide atmosphere, and the equilibrium adsorption time is 45min.

Keywords： Lithium silicate Carbon dioxide adsorption Aerogels Fly ash