Study On Preparation Of Glass-Ceramics From Fly Ash

With the rapid development of industrialization,China has made great progress in aerospace,shipbuilding,military industry,electronics and so on.However,the development is inseparable from the basic power.The power generation of the country is mainly based on thermal power plants,which inevitably causes solid wastes such as fly ash while consuming coal resources.With the accumulation of fly ash,it not only occupies a lot of land resources,but also pollutes the air,which has become an increasingly serious problem.The increasingly prominent resource and environmental problems promote the transformation of industrial sustainable development.Making full use of industrial by-products can not only minimize the consumption of raw materials and energy,but also minimize the impact on the environment and improve economic benefits.The main components of fly ash are SiO₂and Al₂O₃,and a small amount of Fe₂O₃,CaO,MgO and other trace elements.This is similar to the composition of glass ceramics.Therefore,it is of great significance to use fly ash as the main raw material and add some chemical reagents to prepare high value building decoration materials glass ceramics.On the one hand,it solves the solid waste generated by coal combustion,on the other hand,it makes glass-ceramic with high added value,so that the resources can be recycled and reused,which provides a feasible scheme for the future industrial development.In this paper,CaO-MgO-Al₂O₃-SiO₂(CMAS)glass ceramics were prepared by melting method with fly ash as the research object.The basic samples of glass ceramics prepared with fly ash content of 60wt%,65wt%,70wt%,75wt%and 80wt%were studied.The heat treatment process and microstructure of glass ceramics were determined by means of differential thermal analysis(DSC),X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results show that:the heat treatment systems of five groups are determined as follows:the crystallization peak temperature of sample60wt%is 920?,the nucleation temperature is 826?,the crystallization peak temperature of sample 65wt%is 937?,the nucleation temperature is 815?,the crystallization temperature of sample 70wt%is 912?,the nucleation temperature is 808?,the crystallization temperature of sample 75wt%is 925?,the nucleation temperature is 804?,and the crystallization temperature of sample 80wt%.The nucleation temperature was 927?.When the basic glass formula with 80wt%fly ash and1.0wt%Cr₂O₃and 3wt%Ti O₂nucleating agents are added,and the nucleation temperature is 813?,the nucleation time is 1.5h,and the crystallization time is 1.5h,respectively.The maximum flexural strength of the glass ceramics is 100.23Mpa,the highest hardness is 496.25Hv,the lowest water absorption is 0.14,and the corrosion resistance is good It also provides a theoretical support for the preparation of a new material,which is of great significance for the recycling of resources.