Effect Of CaF₂ On Crystallization And Sintering Of Fluorite Tailings Glass Ceramics In CaO-Al₂O₃-SiO₂ System

Fluorite tailings are the parts with lower CaF2 content obtained through the beneficiation process during the production of fluorite.It is characterized by high SiO2 content,mass ratio is generally more than 80%,contains a small amount of Al2O3,CaO,K2O,etc.,it is an essential component for the preparation of CaO-Al2O3-SiO2 glass-ceramics,more SiO2 can make up for glass The problem of insufficient silicon source.The purpose of this study is to use fluorspar tailings to prepare high-grade building decorative materials,glass-ceramics,to achieve high value-added use of fluorspar tailings,and to avoid environmental problems caused by improper handling of fluorspar tailings.In this paper,sintered glass-ceramics were prepared with fluorspar tailings as the main raw materials.The effects of CaF2 on the crystallization and sintering properties of glass-ceramics with different particle sizes were studied,and the properties of the glass-ceramics prepared by adding fluorspar tailings were studied.The study are as follows:(1)According to the content of CaF2 in fluorspar tailings,the five components of the fluorite tailings are A?E,and the mass fraction of CaF2 is in the range of 0?4%.The components A?E are melted at high temperature,the obtained glass particles have particle sizes of 1000?m to 4000?m and 48?m to 75?m.(2)The glass particles were subjected to DTA experimental analysis to obtain the initial crystallization temperature(Tcs)and the crystallization peak temperature(Tp).The samples with different particle sizes were treated under different temperature regimes,and the obtained samples were separately subjected to XRD analysis,SEM analysis,infrared spectrum analysis,crystallization kinetics analysis,etc.,the glass particle size in the range of 48?m?75?m,the crystallization effect is better.(3)The melting point and melting velocity of five groups of powder glass with particle size of 48?m?75?m were analyzed.The sintering experiment was carried out and the sintering morphology was observed.The sintering activation energy was calculated to determine the better sintering temperature system.(4)Based on the CaF2 content introduced,formulate F,G,and H components,add fluorspar tailings at 47wt%,57wt%,and 67wt%,the glass particle size range from 48?m?75?m.According to the powder Glass-ceramic sintering system.Fluorite tailings glass-ceramics respectively for XRD analysis,SEM analysis,infrared spectrum analysis and density test,microhardness test and so on,to get the best components of glass-ceramics.According to the above experiments,the optimum addition amount of fluorspar tailings obtained in this paper is 57%,and the selected basic glass particle size is 48?m?75?m.The best heat treatment system is as follows:sintering temperature is 1000?,sintering time is 1h,and heating rate is 10?/min,the density of the resulting fluorite tailings glass-ceramics was 2.71g/cm3 and the microhardness was 668 HV.