Study On The Preparation And Crystallization Mechanism Of The Pornus Glass—ceramics Based On Tailings

In the present paper, porous glass-ceramics were prepared by powder sintering method. The raw materials included:iron tailings as major raw material, limestone, dolomite, sandstone, soda ash and alumina powder with analytical grade as the regulating materials, calcium fluoride as flux, sodium bicarbonate as vesicant. We researched the effects of the content variation of major oxide of SiO2、CaO、MgO、Al2O3in the based glass and the heat treatment technology on the comprehensive properties of iron tailings porous glass-ceramics.Set the content of iron tailings as40%, a designed Orthogonal experiments L9(34) reflecting the content variation of major oxide of SiO2CaO、MgO、Al2O3was carried out to determine the influence of these oxides on physical properties of prepared glass-ceramics including apparent density, porosity, thermal conductivity and the constituent of main crystalline phase. According to content variation of major oxides for the orthogonal design of L9(34) to preparation based glass within the range for these oxides’ content, ensure the heat temperature was1050℃by DTA curve of the based glass. Glass-ceramics sample were prepared at this temperature. The microstructure of these glass-ceramics was observed by SEM and the phase structure were measured by XRD.The effects of the content of major oxides on the mechanical properties were explored. Ensure the better content of major oxides by means of above method.The glass-ceramics samples were prepared at950℃、1000℃、1050℃、1100℃1150℃and1200℃, the heat processing was decided by DTA curve which determine by one content of major oxide. To researched the samples’ properties to analyzed the effects of the heat treatment temperature on the mechanical properties. The reasons for the changes of the performance were also explored. The best technological parameters of the heat treatment on glass-ceramics were decided.The results indicated that the intensity of diffraction peak of porous glass-ceramics was enhanced, indicating more crystal phase was formed with the increasing ratio of CaO/MgO and the heat treatment temperature was1050℃. With increasing content of SiO2and decreasing of Al2O3, the apparent density decreased, the porosity increased, and the thermal conductivity decreased. No obvious change of apparent density was detected with the variation of CaO and MgO content. The porosity first increased and then decreased with the increasing weight percentage of CaO and MgO. The major crystalline phase of porous glass-ceramics consisted of diopode, which was not affected notably by the variation of SiO2、CaO、MgO、Al2O3contents. The porosity first increased and then decreased, the apparent density first reduced and then increased,thermal conductivity first reduced and then increased when the sintering temperature was increased.When the sintering temperature was1050℃, the sample’s porosity reached a maximum, the apparent density and the thermal conductivity reached a minimum. The acid resistance and alkali resistance were enhanced with the sintering temperature was increased.