## 3 Results and Discussion
### Basic Glass Differential Thermal Analysis
The prepared cylinders were placed in corundum boats and transferred to a high-temperature furnace, the temperature was increased to 950 \({}^{\circ}\)C in one step at a rate of 10 \({}^{\circ}\)C/min, and the microcrystalline glass samples were obtained by cooling in the furnace after holding for 0.5, 1, 2, 3 and 4 h.  
The XRD patterns for the microcrystalline glass products prepared by holding for different times at the optimal crystallization temperature are displayed in Figure 4:0 The crystalline phase species of the microcrystalline glass did not change with the increase in the crystallization time from 0.5 h to 4 h. The main crystalline phases of the microcrystalline glass obtained at different crystallization times all constituted the anorthite phase (CaAl\({}_{2}\)Si\({}_{2}\)O\({}_{8}\)). However, when the crystallization time was increased to 1 h and more, the diffraction peak of the halocite feldspar was enhanced compared with that at a crystallization time of 0.5 h. This indicated that the content or crystallization degree of  
Figure 4:1 Effects of the crystallization temperature on the acid and alkali resistances of the microcrystalline glass. the crystalline phase of the microcrystalline glass increased, while the peak intensity of the chalcocite feldspar was slightly enhanced after 1 h. Thus, the crystallization degree of the crystalline phase was slowly enhanced by the continuing extension of the crystallization time after 1 h. The extension of the crystallization time did not affect the crystalline phase type of the microcrystalline glass; however, a reasonable extension of the crystallization time improved the degree of crystallization of the microcrystalline glass. Figure 11 displays SEM images of the microcrystalline glass prepared at different crystallization times. When the crystallization time was 0.5 h, the crystallization degree of the sample was low, the number of glassy phases was larger, the grain size was uneven and the number was small, the grains were irregularly distributed, and the internal structure of the microcrystalline glass was random and contained defects such as pores. This can be attributed to the short crystallization time, the small number of grains, and the incomplete growth of the nuclei, which resulted in an insufficient crystallization of the prepared microcrystalline glass. With the extension of the crystallization time, the crystallization drive of the sample was enhanced, the number of crystals increased, and the growth of the nuclei was complete [27]. When the crystallization time was extended to 1 h, the glass phase in the microcrystalline glass sample disappeared and a large number of spherical grains with different sizes ranging within 100-200 nm was generated. The grains generated in the samples were more closely arranged and tended to gather into clusters; however, small holes were observed in the samples. When the crystallization time was further extended to 3 h, some spherical grains in the sample transformed into rods, thereby increasing the density of the sample structure and enhancing the performance of the microcrystalline glass. However, when the crystallization time was extended to 4 h, the spherical grains and rod-like grains in the sample disappeared. In addition, a mesh structure formed in the sample increased the contact area of the glass with the acidic and alkaline solutions and considerably reduced the acid and alkali resistances of the sample, thereby resulting in a decrease in its chemical stability. Figure 12 illustrates the effects of crystallization time on the density of the prepared microcrystalline glass. The density of the microcrystalline glass first increased and then decreased with the extension of the crystallization time. When the crystallization time was extended to 3 h, the density reached its maximum value of 2.72 g/cm\({}^{3}\); when the crystallization temperature was further extended to 4 h, the density of the microcrystalline glass decreased.