晶化温度对白云鄂博东尾矿微晶玻璃析晶及性能的影响∗

摘要

利用白云鄂博东尾矿和粉煤灰为主要原料，添加少量石英砂、氧化钙等化学原料，制得了高性能的CaO-MgO-Al2 O3-SiO2(CMAS)系尾矿微晶玻璃，研究了微晶玻璃制备过程中的核化及晶化处理条件对其微观结构及性能的影响。首先通过 DTA、XRD、SEM 及 HRTEM 等测试手段对微晶玻璃的析晶过程进行了表征。结果表明，适当的核化处理温度可使微晶玻璃中产生磁铁矿晶核，这些晶核可作为异质表面促进主晶相辉石相的析出。性能测试结果表明微晶玻璃的密度、抗折强度及耐酸度与微晶玻璃晶化温度有关，晶化温度为850℃的微晶玻璃试样结晶程度最高、综合性能最优。更高的晶化温度导致微晶玻璃中空隙及缺陷的产生，反而降低了其物化特性。%High quality glass-ceramics in the CaO-MgO-Al2 O3-SiO2 system were prepared from the Baiyunebo east mine tailing and fly ash as main raw material added a small amount of quartz sand,calcium oxide and other chemi-cal raw materials.The processing schedule for nucleation and crystallization on the microstructure and properties of the glass-ceramics were investigated.The crystallization behavior of these glass ceramics have been investigated by dif-ferential thermal analysis (DTA),X-ray diffraction (XRD),scanning electron microscope (SEM)and high resolution transmission electron microscopy (HRTEM).The results confirmed the magnetite can appear in the initial stages of nucleation at the appropriate nuclear temperature.These first nano-crystals of magnetite could then form heteroge-neous surfaces for subsequent crystallization of augite.Mechanical measurements showed that bending strengths,den-sity and chemical durability of glass-ceramics were related to the crystallization temperature.The glass-ceramic with crystallization temperature of 850 ℃ showed highest degree of crystallization,which can result in higher bending strengths and acid-resistance.Higher crystallization temperature can result in the appearance of voids and defects in glass-ceramics,which can decrease the physical and chemical properties of glass-ceramics.