Al_(2)O_(3)对钙硅镁系微晶玻璃性能和析晶动力学的影响

Effect of Al_(2)O_(3) on properties and crystallization kinetics of calcium-silicon-magnesium glass-ceramics

冶金渣经过改质还原并回收金属铁元素后,利用剩余熔渣直接制备成微晶玻璃等高附加值材料,是实现冶金渣高效低碳资源化的有效途径之一。提取金属铁后的熔渣多以CaO-SiO_(2)-MgO渣系为主,通常还需要补充适量Al_(2)O_(3)来改善微晶玻璃相关性能。本文通过向CaO-SiO_(2)-MgO三元玻璃体系中引入不同比例Al_(2)O_(3),来研究其对微晶玻璃抗弯强度和析晶动力学的影响。结果显示,微晶玻璃抗弯强度主要受烧结收缩率影响,在Al_(2)O_(3)为15%时,以钙长石为主晶相的微晶玻璃抗弯强度达到最大值;随着Al_(2)O_(3)含量增加,玻璃固相开始熔化温度T_(s)和液相开始析晶温度T_(l)逐渐降低,析晶峰温度T_(c)和析晶活化能E_(c)逐渐升高,而析晶速率常数k(T_(c))和晶化指数n没有明显变化。研究结果说明,随着Al_(2)O_(3)含量的增加,玻璃烧结阻力降低,析晶阻力增加。

The metallurgical slag is modified and reduced to recover iron metal,and then directly prepared into high-value building materials like glass-ceramics,which is one of the effective ways to realize high efficiency and low carbon recycling of metallurgical slag.The slag after metal extraction is mainly the CaO-SiO_(2)-MgO system(CSM),and it is usually necessary to supplement an appropriate amount of Al_(2)O_(3)to improve the related properties of glass-ceramics.In this paper,by controlling the Al_(2)O_(3)content of the CSM ternary glass system,the effects of corresponding parent glass on the flexural strength and crystallization kinetics of glass-ceramics were studied.The results show that the flexural strength of glass-ceramics is mainly affected by the sintering shrinkage.When Al_(2)O_(3)is 15%,the flexural strength of glass-ceramics with anorthite as the main crystal phase reaches the maximum.With the increase of Al_(2)O_(3)content,the T_(s) and T_(l) decrease,the T_(c) and E_(c) gradually increase,while the k(T_(c))and n value do not change significantly.It shows that the sintering resistance of glass is decreasing,but the crystallization resistance is increasing.The original dominant crystal structure is affected while Al_(2)O_(3)>12%,with the anorthite crystal phase appearing consequently.When the weight content of Al_(2)O_(3)is 15%,both the flexural strength and the shrinkage rate reached the maximum,and dense microstructure as well as higher values of T_(c),E_(c) and k(T_(c))were obtained.The research results show that with the increase of Al_(2)O_(3)content,the glass sintering resistance decreases and the crystallization resistance increases.