热处理时间对透辉石系尾矿微晶玻璃析晶及其性能的影响

Influences of Heat Treatment Soaking Time on Crystallization and Properties of Tailings-based Glass-Ceramics

使用金尾矿和铁尾矿为主要原料,采用熔融法和一步法析晶热处理制备了透辉石系尾矿微晶玻璃。将其分别在低温段720℃和高温段820℃保温,使用DSC、XRD、Raman光谱、SEM和综合力学性能仪等手段研究了保温时间对透辉石系尾矿微晶玻璃析晶过程及性能的影响。结果表明:该系微晶玻璃的主晶相为单斜结构的透辉石晶体(Mg0.6Fe0.2Al0.2)Ca(Si1.5Al0.5)O6(JCPDS 72-1379),晶体的生长过程包括玻璃的分相、成核和晶体生长过程。热处理温度为低温段720℃时透辉石晶体的成核温度为720℃,随着保温时间的延长透辉石晶体逐渐长大且由球状晶向枝状晶演变,透灰石晶体的析出量逐渐增加;热处理温度为高温段820℃时透辉石晶体的形貌均为尺寸较大的枝状晶,但是随着保温时间的延长透辉石晶体的形貌和尺寸变化不大。综合性能最优的热处理制度为在820℃保温45 min,制备出的微晶玻璃密度为2.97 g/cm3,抗折强度为211.0 MPa,硬度为789.0 MPa,耐酸性99.3%,耐碱性99.1%。

Diopside tailings-based glass-ceramics were prepared via melting method plus one-step crystallization heat treatment with Shandong gold tailings and Guyang iron tailings as the main raw material.Then the influence of heat treatment soaking time on the crystal growth and properties of the prepared glass-ceramics was investigated by DSC,XRD,Raman spectroscopy,SEM,and universal mechanical properties tester.The results show that diopside crystals can grow through nucleation and whereafter growth when heat treated at 720℃for 30 min.With the increase of heat treatment time,the size of diopside crystals gradually increased and the morphology of the crystals evolved from spherical to dendritic.When the heat treatment temperature was 820℃,the morphology and structure of the diopside crystals did not change with the increase of soaking time.Thus,heat treatment at 820℃for 2 h can be considered to be the optimal.The prepared glass ceramics exhibit an excellent comprehensive performance with density of 2.97 g/cm3,bending strength of 211.0 MPa,hardness of 789.0 MPa,acid resistance of99.4%and alkali resistance of 99.3%respectively.