基于水氯镁石合成水合硅酸镁及其在镁质浇注料的应用  

Synthesis of Magnesium Silicate Hydrate Based on Bischofite and Its Application in Magnesia Castables

作　　者：宋绍辉 李亚伟[1,2,3] 廖宁 张思思[1,2] 刘文静[1,2] 李月英[3] 铁生年 SONG Shaohui;LI Yawei;LIAO Ning;ZHANG Sisi;LIU Wenjing;LI Yueying;TIE Shengnian(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China;National-Provincial Joint Engineering Research Center of High Temperature Materials and Lining Technology,Wuhan University of Science and Technology,Wuhan 430081,China;Key Laboratory of Advanced Materials and Applied Technology for Qinghai,Qinghai University,Xining 810016,China)

机构地区：[1]武汉科技大学省部共建耐火材料与冶金国家重点实验室,武汉430081 [2]武汉科技大学高温材料与炉衬技术国家地方联合工程研究中心,武汉430081 [3]青海大学,青海省先进材料与应用技术重点实验室,西宁810016

出　　处：《硅酸盐通报》2023年第2期751-760,共10页Bulletin of the Chinese Ceramic Society

基　　金：青海省自然科学基金面上项目(2022-ZJ-928)。

摘　　要：水氯镁石是一种非常具有应用前景的镁盐资源,其储量丰富,成本低廉。以青海盐湖水氯镁石和水玻璃合成不同MgO/SiO2摩尔比(0.5∶1,1∶1,1.5∶1)的水合硅酸镁(M-S-H)凝胶,采用XRD、SEM、红外和核磁共振等测试手段研究M-S-H的合成机理和结构特征,进而将合成的M-S-H与硅微粉复合制备镁质浇注料,探究M-S-H结构对浇注料结合特性的影响规律。结果表明:不同MgO/SiO2摩尔比的M-S-H呈层状堆叠结构,MgO/SiO2摩尔比为1∶1时M-S-H的层间自由水少,结晶度最高;M-S-H替代部分硅微粉制备镁质浇注料能显著提高1 550℃热处理后浇注料的力学性能,其中MgO/SiO2摩尔比为1∶1的M-S-H复合硅微粉制备的镁质浇注料综合性能最佳,与添加6%(质量分数)硅微粉制备的镁质浇注料相比,其常温抗折强度和高温抗折强度分别提高75%和8%。Bischofite is a very promising magnesium salt resource with abundant reserves and low cost. Magnesium silicate hydrate(M-S-H) gels with different MgO/SiO2molar ratios(0.5 ∶1, 1 ∶1, 1.5 ∶1) were synthesized using bischofite from Qinghai Salt Lake and sodium silicate. The synthesis mechanism and structural characteristics of M-S-H were studied by XRD, SEM, infrared, and nuclear magnetic resonance tests. Then, the synthesized M-S-H was compounded with microsilica to prepare magnesia castable, and the influence of M-S-H structure on the bonding characteristics of castable was explored. The results show that M-S-H obtained from different MgO/SiO2molar ratios exhibits a layered stacking structure. When the MgO/SiO2molar ratio is 1 ∶1, the interlaminar free water is the least and the crystallinity is the highest. The synthesized M-S-H is used to replace part of microsilica to prepare magnesia castable, which significantly improves the mechanical properties of the castable after heat treatment at 1 550 ℃. The magnesia castable prepared with M-S-H(MgO/SiO2molar ratio of 1 ∶1) and microsilica obtains the best comprehensive properties. Compared with the magnesia castable prepared by adding 6%(mass fraction) microsilica, the flexural strength at room temperature and high temperature increases by 75% and 8%, respectively.

关 键 词：水氯镁石 水合硅酸镁 镁质浇注料 抗折强度 微观结构 

分 类 号：TQ175[化学工程—硅酸盐工业]