以托帕石为原料的莫来石耐火骨料的制备及其烧结机理  

Preparation and Sintering Mechanism of Mullite Refractory Aggregates Derived from Topaz

作　　者：朱伯铨[1] 魏国平[1] 李享成[1] 马铮 

机构地区：[1]武汉科技大学耐火材料与高温陶瓷国家重点实验室培育基地,武汉430081 [2]浙江自立股份有限公司,浙江上虞312300

出　　处：《硅酸盐学报》2014年第3期377-383,共7页Journal of The Chinese Ceramic Society

基　　金：国家"973"计划(2012CB722702);国家自然科学基金(51374162);武汉市晨光计划(201271031379)资助

摘　　要：以澳大利亚托帕石精矿为原料，经湿法球磨、烘干后以150MPa压力压制成Ф20×20mm的试样，再分别经1300、1400、1500、1600、1700和l750℃煅烧3h，通过测试试样煅烧后的线变化率、显气孔率、体积密度、吸水率和常温耐压强度，研究了煅烧温度对试样烧结性能的影响，分析了烧结机理。结果表明，试样经1300℃煅烧3h后，托帕石完全转化为柱状莫来石晶须。随煅烧温度升高，莫来石晶须逐渐烧结；试样经1750℃煅烧3h后，显气孔率为1．4％，体积密度为2．89g／cm3，常温耐压强度为648MPa。烧结机理分析表明：试样在1300～1500℃为固相烧结，烧结传质方式为体积扩散；当煅烧温度高于1600℃时，试样中生成少量的液相，液相的存在起到烧结助剂作用，使试样致密化过程明显加快，晶粒尺寸显著增大。The specimens were prepared with a topaz concentrate from Australia as raw materials. The topaz concentrate was wet ball-ground, dried, and pressed into the specimens of Ф 20 × 20 mm under 150 MPa. Then the specimens were calcined at 1 300, 1 400, 1 500,1 600, 1 700 and 1 750 ℃ for 3 h, respectively. The apparent porosity, bulk density, water absorption, permanent linear changes and compression strength of the specimens were determined. The effect of calcination temperature on the sintering behavior of the specimens was investigated, and the sintering mechanism was analyzed. The results show that the topaz will be translated into columnar mullite completely after calcination at ] 300 ℃ for 3 h. Mullite whiskers are sintered gradually when the calcination temperature increases. After calcined at 1 750 ℃/or 3 h, the specimens with an apparent porosi- ty of 1.4% and a bulk density of 2.89 g/cm3 can be obtained. The corresponding compression strength reaches 648 MPa. The analysis of sintering mechanism suggested that the sintering process of the specimens calcination at 1 300-1 500 ℃ belongs to solid state sintering, which is controlled by volume diffusion. When the sintering temperature is above 1 600 ℃, small amount of liquid phase formed in specimen could be served as sintering aids, which can speed up the densification process and increase the grain size remarkably.

关 键 词：托帕石 莫来石 耐火骨料 烧结机理 

分 类 号：TQ175.1[化学工程—硅酸盐工业]