锆酸钙引入形式对MgO-CaZrO_3质弥散型透气材料性能的影响

Effect of adding ways of calcium zirconate on performance of MgO-CaZrO_3 based dispersed porous refractory

为了改善镁质弥散型透气材料的性能,以高纯镁砂颗粒（0.2～1mm）、预合成锆酸钙粉（≤0.074mm）、分析纯碳酸钙粉（≤0.044mm）、分析纯单斜氧化锆粉（≤0.005mm）为原料,设计了最终烧成后均含有87%（w）的高纯镁砂和13%（w）的锆酸钙,但锆酸钙引入形式不同（预合成锆酸钙、利用碳酸钙和氧化锆原位反应生成的锆酸钙、预合成锆酸钙＋原位生成的锆酸钙）的3种MgO-CaZrO3质试样,经配方计算、配料、成型、110℃干燥和1650℃烧成后,检测这3种试样的显气孔率、体积密度、透气度、常温强度、高温强度和抗热震性,并分析其显微结构.结果表明：1）随着原位锆酸钙设计生成量的增加,试样的烧后线收缩率、显气孔率和透气度均增大,常温耐压强度、常温抗折强度、高温抗折强度和抗热震性均呈先增大后减小的变化趋势,锆酸钙的分布也更加均匀;2）综合考虑材料的透气度、常温强度、高温强度和抗热震性,复合引入原位锆酸钙和预合成锆酸钙的试样最佳.

In order to improve the performance of magnesia dispersed porous refractory,high-purity magne-sia particles (0.2 -1 mm),pre-synthesized calcium zirconate powder (≤0.074 mm),analytically pure cal-cium carbonate powder (≤0.044 mm)and monoclinic zirconia powder (≤0.005 mm)were used as start-ing materials to design the formulations based on 87 mass% high purity magnesia and 13 mass% calcium zirconate in the fired specimens.The different calcium carbonate adding ways were adopted:pre-synthe-sized calcium zirconate,in-situ formed calcium zirconate by the reaction between calcium carbonate and zirconia,and pre-synthesized calcium zirconate plus in-situ formed calcium zirconate.After batching,mix-ing,molding,drying at 110 ℃ and firing at 1 650 ℃ for 3 h,the apparent porosity,bulk density,gas permea-bility,thermal shock resistance,cold and hot strengthes,and microstructure of the specimens were investi-gated.The results show:with the increase of the in-situ formed calcium zirconate,the linear shrinkage rate, apparent porosity and gas permeability increase;cold crushing strength,cold modulus of rupture,hot mod-ulus of rupture,and thermal shock resistance increase initially and then decrease;and the distribution of calcium zirconate becomes more uniform.The complex adding of pre-synthesized calcium zirconate and in-situ formed calcium zirconate is optimum for the gas permeability,cold strength,hot strength,and ther-mal shock resistance.