锆英石添加剂对白云石矿物性能和显微结构的影响

Effect of zircon additives on the microstructure and properties of dolomite

通过研究锆英石添加剂对白云石显微结构的影响,发现了ZrO2、SiO2与MgO、CaO的结合方式及特性。结果表明,锆英石对白云石矿物耐压强度有降低作用;热震实验温度为1100℃、锆英石加入量为4%时,白云石矿物抗折强度损失率最小;显微结构研究发现,加入锆英石后,白云石矿物的方镁石晶粒发育较大,并随着CaZrO3的生成伴有体积膨胀,围绕CaZrO3颗粒产生放射状微裂纹,这些微裂纹的存在,增加了耗能机制,阻止裂纹扩展,而使试样的热震稳定性能提高;同时,锆英石的引入使白云石矿物抗水化性能得到改善,当加入4%的锆英石时水化增重率最小。

The effect of zircon additive on the microstructure of calcia- rich magnesia-calcia materials, the bonding way and properties of ZrO2 and SiO2 with MgO and CaO have been studied . The results are as follows： The crushing strength of specimens decreases after adding zircon; The effects of the different additions of zircon on the loss rate of MOR （modulus of rupture ） of the material are quite different when the thermal shock temperature is 1100℃. The loss rate of MOR of specimens is the lowest when the addition of zircon is 4% ; The crystal size of MgO in matrix to which zircon is added, is bigger than that of the specimen without zircon addition. With the formation of CaZrO3, the specimen has the expansion in volume. SEM observations found that there were radial microcracks around CZ （CaZrO3） grains. It is the existence of these kinds of microcracks that increase the mechanism of consuming energy which hamper the propagation of cracks and hence the thermal shock stability is higher, The property of hydration resistance is improved by zircon addition and the best amount of which is 4 %.