钙硅比对稳定镁白云石材料性能的影响

Effect of calcia/silica ratio on properties of stabilized magnesia dolomite materials

以白云石、菱镁矿和硅石为初始原料,采用消化、二步煅烧工艺,制备稳定镁白云石合成料;在此基础上,制备了不同钙硅比(CaO、SiO_(2)质量比分别为2.6、2.8、3.0)的烧成稳定镁白云石试样,研究了钙硅比对稳定镁白云石材料性能的影响。结果表明:随着钙硅质量比的增大,试样的体积密度降低,抗热震性逐渐提高,但试样的水化质量增加率略有升高。降低钙硅比会影响镁钙材料的挂窑皮性能,主要是由于钙硅比较高时试样内有少量f-CaO存在,可以与水泥熟料反应从而提高粘接强度。因此,为满足该镁白云石材料在具有优异高温性能的同时,能够显著提高其抗水化性,选择最佳钙硅质量比为2.8。

The stabilized magnesia dolomite sands were prepared using dolomite,magnesite and silica as the starting materials,digesting and two-step calcining.Sintered stabilized magnesia dolomite specimens with different calcia/silica mass ratios(2.6,2.8 and 3.0,respectively)were further prepared.Effects of the calcia/silica ratios on properties of the stabilized magnesia dolomite materials were investigated.The results show that with the increase of the calcia/silica ratio,the bulk density of the specimens gradually decreases,the thermal shock resistance gradually increases,the hydration mass gain rate slightly increases.Reducing the calcia/silica ratio affects the coating adhesion performance of magnesia-calcia materials,mainly due to the presence of a small amount of f-CaO in the specimen when the calcia/silica ratio is high,which can react with cement clinker and thus enhance the bonding strength.In order to satisfy the magnesia dolomite material with excellent high temperature performance and obviously enhanced hydration resistance,the optimal calcia/silica ratio of 2.8 is selected.