Al(NO_3)_3对白云石烧结性能和抗水化性能的影响

在天然白云石中添加不同比例的Al(NO_3)_3,采用二步煅烧法制备镁钙砂,研究Al(NO_3)_3添加量对白云石烧结性能和抗水化性能的影响。结果表明,在1 600℃保温3 h,没有添加Al(NO_3)_3时,镁钙砂试样的烧结密度为3.17 g/cm3,显气孔率为4.9%,抗水化增重率为3.1%,粉化率为20.1%,MgO的晶粒尺寸为2.92μm;添加Al(NO_3)_3后,由于Al(NO_3)_3在高温分解产生Al_2O_3,Al_2O_3在高温下会和CaO发生反应,生成3CaO2·Al_2O_3,在高温下形成液相,促进试样烧结,当添加0.30%Al(NO_3)_3(质量分数)时,试样的烧结密度为3.24 g/cm~3,显气孔率为3.8%,抗水化增重率为2.0%,粉化率为15.6%,MgO的晶粒尺寸为3.48μm。

Effect of Al(NO3)3 addition on the sintering properties and hydration resistance of dolomite

The MgO-CaO was prepared by the two-step calcination method through adding Al(NO3)3 in natural do-lomite. The effects of Al(NO3)3 addition on the sintering properties and hydration resistance of dolomite were stud-ied. Results show that,the MgO-CaO sample has the sintered density of 3.17 g/cm3,apparent porosity of 4.9％, hydration resistance weight gain rate of 3.1％,pulverization rate of 20.1％,and the MgO grain size of 2.92μm when sintered at 1600℃for 3 h. The Al(NO3)3 decomposes into Al2O3,and Al2O3 reacts with CaO to form 3CaO2· Al2O3 at high temperature,thus the liquid phase forms during sintering,and promoting the sintering process of the samples. When adding 0.30％Al(NO3)3(mass percent),the MgO-CaO sample has the sintered density of 3.24 g/cm3, apparent porosity of 3.8％,hydration resistance weight gain rate of 2.0％,pulverization rate of 15.6％,and the MgO grain size of 3.48μm when sintered at 1600℃for 3 h.