二氧化硅和氧化铝微粉加入量对MgO基浇注料流变性的影响

Influences of additions of micro-silica and Al_2O_3 ultra fine powder on rheological properties of MgO-based castables

采用电熔镁砂颗粒作骨料,电熔镁砂粉、电熔白刚玉粉、Al2O3微粉和SiO2微粉作基质料,固定骨料与基质料质量比为65:35,且固定基质料中Al2O3微粉与SiO2微粉的总加入量为8%,改变两种微粉的加入比例(Al2O3微粉的加入量分别为8%、6%、4%、2%、0,SiO2微粉的相应为0、2%、4%、6%、8%),分别加6.4%的水制成MgO基浇注料,并采用浇注料流变仪研究了Al2O3微粉与SiO2微粉的加入量对浇注料流变性(扭矩、流动阻力和粘度)的影响。研究结果表明:随着SiO2微粉加入量的增加,浇注料的扭矩、流动阻力和粘度呈降低趋势,但SiO2微粉加入量超过4%后变化很小。

MgO-based castables were prepared by using fused MgO as aggregate; fused MgO fines, fused alumina powder, Al2O3 ultra fine powder and micro silica as matrixes. In the castable's compositions, the mass ratio of aggregate to matrixe was fixed at 65:35, the total addition of micro powders (Al2O3 and SiO2) in matrix maintained at 8% and the ratio of micro powders (Al2O3/SiO2) was changed (the addition of Al2O3 ultra fine powder was 8%, 6%, 4%, 2% and 0 respectively, the corresponding additions of micro silica was 0, 2%, 4%, 6% and 8% respectively), and water addition in the castables was 6.4%. The influences of the additions of Al2O3 ultra fine powder and micro silica on the rheological properties (shear stress, flow resistance and torque viscosity) of the MgO-based castables were studied by using the IBB rheometer V 1.0. The results show that with the increase of micro silica addition, yield stress, shear stress and torque viscosity of the castables tend to decrease, but the increased trend slows down when the addition of microsilica is over 4%.