不同轻质骨料对高铝浇注料性能的影响

Effects of different light-weight aggregates on properties of high alumina castables

为了提高轻质高铝浇注料的中高温强度,降低加热永久线变化,研究了体积密度分别为1.54、1.42g.cm-3的2种轻质高强微孔矾土骨料以及体积密度为1.53 g.cm-3的普通轻质高铝骨料对轻质浇注料110℃24 h烘干、1 000℃3 h和1 400℃3 h烧后性能的影响。结果表明:110℃24 h烘干后,利用体积密度为1.54 g.cm-3的微孔轻质骨料和1.53 g.cm-3的普通轻质高铝骨料所制备的浇注料的体积密度均为1.80g.cm-3左右,轻质骨料体积密度越低,利用其所制备的浇注料体积密度越低,显气孔率越高;轻质骨料内部孔径微小化,可明显提高轻质浇注料各温度处理后的常温耐压强度和常温抗折强度,降低轻质浇注料的加热永久线变化;由于微孔骨料内显气孔率较高,利用其制备的轻质浇注料500℃低温下热导率比普通轻质高铝骨料的高,但在1 000℃下相差不大,均在0.42 W.m-1.K-1左右。由此可见,轻质高铝骨料内部孔径微小化和Al2O3含量的提高使轻质浇注料的性能更优。

Effects of two micropore high strength light-weight bauxite aggregates （BD 1.54 and 1.42 g· cm-3） and a common light-weight high alumina aggregate （BD 1.53 g · cm-3） on properties of light- weight castables treated at 110℃ for 24 h,1 000℃ for 3 h and 1400℃ for 3 h,respectively,were studied in order to improve the medium and high temperature strengths and decrease the permanent change in dimensions on heating. The results show that the bulk densities of the castables prepared with the micropore aggregate （BD is 1.54 g · cm-3） and the common aggregate （BD is 1.53 g · cm-3） are all around 1.80 g · cm-3. The lower the bulk density of the aggregate,the lower the bulk density and the higher the apparent porosity of the castables. Aperture miniaturization of the added aggregate can increase the cold crushing strength and cold modulus of rupture of the light-weight castables after treated at different temperatures, decrease the permanent change in dimensions on heating. Due to the high apparent porosity of the micropore aggregate,the prepared light-weight castables have higher thermal conductivity at 500 ℃ than those prepared by common aggregate,but at 1000 ℃,they are approximate,about 0.42 W · m^-1 · K^-1 Thus,the miniaturization of internal aperture and the increasing of the Al2O3 content can improve the performance of light-weight castables.