自流浇注料的研究与开发

自流浇注料是一种无需振动即可浇注成型的浇注料,随着钢铁冶炼技术的发展,自流浇注料的应用也在不断拓展,它不仅能用于座砖与包底砖的接缝处,而且还可用于钢包壁和包底、中间包永久层、电炉三角区、高炉出铁沟、CAS-OB炉、加热炉等。本文从原材料的选用、级配、超微粉技术的引入、高效有机添加剂等,通过复相改性手段对自流浇注料进行了研究与开发。     

Structure and properties of lightweight magnesia refractory castables with porous matrix

To improve the energy-saving capacity of magnesia refractory castables for working lining of high-temperature kilns, this study presents the researches on microstructure and properties of lightweight magnesia refractory castables with porous matrix fabricated by direct foaming method. The results show that formation of closed-pores in the matrix significantly enhanced high-temperature thermal insulation performance of castables with minor changes of slag corrosion resistance. The thermal conductivity of the lightweight magnesia castables at 1000 °C was below 1.2 W/m·K, which is 47.8% lower than that of the referenced magnesia castable. The increasing content of SDS (foaming agent, over 0.02 wt%) led to increments of size and number of large-sized pores, resulting in the significantly decreased density and mechanical performances. The slag resistance mechanism reveals that, in addition to intergranular penetration, the accumulation of slag and penetration between adjacent pores were the major ways of slag mass transfer in lightweight magnesia castables. In conclusion, controlling the size (below 53.2 μm), number and distribution of closed-pores in the matrix is effective to realize the coupling of high thermal insulation, mechanical properties and slag resistance for lightweight magnesia castables used in the metallurgical field.     

Effects of different additives on properties of magnesium aluminate Spinel–Periclase castable

Bauxite- and alumina-based spinels were employed as refractory aggregates, and sintered magnesia fine powder, calcium aluminate cement, microsilica, and activated α-Al₂O₃ were utilized as matrices. The effects of alumina powder, analytically pure zinc oxide, and analytically pure zirconia on the properties of magnesium aluminate spinel–periclase castables were studied. The results demonstrated that the addition of the three additives promoted the sintering of magnesium aluminate spinel–periclase castables. Simultaneously, the three additives significantly improved the high-temperature properties of the samples. The thermal shock resistance of the alumina powder sample increased by 200%, that of the pristine zinc oxide sample by 75%, and that of the zirconia sample by 125%. The additives effectively improved the thermal shock resistance of the magnesium aluminate spinel–periclase castable. In addition, the slag resistance depths of the samples with alumina powder and zirconia were 41% lower than that of the sample without additives, which significantly improved the slag resistance of the magnesium aluminate spinel–periclase castable.     

富氧对高炉送风管用浇注料的性能与结构的影响

在实验室条件下,分析了不同通氧速率对高炉送风管用浇注料的性能与结构的影响。研究结果表明:通氧速率增加,抗压强度有所提高;1 200℃烧后体积密度从2.73g/cm3降到2.66g/cm3,气孔率由17.59%增加到19.47%;由于气孔增加,导热加快,在风管内衬比较薄的情况下,容易导致风管管壳发红;采用涂覆涂料封闭气孔的方法可以降低浇注料的传热,使风管的表面温度处于安全范围内。