Abstract:

In order to improve the service life,the MgO-C brick specimens were prepared using the fused magnesia (5-3,3-1,≤1 mm and ≤0.074 mm),flake graphite (≤0.15 mm),Si powder (≤0.044 mm),Al powder (≤0.044 mm) and calcium hexaluminate (≤0.044 mm) as raw materials and the thermosetting phenolic resin (PF5323) as the binder,mechanical pressing under 150 MPa,then carbon embedded firing at 1 200 and 1 400 ℃ for 3 h,respectively.Effects of calcium hexaluminate additions (0,3%,6%,and 9%,by mass) on the properties of MgO-C refractories were researched.The results show that:as the addition of calcium hexaluminate is 3%,the specimen performs the best cold physical properties and slag corrosion resistance.The addition of calcium hexaluminate can accelerate the sintering among particles at high temperatures,forming magnesium aluminate spinel in the refractories,improving the MOR and the crushing strength.Meanwhile,Al₂O₃ is formed,which increases the viscosity of liquid molten slag,improving the corrosion resistance of MgO-C refractories.

Key words: calcium hexaluminate, magnesia-carbon refractories, slag corrosion resistance

摘要：

为提高MgO-C耐火材料的寿命,以电熔镁砂(5~3、3~1、≤1、≤0.074 mm)、鳞片石墨(≤0.15 mm)、Si粉(≤0.044 mm)、Al粉(≤0.044 mm)、六铝酸钙(≤0.044 mm)为原料,以热固性酚醛树脂为结合剂,以 150 MPa 压力机压成型制备了MgO-C砖试样。试样经过1 200、1 400 ℃保温3 h埋碳处理,研究了六铝酸钙加入量(质量分数分别为0、3%、6%、9%)对MgO-C耐火材料性能的影响。结果表明:六铝酸钙加入量(w)为3%时,试样的常温物理性能和抗渣侵蚀性能最好。六铝酸钙的加入能促进高温下颗粒间的烧结反应,在耐火材料内部生成镁铝尖晶石,有利于提升材料的抗折强度和耐压强度;与熔渣反应生成复合尖晶石的同时,释放出Al₂O₃,增加液相熔渣的黏度,提高MgO-C耐火材料的抗侵蚀性能。

关键词: 六铝酸钙, MgO-C耐火材料, 抗渣侵蚀性