Designing low-carbon MgO–Al2O3–La2O3–C refractories with balanced performance for ladle furnaces

Abstract

In order to achieve high-quality and stable production of special steel, the performance of low-carbon MgO-C refractories needs to be further optimized. For this purpose, low-carbon MgO–Al2O3–La2O3–C refractories with enhanced thermal shock resistance and slag resistance were designed and successfully prepared by introducing Al2O3 as a reinforcer and La2O3 as a modifier. The results showed that the refractory samples with additives show better overall performance than those without additives. When 10 wt% of Al2O3 and La2O3 were added, the oxidation resistance, thermal shock resistance and slag resistance of the refractory samples coked at 1400 °C are increased by 13.57%, 17.75% and 43.09%, respectively. The analysis found that this can be mainly attributed to the formation of MgAl2O4, Mg2SiO4, and 2CaO·4La2O3·6SiO2 and the consequent volume expansion effect and intergranular phase enhancement effect. Therefore, a low-cost and enforceable reinforcement strategy for low-carbon MgO-C refractories is proposed, which is expected to be applied in steelmaking.