再生镁钙砖抗热震性能的研究

Study on Thermal Shock Resistance of Regenerated MgO-CaO Brick

以AOD炉用后镁钙砖为原料,配以电熔镁砂合成再生镁钙砖。对其抗热震性能进行测试,并测试了热震前后样品的常温抗折强度,然后对比热震前后样品的微观形貌,从而对再生镁钙砖的抗热震性能进行综合评判。结果表明:MgO质量分数为75%的再生镁钙砖热震后外部形貌较热震前无明显变化,热震20次后,其常温抗折强度为35.80 MPa,依旧保持较好的常温力学性能,但是随着热震次数的增加,样品的常温抗折强度逐渐减小,抗折强度损失率逐渐增大,抗热震性系数逐渐减小,且均呈线性变化,主要是因为样品内部由于热应力产生裂纹,并且裂纹逐渐延展扩大所致。

Regenerated MgO-CaO brick samples with MgO contents of 75% were prepared using spent MgO-CaO bricks from AOD furnace and fused magnesite as raw materials. Their room temperature flexural strength and microstructure before and after thermal shock experiments were investigated, and the thermal shock resistance of regenerated MgO-CaO brick was evaluated subsequently. The results showed that there was no obvious change before and after thermal shock experiments for the bulk morphology of regenerated samples. The flexural strength of regenerated samples at room temperature was 35.80 MPa after 20 times thermal shock cycle, which was shown its higher mechanical property at room temperature, however, along with increased the times of thermal shock cycle, the flexural strength at room temperature was lightly decreased, the flexural strength loss ratio was increased, and furthermore lead to the decrease of the thermal shock resistance coefficient, and the linear relationship between the flexural strength and the times of thermal shock cycle were found. Because the internal cracks was generated in the regenerated samples and extended while shocked by the thermal stress, so that the flexural strength at room temperature was gradually decreased.