氯氧镁水泥及其对镁质浇注料力学性能的影响

Magnesium oxychloride cement and its effect on mechanical properties of magnesia based castable

采用XRD和TG -DSC分析方法研究了氯氧镁水泥的相组成和加热相变化 ,并研究了氯氧镁水泥结合剂对镁质浇注料热处理后常温抗折强度的影响。结果表明 :采用电熔镁砂和MgCl2 ·6H2 O为原料生成的氯氧镁水泥 ,是由氯氧镁凝胶和少量的5Mg(OH) 2 ·MgCl2 ·8H2 O(简称 5·1·8)晶相组成的 ;加热时经过脱水反应和分解反应 ,5 0 0℃以后氯氧镁水泥的分解反应完成 ;所生成的氯氧镁水泥能明显提高镁质浇注料的烘干抗折强度 ,但生成过多的氯氧镁水泥时 ,其在烧成过程中的分解反应又会引起材料烧后 (16 0 0℃ 3h)抗折强度的降低 ,故材料中MgCl2 ·6H2 O的最佳加入量为 2 % (质量分数 )

The phase compositions and heating changes of magnesium oxychloride cement were studied by XRD and TG-DSC analysis and effect of magnesium oxychloride cement on mechanical properties of magnesia based castable was investigated.The experimental results show that magnesium oxychloride cement prepared with fused magnesia and MgCl 2·6H 2O consists of magnesium oxychloride gel and 5Mg(OH) 2·MgCl 2·8H 2O(5·1·8)crystal phase;Magnesium oxychloride cement decomposes fully by dehydration and decomposition reaction at 500 ℃.Magnesium oxychloride cement can improve the MOR(110 ℃ 24 h) of magnesia based castable apparently,whereas decrease the MOR(1600 ℃ 3 h) due to decomposition reaction when magnesium oxychloride cement is excessive.The optimum content of MgCl 2·6H 2O in magnesia based castable is 2wt%.