【摘要】 将分析纯CaO、MgO、LaCrO3分别粉磨至粒度≤74μm,CaO与MgO按质量比1 1混合,然后分别外加质量分数为0.6%、0.8%、1%、1.5%、2%、3%的LaCrO3,再分别于1 500、1 530和1 550℃保温3 h煅烧制成CaO质量分数为50%的合成MgO-CaO(镁钙)质耐火材料。通过对试样水化质量增加率的测定并结合XRD、SEM和EDS分析,研究了LaCrO3对合成镁钙质材料抗水化性能和结晶特性的影响。结果表明:LaCrO3加入质量分数≤1%时可以明显提高MgO-CaO材料的抗水化性,煅烧温度为1 550℃时,水化质量增加率最低,仅为0.183%。LaCrO3对MgO-CaO材料中CaO晶粒的生长有促进作用,而对MgO晶粒的生长促进影响甚微;Cr2O3与CaO在高温下生成了CaO.Cr2O3,能够促进烧结,同时包裹在CaO晶粒表面进一步减少了CaO与水接触的机会,从而提高了镁钙质耐火材料的抗水化性能。更多还原

【Abstract】 Analytically pure CaO,MgO,and LaCrO3 were ground to smaller than 74 μm.MgO-CaO refractories with 50% CaO were prepared by mixing CaO and MgO according to 1:1 of mass ratio,extra-adding different amounts of LaCrO3(0.6%,0.8%,1%,1.5%,2%,and 3%),and firing at 1 500,1 530,and 1 550 ℃ for 3 h,respectively.Effect of LaCrO3 on hydration resistance and crystallization property of MgO-CaO refractories was researched by determining hydration mass gain and by means of XRD,SEM,and EDS.The results show that:(1)≤1% LaCrO3 can significantly improve the hydration resistance of MgO-CaO refractories.When it is fired at 1 550 ℃,the hydration mass gain is the lowest 0.183%;(2)LaCrO3 can promote the growth of the CaO grain,while it has little effect on MgO grain;(3)Cr2O3 reacts with CaO forming CaO·Cr2O3 which can promote sintering,and wraps CaO grain to reduce the contact with water further and to improve the hydration resistance of MgO-CaO refractories.更多还原