【作者】 尹洪峰； 马艳龙； 李波涛；

【Author】 Yin Hongfeng,Ma Yanlong,Li Botao (School of materials science and engineering Xi’an University of architecture and technology,Xi’an 710055)

【机构】 西安建筑科技大学材料科学与工程学院；

【摘要】 为了提高MgO-CaO材料的抗水化性能,采用碳热还原输运氧化法在MgO.-CaO砂上沉积MgO涂层。借助X射线衍射仪和扫描电子显微镜等手段研究了碳还原剂类型、沉积温度、保温时间和氧气流量对两种MgO-CaO砂(CaO含量分别为22%和55%)涂覆后抗水化性能的影响,结果表明:(1)炭黑与石墨和焦碳相比,由于粒度细、反应活性高,其作为还原剂效果优于其他两者;(2)在1450～1600℃范围内,随着沉积温度升高,处理后镁钙砂的抗水化性能提高;(3)随MgO涂层沉积时间的延长抗水化性提高,但超过4h后,沉积生成氧化镁达到一定厚度,镁钙砂的抗水化性能不再变化;(4)氧气流量对涂覆后MgO-CaO砂抗水化性能影响不大,说明氧气供给不是涂层沉积的限制阶段;(5)用碳黑作为还原剂,氧气流量为250 L/h,在1600℃下沉积MgO涂层4h。涂覆后CaO含量为22%镁钙砂水化增重率0.09%,粉化率0.12%;CaO含量为55%镁钙砂水化增重率0.10%,粉化率1.16%。更多还原

【Abstract】 In order to improve the hydration resistance of MgO-CaO clinker MgO coating was fabricated by carbothermal reduction of MgO with carbon as reduction agent,transportation of Mg steam and then the oxidation of Mg steam.Effect of carbon reduction agent,deposition reaction temperature,holding time and O₂ flow on the hydration resistance of treated MgO-CaO clinkers（CaO content were of 22%and 55%respectively）were investigated by XRD and SEM.The results indicated that:（1）carbon black was easier to react with MgO than graphite and coke due to its finer particle size and higher reactive activity so the hydration resistance of treated MgO-CaO clinkers was best when carbon black was used as reduction agent.（2）The higher the reaction temperature was,the better the hydration resistance of treated MgO-CaO clinker was when reaction temperature was among 1450～1600℃.（3）The hydration resistance of treated MgO-CaO clinker increased as the holding time was prolonged.But when the holding time was above 4 hours the hydration resistance wouldn’t increase.（4）O₂ flow had little influence on experimental result when O₂ flow was 2501/h and 5001/h respectively.Those demonstrate that the transportation of oxygen is not the controlling step during the deposition process of MgO coating.（5）When carbon black was used as reduction agent,O₂ flow was of 250l/h,MgO-CaO clinkers were coated at 1600℃for 4h,the weight gain percent and pulverization percent of MgO-CaO clinker with 22%CaO were of 0.09%and 0.12%respectively.They were 0.10%and 1.66%for MgO-CaO clinker with 55%CaO.更多还原