氧化铝厂赤泥剂的固硫反应动力学特性研究

采用热分析法研究了山东铝业公司赤泥和石灰石固硫反应过程,利用等效粒子模型计算分析了其固硫反应动力学参数,并在此基础上利用压汞仪、SEM分析了赤泥煅烧前后的微观结构,探讨了赤泥固硫机理,为利用氧化铝生产中排放的大量赤泥代替石灰石用作燃煤固硫剂提供了理论依据.结果表明,赤泥的钙利用率是相同条件下石灰石的2～3倍,赤泥煅烧后较石灰石具有更多的中孔和较大的比表面积,可提高化学反应速度和反应深度;另外,赤泥中较多的三氧化二铁和碱金属盐也可提高赤泥固硫反应速率常数和有效扩散系数,但温度过高会降低固体熔点而易导致烧结,削弱其固硫活性.

DESULFURIZATION REACTION MECHANISM AND KINETICS CHARACTERISTIC OF ALUMIUNA PRODUCTION DRAINAGE RED MUD USED FOR COAL DESULFURIZATION AGENTS

From wasted administering waste, sulfation reaction process of red mud and limestone were investigated by thermogravimetic analysis method. The kinetic parameters were calculated and explained according to grain model. And on these basis, calcined sample microstructure are made clear by Mercury Intrusion Porosimeter and SEM respectively. Desulfurization mechanism of red mud is discussed, which provide useful date for red mud as substitute for limestone used for coal desulfurization agents. The result indicated that calcium use ratio of red mud is 2-3 times that of limestone under the same condition, the reasons that red mud achieve good desulphurization effect are that calcined red mud has more middling size hole and bigger specific surface area than calcined limestone, which enlarge desulfurization reaction rate and depth of red mud. Moreover, red mud has more Fe203 and alkali metal salts than limestone, these may enhance the initial reaction rate and product diffusion of sorbent as well. But during high temperature sulfation, they can make a reduction in solid melting point, accelerate sintering and weaken activity of sorbent.