煅烧制度对MgO活性的影响

Effects of calcined conditions on activity of MgO

以菱镁矿为原料，煅烧温度800-1200℃，保温时间分别为30、60和90min制备M护．应用X射线衍射分析不同煅烧温度、不同保温时间对MgO的影响，柠檬酸法测定MgO的活性，谢乐公式等计算MgO的晶粒尺寸．讨论了煅烧温度、保温时间、晶粒尺寸与MgO活性之间的关系．结果表明：煅烧温度在950℃以上时，任何保温时间的MgCO3均已完全分解．煅烧温度越高，保温时间越长，MgO的活性越差；晶粒尺寸越大，MgO的活性越差．

Magnesite was used to prepare MgO. Its calcining temperature is at 800 - 1 200℃ and soaking time is 30 min, 60 min, and 90 rain, respectively. The effects of different calcination temperatures and soaking time on MgO were studied by X-ray diffraction（XBD）. The activity of MgO was evaluated by the citric acid method. The grain size of MgO was calculated according to the Scherrer formula. Relations among calcination temperature, holding time, grain size, and the activity of MgO were discussed. As a result, MgCO3 was decomposed at any holding time, when calcination temperature was higher than 950 ℃. The result showed that the the worse the activity of MgO was, the bigger the grain higher the calcination temperature, the longer the holding time, size, the worse the activity of MgO was.