中文摘要：

焦煤的热解经历干燥阶段、胶质体阶段和焦炭生成三个阶段,第二阶段焦煤失重较多。常压条件下焦煤热解时固定炭损失较多,孔隙度随温度和时间的增加而增加,500℃热解30 min后胶质体数量较少,物料内部变化不大;真空条件下煤热解时固定炭不损失,孔隙度随温度的升高而降低,且随着时间的延长升高,60 min后降低,500℃热解30 min可生成较多数量的胶质体,碳元素和镁元素分布趋于均匀。用焦煤做还原剂进行氧化镁真空碳热还原可以得到较纯净的金属镁,没有发生喷料现象。焦煤具有良好的黏结性和结焦性,适于做还原剂。

英文摘要：

The pyrolysis of coal-coke in carbothermic reduction of magnesia in vacuum was studied.Three distinctive stages were identified,including high temperature drying or water evaporation,colloid formation,and coke formation.In the second stage,when heated at a 500℃,the content of the fixed carbon in coal-coke remained unchanged,in contrast to the pyrolysis of coal-coke in air at 500℃ for 30 min,where a great deal of fixed carbon gets lost,and little colloid is formed.Moreover,in vacuum pyrolysis,the porosity decreases with an increase of temperature,and it also increases with heating time till 60 min.The pyrolysis of coal-coke at 500℃ for 30 min resulted in a large amount of colloid,containing uniformly mixed carbon and magnesium.The results show that high quality metal Mg can be produced by carbothermic reduction of magnesia in vacuum with coal-coke as the reduction agent,and that no spraying of raw materials was observed.