球团预制-硅热还原炼镁还原罐内传热

为了解决皮江法还原罐内传热慢的问题,提出将白云石粉、硅铁、萤石混合,加入黏结剂先造球再煅烧,煅烧后的热球团直接用于还原的炼镁新技术.采用数值方法研究预制球团在还原罐内的传热规律.结果表明:提高硅铁添加量、增加球团直径、减小床层密度均有利于热量向还原罐内部传递;将边界温度由1473K提高至1498K,还原罐中心区域达到1473K的时间由300min缩短至178min;当还原罐直径为300mm时,对于直径为25mm的预制球团,还原罐中心点加热至1473K的时间为90min,而对于皮江法球团则需要288min.

Heat Transfer in a Retort for Mg-Extraction by Pre-prepared Pellet Silicothermic Process

A novel method of feed preparation for silicothermic process was proposed in order to solve low efficiency of heat transfer in Pidgeon process. In this method, dolomite and ferrosilicon were mixed to produce pellets and then were calcined. The pre-prepared pellets were charged into the retorts for Mg extraction at once after calcinations. Heat transfer in a retort for the novel process was investigated by a numerical method. The results show that a better heat transfer can be obtained by increasing the amount of Si-Fe addition, pellet diameter or decreasing the packed bed density. The time for heating the center of the retort into 1473K decreases from 300min to 178min, after increasing the boundary temperature from 1473K to 1498K. In a retort of 300mm diameter, the heating time is 90min for the center of the retort charged by pre-prepared pellets of 25mm diameter reaching 1473K, compared with that of 288min in Pidgeon process.