皮江法炼镁工艺中镁蒸气及杂质冷凝过程热力学分析  

Thermodynamic analysis on condensation process of magnesium vapor and impurities in Pidgeon process

作　　者：钟晶晶 胡磊 李荣斌 张少军 王正[1] 刘风琴 Zhong Jingjing;Hu Lei;Li Rongbin;Zhang Shaojun;Wang Zheng;Liu Fengqin(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Henan Province Industrial Technology Research Institute of Resources and Materials,Zhengzhou University,Zhengzhou 450001,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]郑州大学河南省资源与材料工业技术研究院,河南郑州450001

出　　处：《轻金属》2021年第12期37-41,共5页Light Metals

基　　金：中央高校基本科研业务费专项资金资助项目(2302018FRF-TP-18-095A1);国家重点研发计划(2016YFB-0301101)。

摘　　要：在皮江法炼镁还原过程中,K、Na、Ca、Fe、Mn、Si、Ni、Al等金属杂质会以蒸气形式进入结晶器与镁蒸气共同冷凝,其冷凝行为对结晶器结构设计及结晶镁纯度具有显著影响。基于热力学计算以及理论推断对上述金属杂质的冷凝行为进行分析。结果表明:(1)在皮江法炼镁过程中,球团表面产生的镁蒸气分压为805~3211 Pa,结晶器内镁蒸气饱和蒸气压<2.4 Pa,镁蒸气通过扩散进入结晶器,并且直接由气态冷凝为固态;(2)结晶器内饱和蒸气压较小的金属杂质Ca、Fe、Mn、Si、Ni和Al在靠近挡火板的区域冷凝成固态;饱和蒸气压较大的金属杂质K和Na在靠近罐口的钾钠捕集器上冷凝成液态,Mg在上述两区域之间冷凝;(3)还原区与冷凝区之间的操作条件存在匹配关系,镁蒸气的产出速率及相应冷凝行为因系统压力变化而发生变化,皮江法炼镁实现Mg液态冷凝需保持结晶区温度高于650℃,且系统压力处于350~805 Pa。K, Na, Ca, Fe, Mn, Si, Ni, Al and other metal impurities will enter the crystallizer in the form of vapor and condense with magnesium vapor during the Pidgeon reduction process, which has a significant impact on the crystallizer structure design and the purity of crystallized magnesium. Based on thermodynamic calculation and theoretical deduction, the behavior of those impurities in the condensation process are analyzed in detail. The result show that(1) during the Pidgeon process, the partial pressure of magnesium vapor generated on the surface of the pellets is 805~3211 Pa, the saturated vapor pressure of magnesium vapor in the crystallizer is<2.4 Pa, magnesium vapor diffuses to the crystallizer and condenses directly from gaseous state to solid state;(2) the metal impurities of Ca, Fe, Mn, Si, Ni and Al with lower saturated vapor pressure in the crystallizer condense in solid state in regions near the baffle;the metal impurities of K and Na with higher saturated vapor pressure condense in liquid state on the potassium sodium collector near the tank mouth;Mg condenses between the above two regions;(3) There is a matching operating conditions for the reduction region and the condensation region. Both the output rate of magnesium vapor and the corresponding condensation behavior will change along with the variation of the system pressure. The temperature of the crystallization zone should be kept above 650 ℃ and the pressure should be maintained at 350~805 Pa for the Mg liquid condensation.

关 键 词：皮江法 镁 热力学 金属杂质 

分 类 号：TF822[冶金工程—有色金属冶金]