铬酸钠氢还原反应动力学  

Kinetics of hydrogen reduction of sodium chromate

作　　者：尤海侠[1,2] 徐红彬[1] 张懿[1] 李佐虎[1] 郑诗礼[1] 白玉兰[3] 

机构地区：[1]中国科学院过程工程研究所,北京100190 [2]中国科学院研究生院,北京100039 [3]青岛农业大学化学与药学院,山东青岛266109

出　　处：《化工学报》2009年第3期649-653,共5页CIESC Journal

基　　金：国家科技支撑计划项目(2006BAC02A05);国家重点基础研究发展计划项目(2007CB613501);中国科学院知识创新工程优秀青年人才领域前沿项目(082813)~~

摘　　要：The environmental problem resulting from the traditional production process of chromic oxide has spawned public concerns all over the world.Integrated in the clean production technology of chromium compounds with sub-molten salt media,the preparation process of chromic oxide through hydrogen reduction of alkali metal chromate salt enables the clean and short-route preparation of chromic oxide.Moreover,the alkali metal hydroxide byproducts can be recycled as reaction media inside the process.To explore the reaction kinetics and mechanisms of the hydrogen reduction process,the reduction of sodium chromate in H2 atmosphere was investigated by using TGA and DSC techniques.The isothermal TGA measurement results showed that in the temperature range from 703 K to 773 K,the hydrogen reduction had only one step of mass loss and the mass loss rate was from 5.91% to 6.36%.The main products of the reaction were NaCrO2 and NaOH,as confirmed by XRD patterns of the reduction products.The non-isothermal TGA measurements of hydrogen reduction was investigated at six different temperature rising rates of 1,5,10,15,20 and 30 K·min-1.According to the Doyle-Ozawa and Kissinger methods,the activation energy was 342.47 kJ·mol-1 and the order of reduction reaction was 0.87.The results in this work will help to enhance the reaction efficiency and optimize the process flow.The environmental problem resulting from the traditional production process of chromic oxide has spawned public concerns all over the world. Integrated in the clean production technology of chromium compounds with sub-molten salt media, the preparation process of chromic oxide through hydrogen reduction of alkali metal chromate salt enables the clean and short-route preparation of chromic oxide. Moreover, the alkali metal hydroxide byproducts can be recycled as reaction media inside the process. To explore the reaction kinetics and mechanisms of the hydrogen reduction process, the reduction of sodium chromate in H2 atmosphere was investigated by using TGA and DSC techniques. The isothermal TGA measurement results showed that in the temperature range from 703 K to 773 K, the hydrogen reduction had only one step of mass loss and the mass loss rate was from 5.91% to 6.36~. The main products of the reaction were NaCrO2 and NaOH, as confirmed by XRD patterns of the reduction products. The non-isothermal TGA measurements of hydrogen reduction was investigated at six different temperature rising rates of 1, 5, 10, 15, 20 and 30 K · min^-1 .According to the Doyle-Ozawa and Kissinger methods, the activation energy was 342.47 kJ · mol^-1 and the order of reduction reaction was 0.87. The results in this work will help to enhance the reaction efficiency and optimize the process flow.

关 键 词：铬酸钠 氢还原 动力学 

分 类 号：TQ013.2[化学工程]