Direct electrolytic preparation of chromium metal in CaCl_2-NaCl eutectic salt  

在CaCl_2-NaCl共融盐中直接电解制备金属铬（英文）

作　　者：刘政伟 张红玲[1,2] 裴丽丽[1,2] 石义朗 蔡再华[4] 徐红彬 张懿 

机构地区：[1]中国科学院绿色过程与工程重点实验室(中国科学院过程研究所),北京100190 [2]中国科学院过程工程研究所湿法冶金清洁生产技术国家工程实验室,北京100190 [3]中国科学院大学,北京100049 [4]湖北振华化学股份有限公司,黄石435001

出　　处：《Transactions of Nonferrous Metals Society of China》2018年第2期376-384,共9页中国有色金属学报（英文版）

基　　金：Project(2013CB632600)supported by the National Basic Research Program of China;Projects(21376251,21406233)supported by the National Natural Science Foundation of China;Project supported by the Fund of Hubei Zhenhua Chemical Co.,Ltd.,China

摘　　要：The electro-reduction of chromium oxide（Cr2O3） was investigated in an equimolar mixture of CaCl2-NaCl molten salt at 800℃ for developing a more efficient process for chromium preparation. Cyclic voltammetry and potentiostatic electrolysis were used to study the electro-reduction of the Cr2O3-loaded metallic cavity electrode. In addition, a number of parameters affecting the rate and extent of Cr2O3 electrolysis were considered to better understand the electrolysis process. The results demonstrate that CaCl2-NaCl molten salt is applicable for preparing Cr directly from Cr2O3 and the electrolysis parameters exert great influence on the cathode product. Under optimal experimental conditions, nodular Cr with an oxygen content of 0.5%（mass fraction） was obtained without any chromium carbides detected by XRD. Furthermore, the relatively high solubility of CaO and quite rapid crystal growth result in the formation of large platelet CaCr2O4, and the addition of NaCl to CaCl2 results in several variations on the electrolysis process and the product morphology from pure CaCl2 molten salt.通过考察800°C下固体三氧化二铬(Cr_2O_3)在等摩尔CaCl_2-NaCl熔盐中的电还原过程,得到一个更高效的金属铬制备工艺。利用循环伏安和恒电势电解法考察负载Cr_2O_3的金属空洞电极的电还原过程,并考察影响Cr_2O_3电解速率和电解程度的重要电解参数。结果表明:CaCl_2-NaCl熔盐可用作直接电解Cr_2O_3制备金属铬的熔盐;电解参数对电解产品质量影响明显。在最佳电解条件下,得到氧含量为0.5%(质量分数)的节支状金属铬产品,且X射线衍射法没有检测到任何碳化铬存在。此外,CaO较高的溶解度和CaCr_2O_4较快的晶体生长速率导致大颗粒片状CaCr_2O_4的生成。与纯CaCl_4相比,在CaCl_2中添加NaCl可明显改变电解过程和产物形貌。

关 键 词：ELECTROLYSIS CHROMIUM chromium oxide CaCl2-NaCl molten salt 

分 类 号：TF791[冶金工程—钢铁冶金]