铅锌硒在镍电解液固体杂质中的形态分析

Speciation analysis of lead,zinc and selenium in solid impurities of nickel electrolyte

镍电解液的品质直接影响电镍的产品质量,镍电解液中除了含有可溶的离子态杂质外,还含有不可溶的固体颗粒杂质。对固体颗粒的性质、形态和来源的研究有助于为镍电解液品质的提高提供理论依据。以固体颗粒中的微量元素铅、锌和硒作为研究对象,分别采用透射电镜、拉曼光谱、傅里叶变换红外光谱和X射线粉末衍射等物理表征方法研究固体颗粒的形态结构;利用Tessier连续提取法对3种微量元素在固体颗粒中的具体形态进行化学剖析。实验表明,该类固体主要由镍、铜、铁、硅的碱式盐、碳酸盐、硫酸盐或复盐形式存在,微量元素铅和锌主要以碳酸盐态和铁/锰态存在,而硒则以可溶态和铁/锰态存在。因此,该类固体颗粒来源于镍电解液的净化段而非来源于同槽工作的阳极液的反扩散。

The quality of nickel electrolyte directly influences the quality of electro-nickel products.Besides of soluble impurities in ionized state,the nickel electrolyte also contains insoluble solid particle impurities.The research of property,speciation and source of solid particles is helpful to provide theoretical foundation for improving the quality of nickel electrolyte.The micro elements in solid particles,including lead,zinc and selenium,were selected as the object of study.The speciation structure of solid particles was investigated by the physical characterization methods such as transmission electron microscopy(TEM),Raman spectroscopy,Fourier transform infrared spectroscopy and X-ray powder diffraction.The detailed speciation of these three trace elements was analyzed using Tessier sequential extraction method.The results showed that the solid particles mainly existed in the form of basic salts,carbonate,sulfate or complex salt of nickel,copper,iron and silicon.Lead and zinc mainly existed in the form of carbonate and iron/manganese oxides,while selenium existed in the form of soluble components and iron/manganese oxides.Therefore,the solid particles were mainly from the purification step of nickel electrolyte rather than the back diffusion of anolyte which stayed in the same bath.