低温电解质熔体中NiFe_2O_4基惰性阳极电解腐蚀初探

通过电解前后阳极的外观形貌、微观形貌及槽电压,研究不同槽型对电解腐蚀的影响,并以优化后的电解槽研究5Cu/(NiFe2O4-10NiO)金属陶瓷惰性阳极在Na3AlF6-K3AlF6-AlF3-Al2O3电解质中的电解腐蚀。结果表明:电解后阳极存在一定程度的腐蚀,且少量电解质已渗透到阳极中。     

用于铝电解的贵金属陶瓷复合涂层惰性阳极及其制备方法

用于铝电解的贵金属陶瓷复合涂层惰性阳极及其制备方法,涉及有色金属熔盐电解领域以及金属陶瓷复合材料制备技术。该惰性阳极由合金基体、合金表面的氧化物薄膜和外层的贵金属一氧化铝复合层构成,贵金属一氧化铝复合层具有贵金属包覆氧化铝颗粒的结构。这种贵金属陶瓷复合涂层惰性阳极具有贵金属的理想惰性阳极特性,在铝电解过程中电极表面仅发生析出氧气的反应,     

阳极电流密度对NiFe2O4基惰性阳极 电解腐蚀行为的影响

本文采用两步烧结法制备铝电解用NiFe_2O_4基金属陶瓷惰性阳极,重点研究了不同阳极电流密度下惰性阳极材料的电解腐蚀行为.实验结果表明:阳极电流密度在0. 2～1. 2 A/cm~2之间时,槽电压相对稳定,波动幅度较小,表现出良好的稳定性;阳极电流密度在1. 4 A/cm~2时,槽电压波动较大.电解后阳极尺寸无明显变化,棱角分明,与电解液接触面平整,无开裂、肿胀以及表层剥离的现象.从微观形貌和微区面扫描成分分析可知,阳极腐蚀速率随电流密度的增加先降低后增加.阳极电流密度为0. 8 A/cm~2时阳极腐蚀速率最低,产品铝中主要Cu、Ni和Fe杂质元素总含量最低.     

金属陶瓷5Cu/(10NiO-NiFe2O4)在KF(K3AlF6)-AlF3-Al2O3 熔体中的电解腐蚀

采用粉末冶金技术,制备出组成为5Cu/(10NiO-NiFe-2O-4)的金属陶瓷惰性阳极,并对其在电解质KF(K-3AlF-6)-AlF-3-Al-2O-3熔体中的电解腐蚀行为进行了研究.实验结果表明,对于添加KF或K-3AlF-6的电解质组成,电解质中杂质元素浓度在电解初期相对稳定,而后呈上升趋势;由于铝热还原反应的加剧,电解后阳极腐蚀严重;与传统电解质组成相比,采用低温电解质有利于减缓NiFe-2O-4基金属陶瓷惰性阳极的腐蚀,但需提高熔体导电能力和解决电解过程阴极结壳等问题.     

铝电解惰性阳极材料的研究现状

针对铝工业现状，介绍近年来人们在惰性阳极方面所做的研究，包括金属惰性阳极、金属陶瓷、金属氧化物陶瓷、氧化铈涂层等。着重介绍了国内对金属陶瓷惰性阳极材料的研究现状。     

铝电解惰性阳极材料研究现状

论述了铝电解工业中使用惰性阳极的意义,提出惰性阳极应符合的标准并对惰性阳极的优缺点进行了分析.综述了国内外近年来对于合金阳极、氧化锡阳极、金属陶瓷阳极及氧化铈涂层阳极等惰性阳极材料的研究成果,总结了目前惰性阳极材料研究亟待解决的主要问题.     

铝电解惰性阳极材料选择的研究

论述了传统碳素阳极的缺点及使用惰性阳极的意义,提出了惰性阳极材料应符合的要求。综述了国内外对金属氧化物陶瓷阳极、金属陶瓷阳极、金属阳极的研究成果,并总结了以上三类惰性阳极有待进一步解决的主要问题。     

铝电解用惰性阳极的研究进展

介绍了国内外铝电解惰性阳极方面较有影响的研究工作,探讨了金属、陶瓷和金属陶瓷基惰性阳极选材问题,分析了惰性阳极在研究和应用中出现的一些问题,认为惰性阳极应用于工业生产中还有很长的路要走,希望相关领域的精英参与惰性阳极的研制工作。     

5Cu/(10NiO-NiFe2O4)金属陶瓷惰性阳极钠钾混合电解质电解腐蚀研究

采用传统粉末冶金技术制备了铝电解用5Cu/(NiFe2O4-10NiO)金属陶瓷惰性阳极,对其在钠钾冰晶石混合冰晶石中进行电解腐蚀。研究结果表明,从微观来看,阳极存在腐蚀现象。电解过程的槽电压波动剧烈。Fe、Ni和Cu组元的平衡浓度分别为150×10-6、42×10-6及40×10-6,腐蚀速率比常规电解条件下的低。     

铝电解惰性阳极在熔融电解质中腐蚀过程的研究进展

惰性阳极是原铝生产保持低碳化的重要研究方向,近些年,惰性阳极材料的研究取得长足进展。通过对惰性阳极材料进行分类,综述了不同种类(合金阳极、氧化物陶瓷阳极和金属陶瓷阳极)的惰性阳极在熔盐电解质中可能发生的腐蚀反应,主要探究发生的化学腐蚀和电化学腐蚀,以及腐蚀后可能对阳极的影响。明晰增加阳极耐腐蚀性的方法,或者通过抑制腐蚀反应的进行,来降低惰性阳极在冰晶石熔盐中的腐蚀速率,从而促进惰性阳极在铝电解行业中的可行性发展。     

铝电解用NiFe2O4型金属陶瓷惰性阳极的研究进展

介绍了国内外铝电解用NiFe2O4型惰性阳极材料的研究与开发进展情况,指出了该材料具有耐熔盐腐蚀、抗氧化和电阻率低等优点的同时也存在抗热震性能差和电连接困难等缺陷.此外,简要阐述了NiFe2O4型惰性阳极的主要制备工艺.     

尖晶石基铝电解惰性阳极的研究进展

惰性阳极是铝电解行业比较关注且极富挑战性的课题。本文主要论述了惰性阳极的研究进展及国内外现状，重点阐述了氧化物阳极(SnO2基氧化物阳极及铁酸盐阳极)、金属陶瓷及氧化铈涂层等．并且只有惰性阳极 可润湿性阴极的新型电解槽同时使用才能达到人们所期望的降低能耗、消除污染、降低成本的目的。     

Studies on the corrosion and the behavior of inert anodes in aluminum electrolysis

The corrosion rates of inert anodes based on tin oxide and nickel ferrite cermet materials were studied as a function of some operating parameters. To reach a better understanding of the corrosion mechanism, the behavior of the anodes was observed under some specific conditions, such as in pure cryolite, at high current densities, at different potentials, and at varying cathode surface areas. It was confirmed that low alumina concentrations led to catastrophic corrosion of the anodes and that high current densities and high as well as low NaF/AlF₃ molar ratios were also detrimental. The corrosion rate of tin oxide based anodes showed a minimum (so-called “normal corrosion”) at anodic potentials of 2.2 to 2.4 V with respect to aluminum. The normal corrosion is due to chemical dissolution of the anode material and reduction of the corrosion products into the cathode metal. The corrosion rate increased with increasing cathode surface area. At potentials higher than ～2.5 V, the anodes showed catastrophic corrosion. Catastrophic corrosion can be ascribed to decomposition of the anode material by depletion of alumina at the anode surface provoked by low bulk concentration of alumina and/or high current density.     

NiFe2O4基惰性阳极抗热震性的研究进展

综述了铝电解用NiFe2O4型惰性阳极材料抗热震性能的研究现状。简要的介绍了材料抗热震断裂的理论,评述了NiFe2O4基金属陶瓷抗热震性的有关研究情况,概述了NiFe2O4型惰性阳极今后的研究重点及发展方向。     

A pilot-scale trial of an improved galvanic deoxidation process for refining molten copper

A laboratory-scale galvanic deoxidation technology developed by earlier workers has been improved, with the aim of developing a prototype pilot-scale deoxidation unit. Each deoxidation cell consists of a one end-closed yttria-stabilized zirconia (YSZ) tube coated with a Ni-YSZ cermet anode on the inner walls. The YSZ tube is immersed, with its closed end in the metallic melt, and an oxygen-chemical-potential gradient across the tube is established by passing a reducing gas through the tube. The melt is then deoxidized by short circuiting it with the anode. Through laboratory experimentation, the nature of the anode/electrolyte interface adhesion was identified to be an important factor in obtaining enhanced deoxidation kinetics. The kinetics of oxygen removal from the melt was increased by an order of magnitude with an improved anode/electrolyte interface. A pilot-scale refining unit consisting of 53 cells with the improved anode/electrolyte interface was manufactured, and a field evaluation of the galvanic deoxidation of copper was conducted. The deoxidation-process model was modified to include multiple deoxidation cells, which were required for the pilot-scale trials, and to analyze the effect of electrolyte/electrode adhesion on deoxidation kinetics. Preliminary studies on process component lifetimes were conducted by investigating the thermal cycling, corrosion behavior of the electrolyte, and stability of the cermet anode structure. Based on the results of the field trial and the analyses of the process component lifetime, future work needed toward commercializing the technology is discussed.     

Corrosion of Zinc Ferrite Based Inert Anodes in AlF3-NaF-Al2O3 Melts Under Conditions of Anodic Polarization

ZnFe2O4-based inert anodes were made to conduct the aluminum electrolysis tests. The corrosion behaviors of the inert anodes were examined and discussed. Experiment results prove that: (1) ZnFe2O4-based inert anodes are good corrosion resistant to AlF3-NaF-Al2O3 melts under the conditions of anodic polarization; (2) High anodic current density(＞1.5 A·cm-2), high alumina concentration and low ratio of NaF/AlF3 in the molten salts will be the most important conditions for using inert anode.     

Character of the corrosion destruction of inert anodes during electrolysis of cryolite alumina melt and the reasons for it

The behavior of inert anodes during the electrolysis of the cryolite alumina melt in a laboratory electrolyzer is investigated at 960°C. On the basis of the electrolysis tests of more than 150 anodes with various structures and compositions, the character of their corrosion and possible reasons for it are revealed. It is shown that the physical and physical-chemical processes of the interaction of the molten electrolyte and oxygen evolved from the anode material are the basis of the phenomena of the corrosion destruction of anodes. The requirements for increasing the corrosion stability of the structure of inert anodes are formulated.     

渗氮处理对金属陶瓷耐蚀性的影响

针对金属陶瓷耐腐蚀性不足的特点,采用真空烧结后渗氮的方法制备出表层富氮的金属陶瓷,并分析试样的微观结构,测试其力学和物理性能、耐腐蚀性能.结果表明,与常规金属陶瓷对比,渗氮后金属陶瓷的综合性能提高,且在酸、碱介质中的耐腐蚀性有所提高;渗氮后试样表面Ti含量提高,硬度提高,有利于改善金属陶瓷的机械性能和耐腐蚀性.