铝电解NiFe2O4基金属陶瓷惰性阳极性能研究进展

NiFe2O4基金属陶瓷是最具应用前景的铝电解惰性阳极材料,国内外对其性能与制备技术进行了大量研究。评述了NiFe2O4基金属陶瓷惰性阳极烧结性能、高温导电性能、耐腐蚀性能、高温抗氧化及抗热震性能的最新研究进展及存在的主要问题,探讨了惰性阳极材料的未来研究重点及发展趋势。     

铝电解预焙阳极综合评述

对目前中国铝电解预焙阳极的质量现状进行了综合分析, 指出了存在的主要问题, 并对阳极改进的途径提出了建议。     

锂盐糊阳极在铝电解中的作用机理

往铝电解自焙阳极中添加锂盐，可以增大炭阳极的活性，增进其可湿性，从而降低阳极过电压，减少阳极效应，并且提高电流效率，其综合效果是增产并节电。本文着重讨论其作用机理问题，论证了锂盐对炭阳极的催化作用，减小气膜电阻过电压也是一个重要的节能因素     

低灰煅烧无烟煤与铝用石油焦的性质比较

对煅烧无烟煤和铝用煅烧石油焦的常规性质及颗粒物理性质进行了对比分析,结果表明:煅烧无烟煤的颗粒性质、石墨化度都要优于煅烧石油焦,灰分成份符合铝电解炭阳极原料要求,可以作为铝电解炭阳极的原料使用。     

铝电解用NiO/Fe梯度功能电极的制备及其腐蚀行为

采用传统粉末冶金技术制备铝电解用NiO/Fe金属陶瓷惰性阳极,并研究其在Na3AlF6-Al2O3熔体中的腐蚀行为.结果表明,金属Ni与NiO陶瓷的润湿性能较好,NiO/Fe金属陶瓷的致密化容易实现,表现出相对好的耐蚀性.当分子比=2.3和氧化铝浓度近饱和时电极腐蚀率最小.     

少烟优质阳极糊的研究

对少烟优质阳极糊进行了研究。其措施是：其一对中温沥青进行空气吹炼法改性；其二减少粘结剂沥青的配入量。此外，测试了原料及自焙阳极糊的各种理化性能。测试结果表明：自焙阳极糊的粘结剂需要量是流动性指标和原料性质的函数；自焙阳极糊的生坯表观密度不依流动性指标而变，而是原料性质的函数；所制得的自焙阳极糊其机械强度，孔隙率，比电阻，挥发份都有明显改善，这在铝电解中，对增加电流效率，降低电能单耗有着重大的经济意     

铝电解过程阳极气泡的析出行为

铝电解过程阳极生成的气泡在排放过程中的运动带动电解质的流动,其流动行为影响氧化铝的溶解和金属的二次反应,对电解过程影响较大。采用透明槽进行铝电解实验,用高速照相机和摄像机记录电解过程中的气泡行为并进行分析。结果表明,气泡的生成分为两个阶段：第一个阶段为气泡在阳极底部的生长,第二个阶段为气泡脱离阳极底部在电解质中上升。在阳极电流密度0.7 A/cm2下电解,在气泡生长阶段阳极底部气泡层的最大厚度为0.4 cm,气泡生长到最大需要的时间为12 s,气泡脱离阳极底部在电解质中上升需要的时间为0.27 s。整个电解过程,阳极侧部小气泡不断长大、逸出,采用Matlab数学处理软件,用直方图均衡化方法处理摄像机拍摄的实验图像,可获得阳极侧壁的气泡的生成的清晰图像,用于深入观察和分析气泡的析出行为。     

加强工艺控制 提高铝用阳极质量

由于环保和节能的需要，目前国内外现代化的大型铝厂，普遍采用预焙阳极电解槽。其中预焙阳极的主要作用是两种：导电与参加铝电解的电化学和化学反应，它是电解槽的心脏，在电解过程中起着十分重要的作用。目前，中国铝用阳极材料与国际先进水平的差距之一便是阳极消耗高(中国预焙阳极净消耗平均为450kg/t—Al，而国外先进水平为400～420kg／t—Al)，致使铝电解成本较高、效益较差。     

关于铝电解锂盐阳极糊研究的意见与分歧剖析

从５个方面剖析了铝电解锂盐阳极糊电催化实验研究和工业应用中存在的意见与分歧，分析结果表明，高温熔盐电催化作为电化学与电催化学科的一个新领域，是铝电解节能的一个有效途径，尽管其研究初期存在有不完善地方，但锂盐糊的电催化节能效果这一事实是可信的     

铝电解预焙阳极节能电催化剂的研究

根据著者提出的高温熔盐电解电催化原理，研究了掺杂剂对铝电解炭阳极上阳极反应的电催化作用。电化学测定表明，５０多种掺杂剂中有三种分别掺入炭阳极并在１２００℃下焙烧后仍具有电催化活性。例如，在冰晶石－氧化铝熔体中，１０００℃下在电流密度为０．８Ａ／ｃｍ＾２时，Ｂａ－Ｆｅ电催化剂能降低阳极超电压２００ｍＶ以上；Ｍｇ－Ａｌ电催化剂可降低１７０ｍＶ。对电催化作用机理也作了初步解释。     

Einsatz von Bleilegierungsanoden in Metallgewinnungselektrolysen

In metal electrowinning processes different lead alloys are used as insoluble anodes. Demands on the anode material are low corrosion rates for a long life time, low oxygen overvoltage to minimize the specific energy consumption and good mechanical stability. In recent years, mainly the production processes and the concentration range of the alloying elements were optimized to improve the anode properties. Steps of this development were transferred from investigations to optimize the grid materials for lead SLI accumulators. In copper electrowinning the PbSb anodes used in the past have been replaced to a large extent by PbSnCa alloys. These anodes have relatively good mechanical properties and a sufficient corrosion rate, but a relatively high anode potential. Until now, in zinc electrowinning anodes made of PbAg alloys are used.     

Anode effects in electrowinning

In traditional electrowinning operations, metal particles from commercial insoluble anodes flake off the immersed surfaces under high current densities and thus become occluded on the adjacent cathode surface thereby impairing the cathode product quality and market grade. This results in an undersirable physical appearance of the cathode due to irregular protrusions which impede subsequent material handling operations such as packaging, weighing and shipping. The paper serves to highlight the existing problems inherent with permanent anodes and suggests possible areas for further research and development studies.At present, permanent anodes are employed in the worldwide electrolytic industry for the recovery of base metals such as copper, nickel, cobalt, and zinc while smaller scale operations exist to recover precious metals such as gold and silver from leach solutions. The coupling of solvent extraction with electrowinning technology (SX-EW) is now a widespread practice. Unfortunately, the usage of permanent anodes has the disadvantages of ongoing maintenance costs to clean the anode surfaces and refurbish the wetted area, results in lower anode useful life, the expense of anode replacement, lower current efficiency, higher power consumption as compared to electrorefining, and inferior cathode quality which becomes contaminated due to deterioration of the metal or metal alloy used to fabricate the insoluble anodes.Apart from improvements in productivity and cathode product quality, and lower labour requirements, the driving force to remedy present electrowinning performance is mainly a reduction in energy. Another associated problem area is the usage of mother blanks fabricated from either aluminum, copper, titanium, or stainless steel as employed to enable full deposit stripping. It is recognized that the construction of the different hanger bars used to support both permanent anodes and mother blanks presents another problem area for study which is addressed within the paper. The writers advocate investigations to improve non-ferrous metal stripping practice, increase current efficiency and extend the useful life of permanent electrodes. The anticipated improvement in full plate cathode chemical and physical quality will benefit downstream operations such as copper wirerod production and subsequent fine wire drawing.     

Sn对AP65镁阳极显微组织和电化学性能的影响

采用熔炼法制备了Mg-6%Al-5%Pb-Sn镁阳极材料。采用金相显微镜(OM)、扫描电镜(SEM)、浸泡法、恒电流极化法和动电位扫描法分别研究了不同Sn含量对AP65镁阳极显微组织和电化学性能的影响。结果表明: 加Sn后镁阳极显微组织中产生条形Mg₂Sn相, 主要分布于基体晶界, 且Mg₂Sn相含量随着Sn含量增加而增多;Mg-6%Al-5%Pb-2.0%Sn镁阳极析氢速率、失重速率、自腐蚀速率最小, 而腐蚀电位、腐蚀电流密度、工作电位和阳极使用效率最高。随着Sn含量增加, 镁阳极腐蚀微裂坑和腐蚀产物减少, 镁阳极溶解速率降低。     

Process metallurgical research activities at Delft University of Technology, Netherlands

Investigations on alternative aluminium production — Study on melting and recyclability of aluminium scrap — Modelling the scrap melting in a rotary furnace for aluminium recycling — Characterization and recycling of various coated magnesium scrap — Thermal processing of solid waste and incineration residues     

添加剂对一水硬铝石型铝土矿焙烧强化溶出的影响

研究了在一水硬铝石型铝土矿焙烧过程中添加剂对焙烧矿溶出性能的影响。实验结果表明, 在一水硬铝石型铝土矿焙烧过程中添加氟化铝, 对焙烧矿的溶出性能有明显的改善作用。在铝土矿中添加1%的氟化铝焙烧, 经185 ℃溶出1 h 后, 焙烧矿氧化铝的溶出率达52%, 比未添加时提高15%左右;且随着氟化铝添加量的增加, 氧化铝的溶出率随之升高, 当添加量为5%时, 在同样溶出条件下氧化铝溶出率可达71%;而铝土矿添加3%氟化铝焙烧, 在200 ℃溶出1 h, 氧化铝溶出率即可达到88%。     

Characterisation and treatment of Australian salt cakes by aqueous leaching

Salt cakes are complex waste products derived from the melting of aluminium drosses to recover some of the metallic aluminium present. This paper reports the results of detailed characterisation studies on two different Australian salt cakes and proposes a flowsheet that could be used to render the salt cakes less toxic, reduce waste volumes for disposal, and, importantly, recover valuable products from them.Characterisation data showed that the salt cakes contained at least 12 major metals present in at least 19 identifiable phases. Typical total aluminium levels were 37% with the aluminium present in at least 13 phases. Potentially valuable components identified included aluminium metal, salt (NaCl and KCl), and residual aluminium units.Coarse aluminium metal was recovered in a high grade product by grinding and screening. Various aqueous treatments were then investigated to extract soluble salts and decompose aluminium nitrides and carbides present. Variables considered included leach feed size (−2 mm or finely ground), leach time (0–4 h), temperature (25 °C or 60 °C), and lixiviant type (water or 16% w/v NaOH). Typically more than 90% of the chlorides were extracted within 1 h. Full decomposition of nitrides present, however, was only achieved with hot alkaline leaching of finely ground salt cake. Over 40% of the residual alumina present in the leach residues was readily extracted using Bayer digestion conditions.Based on these results, and practical considerations, an integrated flowsheet for the treatment of salt cakes is proposed. This involves crushing and screening the salt cake to recover coarse aluminium metal, followed by wet grinding and screening to recover fine metallic aluminium. Screen undersize material is then leached in cold water and the pulp filtered and washed. The solution is evaporated in solar ponds to recover the dissolved salts for recycling, while the leach residues can be treated in a Bayer digestion plant to recover residual aluminium units.     

“一步法”铝粉除钒工艺及其反应机理刘水根 邓国珠

本文论述了“一步法”铝粉除钒精制四氯化钛工艺的优缺点及反应机理,比较了“一步法”铝粉除钒和“两步法”铝粉除钒的不同,“一步法”铝粉除钒新工艺比“两步法”铝粉除钒工艺具有更多的优点。     

三点进电母线配置的预焙槽三维磁场数值计算

应用等效磁偶极子法开发了预焙铝电解槽磁场计算软件,并应用到某厂82kA三点进电预焙铝电解槽的磁场计算。计算结果表明:水平磁场基本上形成一个顺时针的漩涡,两个大面处的磁感应强度较大,中间的磁感应强度较小;垂直磁场沿长轴及短轴方向都呈反对称分布,极值出现在电解槽的四个角部。与实测比较,计算结果较为准确,可以满足铝电解槽母线设计时的磁场仿真计算的要求;同时表明,由自焙槽改预焙槽时,采用第三点补偿母线的方式是可取的。