Industrial preparation and performance testing of property-modified prebaked carbon anodes for aluminum electrolysis

1　ＩＮＴＲＯＤＵＣＴＩＯＮＩｔｉｓｗｅｌｌｋｎｏｗｎｔｈａｔａｌｕｍｉｎｕｍｅｌｅｃｔｒｏｌｙｓｉｓｉｓａ“ｌａｒｇｅｆａｍｉｌｙ”ｏｆｅｌｅｃｔｒｏｅｎｅｒｇｙｃｏｎｓｕｍｐｔｉｏｎ .Ｉｎｔｈｅｍｅａｎｔｉｍｅ ,ｃａｒｂｏｎａｎｏｄｅｓａｒｅｕｓｅｄｕｐｃｏｎｔｉｎｕｏｕｓｌｙｉｎｔｈｅｐｒｏｃｅｓｓｏｆｅｌｅｃｔｒｏｌｙｓｉｓ ,ｓｏｔｈｅａｌｕｍｉｎｕｍｅｌｅｃｔｒｏｌｙｓｉｓｉｓａｌ ｓｏｃａｌｌｅｄ“ｌａｒｇｅｆａｍｉｌｙ”ｏｆｃａｒｂｏｎｃｏｎｓｕｍｐｔｉｏｎ .Ｆｏｒａｌｏｎｇｔｉｍｅ…     

Pilot study of mechanism of property-modified anode in aluminum electrolysis

1　INTRODUCTIONAluminummetallurgyadoptsthemethodofhightemperaturemeltsaltelectrolysisdevelopedonehun dredyearsago .Intheprocessofresearchanddevel opmentinthisfield ,physicalchemistry ,electro chemistry ,materialscience ,roboticizedtechnologyandsoonwerecombinedwithaluminummetallurgytechniques,makingthebasicprincipleoftheHall Heroultprocessbeingmoredeeplyrealizedbypeople .Furthermore ,thistechnologywasdevelopedcon stantlyandbecamemoreandmoreperfectinordertofurthersaveenergy ,reducerawmateri…     

铝电解用改性预焙碳阳极实验室研究

为了制备能应用于工业生产节能降耗和增效的改性预焙碳阳极，首先在实验室进行了阳极添加剂组分的选择优化及复合添加剂的合成，筛选出了含有A1，Mg，F，O等多种元素的复合添加剂，制备出含有该类复合添加剂的AB类改性预焙碳阳极，并对其进行了物理化学性能和电化学性能的测试。实验室研究表明，与对比(空白)阳极相比，含有AB类添加剂的改性预焙碳阳极具有理想的节(电)能和节(碳)耗效果。重点阐述了AB类改性预焙碳阳极的各项性能。     

Preparation and preliminary testing of cermet inert anode for aluminum electrolysis

1　INTRODUCTIONAluminumhasthelargest productivityamongthenonferrousmetals ,2 4Mtperyearintheworld .Whilegreatprogresshavebeenmadeintheprimaryaluminum production ,theindustrycontinuestopur sueresearchtosolvesomeformidablechallenges ,suchas quitealargeenergyintensity(14 0 0 0 15 0 0 0kW·hpertonaluminum) ,highcon sumptionofcarbonanode(5 0 0 6 0 0kgpertonalu minum) ,significantemissionsofgreenhousegas(1.71tpertonaluminum )andotherdetrimentalgases ,highcapitalinvestmentandcost[1] .Inertelectr…     

Electrocatalysis of carbon anode in aluminium electrolysis

The anodic overvoltage of the carbon anode in aluminum electrolysis is of the order of 0.6 V at normal currem densities. However, it can be reduced somewhat by doping the anode carbon with various inorganic compounds. A new apparatus was designed to improve the precision of overvoltage measurements. Anodes were doped with MgAl2O4 and AlF3both by impregnation of the coke and by adding powder, and the measured overvoltage was compared with that of undoped samples. For prebake type anodes baked at around 1150℃, the anodic overvoltage was reduced by 40-60 mV,and for Soderberg type anodes, baked at 950 ℃, by 60-80 mV.     

预焙阳极铝电解槽阳极电、热场的数值仿真与优化

根据傅里叶传热定律和基尔霍夫导电定律，建立了预焙阳极铝电解槽阳极传热、导电的数学模型。用三维控制容积法推导了传热、导电的有限差分方程。在合适的边界条件假定下，采用C语言编程对其进行耦合数值求解，以此确定阳极内部的电位分布和温度分布，并分析了阳极的热平衡状态。通过模拟计算给出阳极和钢爪尺寸对电、热场和热平衡的影响，以此指导设计出阳极电位降尽可能小和散热量尽可能少的阳极和钢爪尺寸。     

电解铝炭素阳极用氧化铝溶胶抗氧化复合涂层

提出采用在炭素阳极表面原位固化制备以氧化铝溶胶为基本粘结相、相对致密的氧化铝涂层(膜)的方法,达到减少阳极氧化、降低阳极过量消耗的目的。在阳极炭块上制备了氧化铝溶胶复合涂层,并检测了其基本性能。结果表明,由室温至900℃,涂层阳极试样的热失重率比裸阳极降低了50%;涂层较为致密,即使是放大2000倍,也未见孔洞和裂纹;平均孔径只有几个纳米,且高温时涂层的平均孔径比低温时要小,900℃时涂层的平均孔径比600℃时小了近1/3;涂层不仅在不同的温度下都能对炭素阳极起到较强的保护作用,而且还能起到提高炭素阳极初始剧烈氧化温度点的作用。     

Effect of aluminum-containing additives on the reactivity in air and CO2 of carbon anode for aluminum electrolysis

Airbum reaction and carboxy reaction result in the excess consumption of carbon anode in aluminum electrolysis.To reduce the excess carbon consumption, carbon anode was doped with aluminum-containing additives, such as A1, Al4C3,AlF3 and Al2O3. Their reactivity in air and CO2 was determined with an isothermal-gravimetric method to study the effect of aluminum-containing additives on the reactivity in air and CO2 of carbon anode. Results shown that the airbum reactivity at 450℃ and carboxy reactivity at 970℃ of carbon anode both decreased with Al-containing additives adding, while shown a minimum with the amount of Al4C3, AlF3 and Al2O3 increasing. However, all Al-containing additives increase the alrbum reactivity at 550℃ of carbon anodes. Coke yield measurement and XRD examination with aluminum containing additives doped pitch cokes revealed that the effect of Al-containing additives on the airburn reactivity and carboxy reactivity of carbon anode would result from chemical factors and structural factors.     

新型炼铝电极材料

研制了一种新型铝电解金属陶瓷惰性阳极,阳极基体由Fe-Ni-Co-Al-O构成.在电解温度960℃,氧化铝质量浓度为6.0%,阳极电流密度为1.0 A/cm2,分子比为2.6的电解质中对其进行了10 h的电解.电解过程平稳,电解铝产品纯度达到96%～99%,阳极气体中氧气的含量为98%,反电动势为2.45 V,高于理论值0.25～0.35 V.此阳极具备较好的导电性、抗氧化和耐腐蚀性.采用X射线衍射和电子探针微分析仪(EPMA)对电解后的阳极进行分析,发现阳极表面存在铁酸镍、铝酸铁等尖晶石型化合物,阳极表面下层为铝酸铁、钴酸镍等陶瓷相以及金属相;金属相和陶瓷相相互弥散分布构成结构致密的金属陶瓷层.     

铝电解用炭阳极的综合性能

在阐述了炭阳极在铝电解生产中所起的重要作用的基础上，对我国铝电解用炭阳极的物理化学性能和电化学性能进行了综合评述，并指出了我国铝电解用炭阳极存在的不足，最后阐述了目前阳极质量改进的一些途径，并从阳极添加剂技术的角度对我国铝电解用炭阳极质量的改进提出了系列建议。     

铝电解中阳极涂层与磷生铁改性剂的综合优化实验

提高炭素阳极的强度和抗氧化性是目前铝电解研究的热点和难点.本文总结了在某铝厂400 kA系列磷生铁中加入改性剂和在阳极炭素表面涂盖耐高温防氧化涂层涂料的实验.加入磷生铁改性剂浇筑出的磷生铁具备更好的延展性和膨胀性,使炭块与钢爪之间接触电阻减少,钢爪与炭块间的连接更紧密,减少了脱极的几率,降低了铁?碳压降;使用防氧化涂层...     

Results from 100 h electrolysis testing of NiFe2O4 based cermet as inert anode in aluminum reduction

1 Introduction Since the Hall-Héroult process was applied in aluminum production, an inert anode was always the target that the aluminum industry was seeking for in the new technology field[1]. Some selection criteria have been defined in order to ident…     

阳极生产脱硫行为对产品质量影响浅析

以铝用预焙阳极生产过程中的脱硫行为为研究对象,分析了石油焦煅烧过程及阳极焙烧过程脱硫对煅烧焦及预焙阳极质量的影响。     

铝电解金属陶瓷惰性阳极的机械加工及大型化研究

本文用普通钻头和设计的专用走具,采用传统机械加工方法对金属陶瓷铝电解惰性阳极钻孔,同时也研究了金属陶瓷惰性阳极的磨削、抛光等加工方法。用这些方法成功地解决了金属陶瓷铝电解惰性阳极的机械加工和大型化问题。     

Preliminary testing of NiFe_2O_4-NiO as ceramic matrix of cermet inert anode in aluminum electrolysis

1　INTRODUCTIONTheideaofusinginertanodes(alsocallednon consumableoroxygen evolvinganodes)inaluminumproductionisasoldastheHall H啨ｒｏｕｌｔｐｒｏｃｅｓｓ ,dat ingbacktothediscoveryofoneoftheinventors ,Hall[1] .Inertanodesareintendedtoreplacethecon sumablecarbonanodethatiscurrentlyused .Withacarbonanode ,thecellreactionisAl2 O3+ 3/ 2C =2Al+ 3/ 2CO2 (1)where　acryolite basedmelt(Na3AlF6 AlF3 CaF2 )atnear 96 0℃servesassolventforthealumina .Withaninertanode ,thecellreactionwillbeAl2 …     

铝电解金属阳极上的气泡析出行为

利用双室透明石英电解槽研究了铝电解金属阳极上气泡的析出行为.实验发现,在低电流密度下,电解开始的一段时间内,新生的氧用于氧化金属阳极表面以形成氧化物膜,此时阳极室没有氧气析出,而阴极室有铝雾扩散; 当形成足够厚的氧化膜后,阳极的氧化速度减慢,阳极表面才析出氧气.在高电流密度下,由于单位时间内在阳极上产生的氧量高于用于氧化金属阳极表面所需的氧量,电解一开始阳极上就有氧气析出.对低电流密度下气泡的生长过程观察发现,气泡先在阳极表面长大,再汇聚成一个或几个大气泡从阳极底部析出,析出前的气泡平均直径随电流密度的增加而减小.     

预焙铝电解槽阳极底部开排气沟对电解质流场的影响

对预焙铝电解槽阳极底部开排气沟时周围电解质流场进行计算,发现部分阳极气体可以通过排气沟向外排放,减少气泡在阳极底部停留时间和阳极底掌气泡覆盖率,从而有利于降低极间电阻压降和阳极效应系数,减少电解能耗;另一方面气体带动电解质进入排气沟,然后进入电解槽侧部通道,扩大了电解质循环通道,促进了阳极周围电解质流动和槽内的传质传热,有利于保持电解正常进行,相比之下排气沟为通沟时较非通沟更有利于保持电解质流动稳定;同时由于排气沟促进了阳极气体排放,使铝液与阳极气体发生“二次反应”(即电解还原的铝卷入电解质中被阳极气体重新氧化)的机会减少,有利于提高铝电解电流效率。     

电解铝阳极导杆铝-钢相位摩擦焊工艺及力学性能

传统的电解铝预焙槽阳极导杆采用爆炸焊块作为过渡实现铝导杆与阳极钢爪的连接. 针对130 mm×130 mm×2 420 mm方铝导杆和端面165 mm×210 mm的铸钢爪,采用相位摩擦焊技术进行焊接,替代原用爆炸块复合焊接的方式,实现自动化生产并达到节能降耗的目的. 通过不同工艺参数的试验研究如:摩擦时间、转速、先顶后刹时间、顶锻压力的改变,通过接头力学拉伸试验、冲击试验、显微组织分析得到了最优工艺参数. 结果表明,最优工艺方法下可得到致密的焊缝组织以及动态再结晶完善的热影响区组织,接头表现出最优的综合力学性能,满足工业生产要求.     

预焙阳极生产工艺导热油输送系统的影响因素

在预焙阳极生产工艺中,采用导热油供热系统进行供热。导热油输送系统是导热油供热系统的重要组成之一。在导热油输送系统设计过程中,对温度、压力的合理设定以及输送方案是否合理将直接影响生产工艺运行和项目投资。本文基于温度和压力的稳定性,对导热油输送系统进行分析,并以常用的两种设计方案为例进行讨论,提出优化建议。     

Densification of Ni-NiFe_2O_4 cermets for aluminum electrolysis

1INTRODUCTION Aluminumelectrolysisconsumesenormous energyandresources,andtheconsumptionwillbeconsiderablydecreasedbyintroductionofinert anodeandwettablecathode.However,underthe toughworkingconditionofaluminumelectrolysis,i.e.highlycorrosiveNa3AlF6Al2O3moltensalts athightemperature(940960℃),theinert anodesnecessaryforthesuccessfulproductionofaluminummighthavethefollowingproperties:be insolubleinafluoridemelt,beresistanttowards anodeoxygen,havegoodelectricalconductivity,possessadequatestr…