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…     

浅谈我国电解铝工业集中度

利用绝对集中度（CRn）和赫芬达尔指数（HI）计算仑式．对我国电解铝工业近十年来的有关数据进行分析研究,定量分析了我国电解铝工业集中度的现状,并分析了电解铝工业上下游产业的集中度．通过产业结构分析．指出电解铝工业集中度较低．影响了电解铝工业的市场竞争力．应提高电解铝工业的集中度。     

关于铝电解用预焙阳极高度的探讨

指出铝电解用的预焙阳极高度的选择,直接影响到铝电解槽的阳极电压降、直流电耗、阳极消耗量等技术指标。因此,选用何种高度的预焙阳极,是电解槽设计的一个重要条件。本文通过两种高度的预焙阳极的使用效果对比,阐述了适当提高预焙阳极高度的可能性和可操作性。     

铝电解中二氧化锡基（氢气）气体阳极

开发一种在低温电解质（850℃）铝电解中应用的新型二氧化锡基气体阳极以降低铝电解能耗和二氧化碳排放。在此种气体阳极中,氢气通入阳极后参与阳极反应,分别用石墨和铝作阴极和参比电极。采用循环伏安法研究此体系中铂和二氧化锡基电极上氧离子的电化学行为,并确定氧气的析出电势。然后,采用气体电极进行恒电流电解实验,相对于未通入气体和通入氩气,通入氢气后阳极出现明显的去极化现象（阳极电势约下降0.8 V）。实验结果表明,氢气已参与阳极三相界面（气体-电解质-电极）反应,为还原性气体阳极在铝电解上的应用提供了可行性。     

热模模压制取铝电解阳极炭块

采用热模模压法制备铝电解阳极炭块,并对制取的阳极炭块的物理化学性能进行测试。研究模压工艺和沥青添加量对预焙阳极炭块体积密度、抗压强度和抗氧化性的影响。采用扫描电镜对炭块的微观结构进行分析,对热模模压生产阳极炭块的机理进行探讨。结果表明：采用热模模压法生产炭阳极可使沥青进入石油焦颗粒的内部,并填充石油焦颗粒内部的气孔,从而减少预焙阳极炭块的气孔率,提高其密度。采用热模模压生产的预焙阳极炭块的体积密度为1．64～1．66g／cm3,比工业阳极炭块的体积密度增加0．08～0．12g／cm3,同时其抗氧化性能也获得妨大的辑高．     

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.     

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.     

电解铝炭素阳极消耗研究评述

电解铝过程中，炭素阳极的实际消耗远高于其理论消耗，直接影响原铝的生产成本。本文在分析铝用炭素阳极消耗机理的基础上，评述了阳极生产和电解铝生产中的诸多因素对炭素阳极消耗的影响，这些因素包括：阳极电流密度、石油焦煅烧温度、阳极焙烧温度、电解槽操作温度、阳极硫含量、阳极金属杂质、残极和灰分、阳极添加剂、电解质添加剂、阳极配方的沥青用量和阳极保护措施等。     

Expanded Industrial Experiments of Free-alkali Recovery from Sodium Tungstate Solution by the Membrane Electrolysis Process

The technology of electrolysis with ion-exchange membrane has been widely applied in industry [11. The free-alkali recovery from sodiumtungstate solution by electyolysis with ion-exchange membrane has been stUdied in our laboratory. After success in exploratory test, furtherstudies were made on the anode of the electfolysis, the structUre of the electrolytic tank and theassemblage of the electfolytic cell, and someachievements have been obtained [2--4]. Basedon these results, the expanded exp…     

电解废旧铝合金回收铝的电流效率(英文)

研究在AlC13-NaCl熔融盐体系中进行电精炼废旧铝合金回收金属铝。以铝合金为阳极,通过直流电沉积在铜阴极上得到铝涂层。在170°C、电流密度100 mA/cm2下电解4 h,得到的沉积物铝的纯度大约为99.7%,电流效率为44%~64%,每千克铝消耗电能3~9 kW·h。探讨阴极电流密度、电解质成分和电解时间及温度等对铝沉积电流效率的影响。结果表明:在AlCl3和NaCl摩尔比为1.3~1.9时,AlCl3和NaCl摩尔比对电流效率的影响很小,升高电解温度有利于提高电流效率;但是延长电解时间或增大电流密度会导致电流效率降低。电流效率的降低主要是由于沉积的铝呈现枝状晶或粉化而易从阴极上脱落到电解质中所致。     

160kA预焙铝电解槽区域电流效率

论述了区域电流效率的意义，利用电流效率综合机理模型格区域参数估计模型计算出了１６０Ａ预焙槽的区域电流效率。结果表明，１６０ＫＡ预焙蝇各区域的电流效率很不均匀，最大值与最小值相差２０％以上，阳极义 区域电流效率相差可达４％以上，采用区域电流效率的观点，分析了某厂１６０ＫＡ预焙铝电解槽电流电流效率的特点，认为低电流效应区域的存在和面积偏大导致电解槽平均电流效率偏低，并由此提出了提高电流效率的途径。     

Resistance due to gas bubbles in aluminum reduction cells

The contribution of gas bubbles to electrical resistance in aluminum reduction cells is becoming increasingly important as smelters attempt to reduce energy consumption. A prime example is the widespread introduction of slotted anodes to encourage faster gas bubble release from under the anodes. However, quantification of the bubble resistance is difficult, which makes evaluation of process changes problematic. Studies of the effect of bubbles on electrical resistance in industrial cells, laboratory-scale electrolysis experiments, and physical models are reviewed in this paper.     

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。     

LOW TEMPERATURE ALUMINUM FLOATING ELECTROLYSIS IN HEAVY ELECTROLYTE Na_3AlF_6-AlF_3-BaC1_2-NaCl BATH SYSTEM

1. IntroductionSince the Hall--Heroult process was invented one hundred years ago, it has been the onlyaluminum production method in the w..ldll]. The process has many weak points, such aslow unit productivity; low energy utilization, less than 50%; high electrolytic temperature,usually at 950ap; high consumption of carbon material; serious environmental pollutionand so on. It is well known that the melting point of aluminum is 660ap, therefore, aluminum electrolysis at the range of 700--800C…     

铝电解槽热电场的有限元分析

运用大型有限元分析软件ANSYS中附带的APDL模块解决铝电解槽热非线性和炉帮形状的循环计算问题,充分考虑电解质发生相变时产生的潜热,建立了热电场数学模型,开发了准三维热电耦合模型.选择普通炭块和碳化硅作为侧部保温材料两种情况,对我国300 kA侧部五点进电预焙铝电解槽进行了热电耦合分析,绘出了热场等温线图.结果表明,300 kA侧部五点进电预焙电解槽的阴极和侧部炭块的设计是合理的.     

Electrolysis of Magnesia from Bischofite in Qinghai Salt Lakes

1 IntroductionMagnesium industry is confronted with animPortant seedtime in China because of the im-petuous1y extended aPplications of magnestumand its alIoys. The development of magnesiummetallurgy industry finally depends on whetheror not lowering production cost and taking pallin international comPetition[l]. Chaerhan SaltLake in Qinghai province of China, located atthe south central of Chaidamu basin, has exten-sive reserves of about l.62xl09 t magnesiumchloride. In the production proc…     

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。     

Ambient temperature cured TiB_2 cathode coating for aluminum electrolysis

1　INTRODUCTIONAluminumindustryhasbeendevelopingrapidlyinChinainrecentyears ,soderbergcellshavebeenre placedwithmodernprebakecellsinmanyaluminumsmelters,theaveragecelllifehowever ,forprebakecellsinourcountrywasonlyabout130 0d ,muchlowerthantheaveragecelllife ,i.e .above 2 5 0 0d ,forthecellsindevelopedcountries .TiB2 cathodecoating (TCC)couldbeoneofthesolutionstoreducegreatlytheopportunitytotheearlyfailureofcellsandextendthecelllifeofprebakecell[14 ] .Theconceptoftitaniumdiboride (TiB2 …     

面向铝电解槽的变论域模糊专家系统

在铝电解过程中有很多参数影响电流效率和电解槽的稳定性。AlF3添加量和出铝量是2个影响铝电解生产经济效益的重要因素。模糊逻辑提供一种合适的机制来描述铝电解过程参数与电流效率之间的关系。在铝电解过程中,采用基于Mamdani模糊推理过程的模糊专家系统调整AlF3添加量和出铝量。系统应用一种新的变论域方法,解决不同电解槽具有不同参数论域的问题,并将系统应用于某电解厂的300kA铝电解槽中。实验结果表明,电解质温度稳定在945℃～955℃,电流效率达到93.5%,吨铝直流电耗为13000kW·h。