铝电解槽阴极用炭素材料现状分析

回顾了铝电解槽用冷捣糊材料的发展历程,总结了其主要应用类型和生产工艺,归纳阐述了几种铝电解槽阴极材料的制作方法,并研究讨论了冷捣糊的发展趋势。系统比较了传统炭砖筑炉工艺及冷捣糊整体筑炉工艺的各项指标,提出我国铝电解槽炉衬成型的方式正在朝整体筑炉的方向发展,冷捣糊的发展方向是整体炉衬用冷捣糊。     

利用炭块加工除尘粉生产铝用阴极糊

根据大型预焙电解槽对阴极糊的工艺技术要求,利用炭块加工除尘粉,成功地开发出了高质量的铝用阴极糊.经用户对阴极糊的实际使用,效果良好.     

我国铝电解用冷捣糊材料的研究现状

对冷捣糊材料进行了简要概述,总结了2011年至今,我国铝用冷捣糊材料的研究现状,并在此基础上结合国外的研究,探讨我国铝电解用冷捣糊的主要发展方向。发现用树脂系冷捣糊材料填充铝电解槽阴极炭块之间的缝隙,能够提高电解槽寿命,减少有害物质的释放,从而缩小与国际先进水平之间的差距。     

文摘

20 0 10 0 7石油焦对我国电解铝用预焙阳极质量的影响 [刊 ,中 ]/罗英涛 ,王平甫∥轻金属 ,2 0 0 1,(1) :48～ 5 2论述了石油焦对电解铝用的预焙阳极质量的影响 ,指出我国铝用石油焦存在的科研和检测技术滞后、质量波动大、粉焦量大、石油焦的技术标准不适于现代大型预焙铝电解槽阳极要求等问题、并提出改进建议。图 2表 4参 102 0 0 10 0 8铝用ＴｉＢ2 -Ｃ复合阴极炭块的开发与应用 [刊 ,中 ]/成庚∥轻金属 ,2 0 0 1,(2 ) :5 0～ 5 2介绍了一体化成型ＴｉＢ2 -Ｃ复合层阴极炭块和ＴｉＢ2 -Ｃ复合冷捣糊的研制、产品检测 ,在 75ｋＡ工业预焙…     

铝用炭素材料

1 .2 .5　冷捣糊 (ｃｏｌｄｒａｍｍｉｎｇｐａｓｔｅ)冷捣糊是一种可在室温下砌筑施工的阴极糊 ,这种阴极糊的骨料与普通阴极糊 (也称热捣糊 )相同 ,如普煅无烟煤或电煅无烟煤、冶金焦、石墨碎等。粘结剂为低软化点的混合粘结剂 ,一般为中温煤沥青与蒽油或煤焦油混合使用 ,其软化点为 (2 0± 5)℃。冷捣糊的软化点低 ,挥发分高 ,包装应用编织袋、塑料袋双层包装 ,其保质期为 6～ 9个月。冷捣糊的施工温度为 2 5～ 50℃ ,夏季可在环境温度下施工 ;春秋季可以通过焖糊来弥补环境温度低带来的影响 ,焖糊温度为 4 0～ 50℃ ;北方冬天筑炉会影响…     

中国高品质阴极炭块的工业生产及应用

综述了近几年中国高品质阴极炭块的生产技术及现状,研究了石墨含量对阴极炭块各项理化指标的影响,随着石墨含量的增加,阴极炭块的导电、导热性提高,抗电解质侵蚀性能明显增强,耐压强度有所降低。成型技术对石墨化阴极炭块的各向异性有明显的影响,振动成型生产的石墨化阴极炭块的各向异性不明显。总结了高石墨质阴极炭块、石墨化阴极炭块、硼化钛可湿润阴极炭块在大型预焙铝电解槽上的工业试验结果,高品质阴极炭块使大型槽的生产更平稳,能够提高电流效率、降低电耗和延长电解槽寿命。并初步分析了其技术经济性。     

石墨化阴极铝电解槽电热场仿真研究

将工业试验测试与数值仿真方法相结合,以ANSYS软件为主要开发工具,建立有限元模型对300kA石墨化阴极铝电解槽的电-热场进行计算分析,并与测试结果进行了比较和讨论。研究表明,石墨化阴极炭块内温度梯度相对普通阴极更小,温度分布更加均匀;配合使用碳化硅侧块能增强电解槽散热能力,可以有效加强大型预焙槽的散热。     

低温用冷捣糊的研制

本文介绍了低温用半石墨质冷捣糊的生产工艺与条件，为炭素厂生产冷捣糊提供了一个新的途径。     

铝用炭素材料(续10)

1.2.5 冷捣糊(cold ramming paste) 冷捣糊是一种可在室温下砌筑施工的阴极糊,这种阴极糊的骨料与普通阴极糊(也称热捣糊)相同,如普煅无烟煤或电煅无烟煤、冶金焦、石墨碎等.粘结剂为低软化点的混合粘结剂,一般为中温煤沥青与蒽油或煤焦油混合使用,其软化点为(20±5)℃.     

文摘

炭素回转窑内物料活动层厚度的确定；浸渍压密石油焦基预焙阳极块结构与性能研究；提高大型无隔板镁电解槽用石墨阳极使用寿命途径的探讨；电解铝用石墨阴极的研制；针状焦光学显微结构分析研究……     

氯酸盐电解的铁黑阴极

<正>1 弓言 节电是电解工业的重要研究课题.自采用钛钉金属阳极后,阴极就成为节电研究的主攻方向.气体扩散阴极和非铁活性阴极的研究较常见,前者用氧还原反应替代析氢电极反应’‘’,后者是在基体表面电沉积低氢过电位的Ni合金”-”.本文给出的铁黑阴极是一种新型电极,为电解工业阴极研究开辟了新途径. 在mH—5～6的亚铁盐溶液中,采用电化学手段建立很薄的表面富氧碱区（厚度约20urn）,将原铁阴极表面加工成均匀细颗粒状的黑色表面,称铁黑阴极.该方法简便,材料低廉,可循环再生.本文用电镜图和电子能谱图确定铁黑阴极表面结构和组分.在氯酸盐电解条件下进行析氢极化曲线和90天寿命试验.2 实验 铁黑阴极与原铁阴极的面积相同,约0.scm’.原铁阴极采用氯酸盐电解工业使用的低碳钢材料（福州第一化工厂提供）. 铁黑阴极表面的电镜图（SEM）和X光电子能谱图（XPS）分别在日本S-520扫描电镜仪和英国＊既＊-＊K工电子能谱仪上测试.＊陀图上结合能数值已用C;s内标校正. 测量极化曲线电解液组成为NaCI 1609/din‘和Na。Cr。O,3g/din’,PH—6,温度65士ZC.辅助电极和参比电极分别为钛钉阳极和饱和甘汞电极.阴极电流密度范围为0.1～3.okA/m’. 寿命试验的初始电解液组成与测极化曲线时相同,电液量100cm‘.将原铁阴极     

300 kA铝电解槽电、磁、流多物理场耦合仿真

将标量电位法和磁标量位法相结合,开发了铝电解槽电场、磁场耦合计算模块,并导出了电磁力场以计算磁流体三维湍流流场及其界面波高. 计算结果表明,垂直磁场基本呈现为反对称关系,水平电流对磁流体运动有显著影响,铝液流场形态基本对称,呈现为4个较大漩涡,铝液界面向中部隆起. 将计算结果与测试值进行了比较,表明该方法能够有效用于铝电解槽生产和设计的物理场仿真计算分析.     

Erosion of sintered TiB2-cathodes during cathodic aluminium deposition from LiCl/AlCl3 melts

Using an aluminium dissolution/deposition electrolysis cell, TiB₂, TiB₂/TiC and TiC sintered specimens of different porosity were tested for erosion resistance on exposure to liquid electrodeposited aluminium at 700°C to determine whether cathodes coated with such materials can be applied in aluminium chloride electrolysis cells. Although not wetted by liquid aluminium, the TiC and the TiB₂/TiC composites were extensively eroded. The densest TiB₂ specimens showed the highest resistance against liquid aluminium. The erosion rate of TiB₂ specimens of different density after exposure to the test environment for over 200 h was almost identical and reached a value of 0.16 cm y^–1. The observed wear rates exceed the values predicted on the basis of published solubility data by a factor of approximately 10.     

Peroxide Formation in a Zero-Gap Chlor-Alkali Cell with an Oxygen-Depolarized Cathode

The effects of various factors on the undesired generation of hydrogen peroxide in a zero-gap oxygen-depolarized chlor-alkali cell employing carbon-supported platinum catalysts were studied. The rate of peroxide generation was found to decrease with platinum loading and increase with current density. The quantity of peroxide generated also increased with electrolysis time, and reached a steady state value after a few 100 h of cell operation at 10 kA m⁻². The steady-state peroxide to hydroxide molar ratio was found to increase with brine concentration. This phenomenon is believed to originate from a decrease of water activity at the reaction site that accompanies the brine concentration increase. No correlation between chloride crossover and the concentration of peroxide generated was detected. It is postulated that carbon particles are predominantly responsible for the partial oxygen reduction and that their contribution increases with electrolysis time as a result of processes that render the carbon surface more hydrophilic.     

电解法处理含镍废水的研究

含镍废水不仅造成镍金属的浪费,并且带来环境污染。通过配制硫酸镍溶液模拟含镍废水,采用电解法确定最佳阳极材料为钌涂层钛板,并研究了电解时间、电流强度和Ni~(2+)浓度等因素对Ni~(2+)的回收率的影响。实验结果表明:在电解时间240min,电流强度15A,Ni~(2+)质量浓度20g/L,电解温度50℃,p H值6,搅拌速率300r/min的条件下,Ni~(2+)的回收率为85.42%,电流效率为52.16%。     

Hydrogen consuming anodes for energy saving in sodium sulphate electrolysis

Gas diffusion electrodes, made of PTFE-bonded carbon with precious metal catalysts, were investigated as hydrogen consuming anodes in sodium sulphate electrolysis. The catalysts used were platinum and palladium and mixtures of both metals, prepared by two different methods. Various metal meshes were used as current collector. The electrodes performed well in pure sulphuric acid (5–15 wt-%) and in mixtures with sodium sulphate (10 wt-%) at temperatures of 30 to 70°C and current densities up to 5 kA/m². In long-term experiments, at a current density of 2.6 kA/m², the electrodes were stable over three months. The electrodes were characterised by stationary current density/potential curves and by galvanostatic current interruption measurements.     

石墨化阴极节能特性和发展趋势

对企业自主研发的石墨化阴极技术指标和石墨化阴极在国内外铝电解槽上应用情况进行统计分析,得出结论:石墨化阴极具有良好的导电性、导热性、抗热震性和抗钠侵蚀性,可降低电解铝吨铝电耗,提高电解槽电流强度和电流效率,延长电解槽使用寿命,减少废阴极对环境的污染.同时对石墨化阴极在国内应用存在的问题进行了分析,对石墨化阴极的经济效益和发展前景进行了科学预测.     

Formation of hypochlorite,chlorate and oxygen during NaCl electrolysis from alkaline solutions at an RuO2/TiO2 anode

On-site electrolysis of a weak alkaline solution of NaCl has been applied to an increasing extent for disinfection. To optimize the electrolytic cell and the electrolysis conditions, the current efficiency for hypochlorite, chlorate and oxygen formation at a commercial RuO₂/TiO₂ anode were determined under various conditions. It was found that for solution with low NaCl concentrations, (lower than 200 mol m^?3), and at 298 K, solution flow velocity of 0.075 ms^?1 and high current density, (higher than 2 kA m^?2), hypochlorite formation is determined by mass transfer of chloride. The formation of chlorate in weakly alkaline media at a chlorine and oxygen-evolving anode is ascribed to two reactions, namely, the direct oxidation of chloride to chlorate and the conversion of hypochlorite. This is suggested to split the well-known electrochemical Foerster reaction into a chemical reaction for the conversion of hypochlorite in chlorate and the electrochemical oxidation reaction of water. It is proposed that in an acidic reaction layer at the anode the mechanism of chlorate formation may be given by the following:      

Design, construction and operation of a laboratory scale electrolytic cell for sodium production using a β″-alumina based low-temperature process

Sodium metal can be produced at low temperatures (523 K) by electrolysis of sodium tetrachloroaluminate (NaAlCl₄) in a cell, which employs sodium ion conducting beta-alumina as diaphragm. A laboratory-scale electrolytic cell and associated systems were designed and constructed to study the various aspects of the energy efficient process. Graphite/reticulated vitreous carbon (RVC) was used as the anode and molten sodium as the cathode. Electrolysis was carried out at 523 K with currents in the range 1–10 A (10–125 mA cm^–2). The cathodic current efficiency was close to 100%, but the anodic current efficiency was very low (20–30%), probably due to the consumption of chlorine in the intercalation reaction of graphite and aluminium chloride. The sodium metal was analysed by AAS and found to have 5N purity. On prolonged electrolysis, the graphite anode disintegrated due to the formation of graphite intercalation compounds. RVC behaved as a better chlorine-evolving anode in the initial period of electrolysis, but its ability for chlorine evolution decreased on continuous electrolysis. The study indicated the need for effective stirring of the electrolyte with excess NaCl to avoid build up of aluminium chloride and the resultant complications in the cell.