Effect of TiB_2 content on resistance to sodium penetration of TiB_2/C cathode composites for aluminium electrolysis

1　INTRODUCTIONInrecent years ,therehavebeenincreasingeffortstoimprovetheHall Heroult processintheprimaryaluminiumindustry[1 ] .InordertoovercometheshortagesofHall Heroultprocess ,suchashighconsumptionofelectricalpower ,highconsumptionofcarbonanodeandserious pollutionduetocarbonanodemanufactureandconsumptionetc ,anoveltypeofaluminareducedcellsbasedoninertanodeandwettablecathodesystemwasdevelopedtoreplaceconventionalHall Heroultprocess[2 ,3 ] .Titaniumdiboride(TiB2 )appearstobethebestca…     

Preparation of activated carbons from mesophase pitch and their electrochemical properties

The influences of molar ratio of KOH to C and activated temperature on the pore structure and electrochemical property of porous activated carbon from mesophase pitch activated by KOH were investigated. The surface areas and the pore structures of activated carbons were analyzed by nitrogen adsorption, and the electrochemical properties of the activated carbons were studied using two-electrode capacitors in organic electrolyte. The results indicate that the maximum surface area of 3 190 m2/g is obtained at molar ratio of KOH to C of 5:1, the maximum specific capacitance of 122 F/g is attained at molar ratio of KOH to C of 4:1, and 800 ℃ is the proper temperature to obtain the maximum surface area and capacitance.     

Electrical resistivity of NiFe_2O_4 ceramic and NiFe_2O_4 based cermets

NiFe2O4 ceramic and NiFe2O4 based cermets, expected to be used as the inert anodes in aluminum electrolysis, were prepared and their electrical resistivities were measured at different temperatures. The effects of temperature and composition on their electrical resistivities were investigated. The results indicate that the electrical resistivities of NiFe2O4 based cermets mainly depend on temperature, resistivity of ceramic matrix, composition and dispersion of the metal phase among ceramic matrix. The electrical resistivity of NiFe2O4 ceramic decreases from 10. 094 Ω · cm to 0. 475 Ω · em with increasing temperature from 573 K to 1 233 K. The electrical resistivities of NiFe2O4 based cermets are greatly lowered, but decrease with increasing the temperature with similar trend compared to that of NiFe2O4 ceramic. The resistivities of NiFe2O4 based cermets containing 5 % Ni, 5 % Cu and 5 % CuNi alloy are 0. 046 8, 0.066 8 and 0. 0532 Ω · cm at 1 233 K, respectively, which are all acceptable as inert anode materials compared to that of the current carbon anode used for aluminum electrolysis.     

聚铝沟排布对导流型铝电解槽热应力分布的影响

为了优化导流型铝电解槽聚铝沟设计方案,对槽内热应力分布特征进行研究分析。采用商用有限元计算软件ANSYS针对两种聚铝沟设计方案（即方案Ⅰ为工字型聚铝沟结构;方案Ⅱ为单聚铝沟结构）的导流槽模型进行了电-热-应力耦合计算,同时针对热应力引起的槽体形变进行模拟。结果表明：采用方案Ⅰ工字型聚铝沟结构时,槽体内部热应力较大,尤其是两端靠近横向聚铝沟的阴极炭块内部具有较大的应力集中,而采用方案Ⅱ单聚铝沟结构时,该处的应力集中得到了较好的缓和,槽体形变较小。     

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。     

La(Ⅲ)改性沸石脱除模拟硫酸锌溶液中氟离子的热力学和动力学（英文）

为了明确La(Ⅲ)改性沸石脱除模拟硫酸锌溶液中氟离子的机理,利用XRD、SEM和EDX对吸附剂进行表征,研究吸附剂用量和吸附时间对吸附过程的影响,采用吸附等温线与吸附动力学对吸附过程进行探究。结果表明,Langmuir吸附等温线模型更适合吸附过程;在303和313 K条件下,吸附剂的最大理论吸附容量分别为20.83和23.04 mg/g;Temkin和D-R吸附等温线模型证明氟离子脱除过程为物理吸附,且吸附过程遵从准二级动力学模型;同时,热力学计算结果(?G~Θ0 k J/mol,?H~Θ=8.28 k J/mol,?S~Θ=0.030 k J/(mol?K))说明La(Ⅲ)改性沸石脱除模拟硫酸锌溶液中氟离子是自发、吸热的物理过程;将La(Ⅲ)改性沸石应用在工业硫酸锌溶液中,用量为15 g/L时,氟离子浓度从98.05 mg/L降低至44.09 mg/L。     

光电化学冶金提取半导体元素——以碲为例

针对电化学冶金提取半导体元素存在的问题,提出采用光电化学冶金的方法来进行半导体元素的电化学沉积提取。结合半导体特性以及光电化学基本理论,阐述光电化学冶金的优势,并以碲提取为例验证光电化学冶金的优越性。结果表明:光电化学沉积过程中,半导体沉积物吸收能量大于其自身带隙宽度的光子后受激发产生光生电子-空穴对,光生电子从半导体流向电解液促进电化学还原,同时光生载流子可减小电阻率和能带弯曲,降低工作电极所分摊的电势差。与常规的电化学沉积相比,光电化学沉积可以强化电极过程、降低槽电压,以及提高沉积速率、电流效率和产能,具有良好的应用前景。最后指出光电化学冶金未来发展可能面临的问题,并对其内涵进行拓展。     

基于非线性浅水模型的铝电解磁流体动力学计算

基于铝电解槽内流体体系及电磁场分布特点,建立了非线性磁流体动力学浅水模型,并应用此模型对某300 kA电解槽的熔体流场及铝液-电解质界面波动进行瞬态数值研究.在此基础上,通过动力学计算分析极距及铝液区垂直磁场对磁流体稳定性的影响.结果表明:随着极距的减小,界面波动由稳定趋向于不稳定;减小铝液区的垂直磁感应强度能大幅提高磁流体的稳定性.     

Zn靶与掺铝ZnO靶共溅射制备ZnO:Al薄膜及其性能

采用Zn靶和ZnO(掺2%Al2O3(质量分数))陶瓷靶在玻璃衬底上共溅射沉积Al掺杂ZnO薄膜,即ZnO:Al透明导电薄膜,研究Zn靶溅射功率(0～90 W)和衬底温度(室温、100℃和200℃)对薄膜结构、形貌、光学和电学性能的影响。结果表明:按双靶共溅射工艺制备的ZnO:Al薄膜的晶体结构均为六角纤锌矿结构,且随着Zn靶溅射功率的增加,薄膜的结晶质量呈现出先改善后变差的规律,薄膜中的载流子浓度逐渐升高,电阻率逐渐降低,而薄膜的光学性能受其影响不大;随着衬底温度的升高,薄膜的结晶性能得到改善,薄膜的可见光透过率增强,电阻率降低。     

铝电解槽异型阴极钢棒的对比仿真研究

减小铝液中水平电流是实现铝电解槽节能降耗的重要手段之一.本文针对当前出现的五种有代表性的异型阴极钢棒,在有限元商业软件ANSYS平台上分别建立其相应的三维电热场耦合切片计算模型,在兼顾槽底压降变化等因素的情况下,分析和对比了这些钢棒在减小铝液中水平电流方面的效果.结果表明:相比于传统阴极钢棒,五种异型阴极钢棒都能不同程度地战小铝液中的水平电流,但除方案二的阴极钢棒外,都在一定程度上增大了阴极压降;同时阴极发块和钢棒的电流密度也都有所改变.