320kA预焙铝电解槽电磁场分布计算与优化

利用ANSYS电磁场有限元法,建立了320 kA预焙铝电解槽三维电磁场有限元模型,计算了铝电解槽内的电场分布及磁场分布,计算结果与实测结果相吻合,验证了该模型的正确性.在此基础上提出了一种新型电解槽结构,并应用参数化设计语言(APDL)建立该结构的电磁场计算模型,以磁场为目标对该结构进行了整体优化.最终优化后电磁场分布表明:该结构铝电解槽能减小铝液层水平电流,磁场分布对称性好,有利于改善槽内铝液的流动状态,具备较大的节能潜力.     

铝电解预焙阳极沥青烟净化技术研究进展

随着我国经济建设的高速发展,建筑行业和日化产业都得到了长足的发展,带动之下,电解铝行业也发展迅速,这也在某种程度上推动了炭素企业的快速发展。但同时一些问题也随之尖锐化,诸如沥青烟的排放,一直是企业和国家相关部门亟待解决的问题。本文对沥青烟的构成和国内外对沥青烟的净化技术进行了阐述,从而对铝电解预焙阳极沥青烟净化技术的发展做了技术性展望,以期能够对国内这一技术的发展有所助益。     

铝电解槽熔体中电流分布的数值计算

在电解槽三维电位场计算的基础上,对电解槽在不同工艺条件下及不同结构时的电流场进行了数值计算:1)伸腿长度为零的理想情况;2)伸腿伸至阳极底部;3)不同铝水平及换极;4)泄流式电解槽.通过分析发现,铝液中y 向电流密度沿阴极长度方向表现出先增后降的趋势,Jy的幅值随铝液层面降低有所增加.在伸腿伸至阳极底部时,在槽边部会出现较大的逆向电流,伸腿越长,逆向水平电流越大.铝液层面中垂直电流密度沿阴极碳块长度方向自里向外呈现增加趋势,且铝液层面越低,电流密度变化梯度越大.铝液中x向电流可以忽略,且随铝水平变化较小.泄流式电解槽熔体中存在较大的电流密度集中现象,炉底压降相对较大.     

预焙阳极中微量元素的控制与生产实践

本文分析预焙阳极中微量元素的控制和生产实践,阐明预焙阳极中微量元素的来源和主要影响,并对微量元素的控制方法进行总结,用以提高预焙阳极生产质量,供相关人员借鉴参考。     

不同开槽阳极铝电解槽的节能性研究

基于有限体积方法,建立三维传统阳极、纵向开槽和横向开槽阳极铝电解槽非稳态数学模型,采用磁动力流体模型(MHD)中电势法计算电磁场,把电磁力作为动量方程的源项,通过流体体积函数(VOF)法追踪电解质-铝液界面的波动,用离散相模型(DPM)追踪气泡的运动路径.对比分析传统阳极、纵向开槽和横向开槽阳极铝电解槽中电解质-铝液界面波动和气泡分布情况.结果表明,纵向开槽阳极下电解质-铝液界面波动幅度小于横向开槽阳极下的电解质-铝液界面波动幅度,且都小于传统阳极下电解质-铝液界面波动幅度.纵向开槽阳极底部的气体体积分数最小.     

浅析160 kA预焙电解槽阳极效应系数控制

通过对贵铝二期160kA预焙电解槽阳极效碰系数的分析与讨论，发现AE系数与Al2O3浓度，计算机控制加工制度、原材料质量以及人工操作控制等因素有关。降低AE系数，有利于提高经济技术指标。提出了今后效应系数的控制发展方向。     

钢中铝夹杂物原位统计分布分析的判据方法

应用金属原位分析仪对含铝夹杂物的参考物样品进行分析,得出铝夹杂物单次火花强度信号分布规律。采用迭代法确定夹杂物定量分析的重要参数——阈值,提出钢中铝夹杂物定量分析新方法,结合化学相分析结果以及金相检测结果最终得到参考物样品中铝夹杂物的含量与火花频数的数学模型。把该数学模型应用到实际钢铁材料中,测得结果与ICP-AES法分析结果一致。     

Loss of current efficiency in aluminum electrolysis cells

Consideration of the mechanism of loss of current efficiency (CE) leads to a form of equation which is simple, likely to give reasonable extrapolation beyond the range where experimental data are available, and convenient for responding to practical questions. With coefficients generated from plant experiments (performed by others), the equation is log (pct loss of efficiency) = 0.0095 (superheat) -−0.019 (pct A1F₂) − 0.060 (pct LiF) + const where superheat is the difference (in °C) between cell temperature and the pseudo-binary eutectic temperature with A1₂O₃, and pct A1F₃ is excess A1F₃. The coefficient for CaF₂ is zero. The constant is characteristic of the cell design. The question of reconciling the values of the coefficients with literature data on the solubility of Al in cryolite melts and current theories of loss of efficiency is discussed. Formerly Principal Scientist, Kingston Laboratory, Alcan International Ltd., Kingston, ON K7L 5L9, Canada, is retired.     

铝电解槽阳极气泡行为研究

利用透明槽研究铝电解槽阳极气体行为.研究表明：阳极气体的生成是一个连续的过程,阳极侧部生成的气泡比阳极底部生成的气泡小.正对阴极的阳极表面生产的气泡比其它阳极部位上生成的气泡小,这是一个明显的现象.而且,正对阴极的阳极表面生成的气泡不会汇集成大气泡,这和其它阳极部位生成的气泡有很大的差异.阳极底部生成的气泡全部从阴阳极中间的电解质移动溢出电解质.阳极气泡的大小影响槽电压,气泡直径增大3 mm,槽电压增加0.21 V.同时,电流密度为0.5 A/cm2底部阳极气体离开阳极时槽电压的变化为0.16 V.电流密度为0.3 A/cm2,底部阳极气体离开阳极时槽电压的变化为0.12 V.     

预焙阳极铝电解节能降耗途径探讨

本文以85kA预焙槽为例，从铝电解槽生产成本的构成着眼，探讨了从优化工艺技术条件、强化电流强度、降低原材料消耗、燃料及动力消耗、制造费用等方面降低预焙铝电解生产成本的途径，电流强度的强化、优化工艺技术条件、阳极加高等技术的成功应用，提高了电流效率、降低了直流电耗，节能效果显著，创造了良好的经济效益。     

Quality of anode mass in aluminum electrolysis technology with the Soderberg anode

The properties and quality of the anode mass produced at RUSAL Krasnoyarsk for a prolonged period after switching the Soderberg anode technology from “thick” and “dry” anode mass to the pilot production of a “colloid” mass with a lowered pitch content are analyzed.     

Monitoring of the quality of a soderberg anode for aluminum electrolyzer with the upper current lead

By sampling the cores from the Soderberg anodes of switched-off aluminum electrolyzers, the distribution of the physical properties over the anode height, including during a variation in temperature, is studied. An analysis is given for the dynamics of the variation in the quality of anodes from 1993 to 2006. It is shown that the physical properties of the Soderberg anode approach the requirements made for burnt anodes.     

中低合金钢中铝夹杂物的原位统计分布分析

采用原位统计分布分析技术测定钢中铝夹杂物时,测定结果不仅受异常火花频数影响,还受异常火花强度影响,据此建立了一种新的计算钢中铝夹杂物的数学模型。该数学模型与单由异常火花频数建立的数学模型相比,计算结果更准确。用于碳素钢和中低合金钢标样中铝夹杂物的测定,测定值与认定值吻合较好,相对标准偏差为7.31%~15.11%(n=11)。     

Effect of baking temperature and anode current density on anode carbon consumption

The electrolytic anode carbon consumption (CC) was studied as a function of anode baking temperature (BT) and anode current density in a closed laboratory cell, where the anode gas was absorbed and also monitored on a CO/CO₂ analyzer. The CC referred to Faraday’s law was determined from the weight loss of the anode, the carbon gasification (CG) from the amount of absorbed anode gas, and the formation of carbon dust (CD) by the difference. The CC decreased by about 9 pct per 100 °C increase in BT, and it increased with decreasing anode current density, particularly at low current densities. The CG and CD showed similar trends. The excess CG, which was attributed to the Boudouard reaction (CO₂ + C = 2CO), showed a relative decrease with increasing current density, although the overall rate of the reaction increased.     

The influence of the atmosphere on the sintering of aluminum

Alloys of Al, Al-0.15Mg, and Al-12Sn made using air atomized aluminum powder and pressed to green densities of 75 to 98 pct were sintered under argon or nitrogen. Sintering in argon is only effective at high green densities when magnesium is present. In contrast, highly porous aluminum can be sintered in nitrogen without the need for magnesium. The oxygen concentration in the gas is reduced by the aluminum through a self-gettering process. The outer layers of the porous powder compact serve as a getter for the inner layers such that the oxygen partial pressure is reduced deep within the pore network. Aluminum nitride then forms, either by direct reaction with the metal or by reduction of the oxide layer, and sintering follows.     

On the mechanism of the anode effect in aluminum electrolysis

The dependency of the critical current density in aluminum electrolysis on the bulk concentration of alumina has been reported in various forms. Some workers found different relationships in restricted ranges of the alumina content and concluded on possible changes of the reaction mechanisms and various types of anode effect. A previously developed mathematical model could show that the anode effect is initiated as the actual current density equals the limiting one. The model is now applied to check some of the available theories. Comparison with experimental data shows that the varying effect of the alumina concentration can be described by a single relationship taking account of the combined action of mass transfer, fluid dynamics of gas release, and wettability for all values of the alumina content. The results suggest that there is every reason for the view that only one process occurs. A distinction of various types of mechanisms provoking the anode effect is unnecessary.     

Determination of metal inventory and current efficiency in commercial aluminum reduction cells

A method for the determination of the metal inventory in commercial aluminum reduction cells, based on radioisotope dilution, has been developed, employing a¹⁹⁸Au tracer. By taking a large number of samples from the cells, the current efficiency is evaluated from the slope of the cumulative metal inventory vs time data. The method allows a determination of the current efficiency over a period of 2 to 3 days with a relative precision of approximately 1 pct. The paper gives a thorough discussion of the sources of error inherent in the procedure suggested. Formerly Research Associate at the same University.     

The diet and gut microflora influence the distribution of enteroendocrine cells in the rat intestine

Several functions of the gut are locally influenced by peptides and biogenic amines released from enteroendocrine cells. The aim of the present study was to assess whether the luminal stimulus of diet or microbial flora or diet-microbial interactions have an influence on the distribution of enteroendocrine cells along the crypt-surface axes of the small and large intestine. The effects of diet and indigenous flora were investigated by comparing the numbers of argyrophil and serotonin immunoreactive cells in the jejunum and colon of germ free and conventional rats fed either a purified diet containing fine ingredients or a commercial diet containing crude fibre of cereal origin. The effect of human flora were analysed in germ-free rats inoculated with human faecal organisms. 1. Feeding the commercial diet reduced the number of argyrophil endocrine cells in the jejunum and serotonin immunoreactive cells in the colon of germ-free animals but increased the serotonin immunoreactive cells in the colon of conventional animals. 2. The rat flora increased the serotonin immunoreactive cells in the colon of animals fed a commercial diet and decreased in those fed a purified diet. 3. Inoculation of human flora increased the numbers of serotonin immunoreactive cells both in the jejunum and colon. The results provide evidence that the dietary changes and diet-microbial interactions can affect the regional number of enteroendocrine cells.