导流型铝电解槽用复合硼化钛阴极制备方法

导流型铝电解槽用复合硼化钛阴极制备方法。本发明在用振动成型TiB2阴极碳块砌筑好的导流型铝电解槽的阴极内衬上，涂覆多层不同TiB2含量的碳胶TiB2涂层浆料，利用铝电解焦粉焙烧工艺产生的热量炭化涂层，在线制备导流型铝电解槽用金属铝液可润湿性TiB2阴极。本发明提高了导流型铝电解槽可润湿性阴极的服务寿命，所生产的产品成本较低，并能完全与金属铝液润湿，符合导流型铝电解槽的要求，可以达到节能的目的。在线制备可润湿性梯度功能复合TiB2阴极，不需另外添加设备，施工费用低，应用方便。     

槽型对5kA级惰性阳极铝电解槽流场影响仿真

提出了两种5 kA级惰性阳极铝电解槽结构,使用有限元仿真方法计算了不同槽型电解槽在仅电磁力作用、仅阳极气体作用、电磁力和阳极气体共同作用下的流场和界面波动情况。计算结果表明:铝液运动主要受电磁力控制,电解质运动主要受阳极气体控制;槽型1比槽型2整体流速更低,界面波动更小。     

电解槽内异型凸台对电解质/铝液界面波动的影响

针对铝电解槽内电解质/铝液界面的波动现象,基于计算流体动力学(CFD)的方法建立了铝电解槽内电解质/铝液两相流体流动的数学模型.使用Fluent软件的流体体积自由面跟踪法和自定义函数,研究了阴极凸台对电解质/铝液界面波动的影响.结果表明,异型凸台的加入使得两相界面的波动幅度降低了17.2%,但凸台的存在同时也使得熔体对侧部槽帮冲刷增强.     

5kA级惰性阳极铝电解槽流场仿真研究

针对铝电解槽流场计算方法的不足,率先提出一种用于铝电解槽流场仿真计算的间接耦合方法,并使用此方法对5 kA级惰性阳极铝电解槽分别在电磁力、阳极气体、电磁力和阳极气体共同作用下的电解质和铝液流场分布情况进行了仿真计算。计算表明,计算方法能够合理计算出电解质和铝液在任一体积力作用下的流场分布。5 kA级惰性阳极铝电解槽电解质流动主要受阳极气体控制,铝液流动主要受电磁力控制。电解质在仅电磁力作用、仅阳极气体作用、电磁力和阳极气体共同作用下的平均流速分别为1.784 cm/s、3.657 cm/s、3.814 cm/s,铝液平均流速分别为1.295 cm/s、3.509 cm/s、3.696 cm/s。     

300kA新式异型阴极双钢棒铝电解槽生产实践

300kA新式异型阴极双钢棒铝电解槽可有效减缓铝液的流动、大幅降低铝液水平电流、降低铝液和电解质界面变形的波形幅度、提高电解槽的稳定性、降低电解槽的工作极距,同时使槽侧部由原来的散热型改为保温型来维持电解槽的热平衡。在保证电解槽平稳高效生产的前提下,电流效率比普通异型阴极电解槽高1个百分点以上,吨铝直流电耗降低400kWh。     

导流型铝电解槽用复合硼化钛阴极制备方法

本发明在用振动成型Ti段阴极碳块砌筑好的导流型铝电解槽的阴极内衬上，涂覆多层不同TiB2含量的碳胶TiB2涂层浆料，利用铝电解焦粉焙烧工艺产生的热量炭化涂层，在线制备导流型铝电解槽用金属铝液可润湿性TiB2阴极。     

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.     

168kA新型阴极高效节能铝电解槽磁流体运动的数值模拟

建立了168 kA新型阴极铝电解槽磁流体运动的数学模型,对电解质与铝液交界面的流场、电解质的流场以及阴极铝液的流场进行了模拟,并对新型阴极电解槽阳极导杆等距电压降进行了测量。研究结果表明：新型阴极铝电解槽可隔断槽内铝液流动,降低槽内阴极铝液的流速。新型阴极铝电解槽铝液与电解质交界面的速度矢量和较普通阴极铝电解槽铝液与电解质交界面的速度矢量和低2～3倍,且极值分布更为均匀。新型阴极电解槽内铝液与电解质界面处的磁流体速度最大,然后以界面为中心线逐渐减小。     

500 kA铝电解槽新式节能阴极结构技术的应用研究

本研究将新式节能阴极结构技术应用于某铝厂500kA铝电解槽,通过电解槽电热平衡仿真模拟,设计保温型内衬结构,成功减少了铝液中水平电流,并降低了电解槽阴极电压降。与传统铝电解槽相比,节能降耗效果显著。     

铝电解槽电磁流强耦合仿真及其在新型阴极上的应用

已在工业应用的各新型阴极结构铝电解槽的电磁流场行为仍未完全明晰.论文首先在ANSYS平台上建立铝电解槽瞬态三维三相磁流体模型,并应用该模型对采用3种新型阴极结构的某420 kA槽开展电磁流场强耦合计算.结果表明,相较于普通阴极,3种新型阴极方案均可使槽内铝液、电解质流速下降,其中,凸台型阴极对应的电解质流速降幅较大,不利于氧化铝颗粒的熔解和扩散;在降低铝液-电解质界面波动方面,3种方案均有一定程度的效果,凸台型结构可使得界面大变形面积减小;此外,在电流效率上,应用凸台型阴极结构将使电流效率略微降低.该模型可为大型铝电解槽结构方案的选型提供基础工具.      

Simulation of Magnetohydrodynamic Multiphase Flow Phenomena and Interface Fluctuation in Aluminum Electrolytic Cell with Innovative Cathode

A three-dimensional (3D) transient mathematical model has been developed to understand the effect of innovative cathode on molten cryolite (bath)/molten aluminum (metal) interface fluctuation as well as energy-saving mechanism in aluminum electrolytic cell with innovative cathode. Based on the finite element method, the steady charge conservation law, Ohm’s law, and steady-state Maxwell’s equations were solved in order to investigate electric current field, magnetic field, and electromagnetic force (EMF) field. Then, an inhomogeneous multiphase flow model of three phases including bath, metal, and gas bubbles, based on the finite volume method, was implemented using the Euler/Euler approach to investigate melt motion and bath/metal interface fluctuation. EMF was incorporated into the momentum equations of bath and metal as a source term. Additionally, the interphase drag force was employed to consider different phase interactions. Thus, present work owns three main features: (1) magnetohydrodynamic multiphase flow are demonstrated in detail both in aluminum electrolytic cell with traditional cathode and innovative cathode; (2) bath/metal interface fluctuation due to different driving forces of gas bubbles, EMF, and the combined effect of the two driving forces is investigated, which is critical to the energy saving; and (3) the effect of innovative cathode on melt flow and motion of gas bubbles. A good agreement between the predicated results and measurement is obtained. The velocity difference leading to the melt oscillation decreases due to more uniform flow field. The average velocity of metal in the cell with innovative cathode decreases by approximately 33.98 pct. The gas bubbles in the cell with innovative cathode releases more quickly under the effect of protrusion on the cathode. The average bubble release frequency increases from 1.1 to 1.98 Hz. Hence, the voltage drop caused by gas bubbles would decrease significantly. In addition, the two large vortices are broken into many small vortices due to the protrusion. The final disappearance of the small vortices as a result of viscous dissipation is conducive to the suppression of bath/metal interface fluctuation. The average interface amplitude in the cell with innovative cathode reduces to 75.95 pct of that in the cell with traditional cathode.     

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.     

静磁场控制板坯连铸结晶器液面波动

 用Pb Sn Bi低熔点合金进行了热模拟实验,研究了在静磁场作用下板坯连铸结晶器内的液面波动行为。实验结果表明可应用静磁场控制结晶器内金属液面的波动,且磁场对表面波动的抑制作用有一最佳值,即磁感应强度为05 T时液面平均波动最小。为此,为了减少由于液面波动引起的连铸板坯中的卷渣缺陷,有必要在一定的浇铸条件下优化磁感应强度。吹入氩气加剧了表面波动,且随着氩气流量的增加扰动加大。施加电磁制动能够使吹入氩气引起的液面波动受到显著的抑制。     

电磁搅拌对特大方坯结晶器内流场及温度场影响

以某厂断面为410 mm × 530 mm的特大方坯结晶器为原型,利用ANSYS有限元软件建立三维数值模型,研究电磁搅拌对结晶器流场及温度场的影响。施加电磁搅拌后,钢液受到径向电磁力,液面呈现旋转流动趋势。结晶器内钢液最大切向速度随着电流的增加而增大,随着频率的增加而减小。电磁搅拌的电流大小由0 增加到500 A时,液面波动由1.21 mm增加到4.35 mm。电磁搅拌能够使钢水的高温区局限于连铸结晶器上部,钢水温度更加均匀。同时钢液的水平旋流能够抑制初生坯壳的生长,降低坯壳的生长速度,使结晶器出口处坯壳厚度变薄。综合分析,该厂在实际生产时合理的电磁搅拌的电流大小应为400 A,频率为1.5 Hz,此时钢渣液面波动约为2.73 mm,温度场较为均匀。      

电磁场作用下板坯连铸结晶器内的弯月面行为

用Pb-Sn-Bi低熔点合金进行了热模拟实验.从液面波动人手,研究了在单条形电磁场作用下板坯连铸结晶器内的弯月面行为.实验结果表明可应用磁场控制结晶器内金属液面的波动.当水口角度为向下30°时,磁场对表面波动的抑制作用有一最佳值,即磁感应强度为0.5 T时液面平均波动最小,液面较稳定.施加磁场使弯月面处温度明显提高,使水口出流的向下冲击深度受到抑制,这有利于夹杂物的上浮分离,达到提高板坯内部质量的目的.     

330 kA铝电解槽异形阴极碳块对水平电流的影响

采用有限元仿真计算,对330 kA铝电解槽进行传统阴极碳块结构和异形阴极碳块结构的电场进行仿真模拟,主要对铝液中水平电流分布进行分析。研究发现,异形阴极碳块结构相对于传统阴极碳块结构能够在影响压降较小的前提下降低水平电流密度。模拟结果表明,在异形阴极碳块表面凸起中增加隔断并改变凸起角度,对降低铝液中水平电流效果明显,能够降低铝液中最大水平电流密度27.8%,平均水平电流密度34.3%,有效提升了铝电解槽电流效率。     

电磁搅拌作用下水口深度对液面波动的影响

 结晶器内液面波动会影响连铸坯的质量,施加电磁搅拌使钢液的液面呈旋转抛物面。电磁搅拌电流过大或拉速过高会造成保护渣卷渣现象,对铸坯质量造成不利的影响。以某钢厂[?]250 mm连铸圆坯结晶器电磁搅拌为研究对象,采用电磁-流体单相耦合的方式及流体体积函数VOF模型,建立描述结晶器电磁搅拌作用下液面波动的数学模型,研究电磁搅拌作用下浸入式水口深度对液面波动的影响。研究表明,通过增大水口深度,能够改善因电磁搅拌强度过大或拉速过大造成的卷渣现象,减小水口附近的液面波动。     

GCr15钢大方坯结晶器电磁搅拌工艺参数优化研究

摘要：为明确不同电磁搅拌条件对结晶器内钢液流动、传热行为的影响规律,对现场大方坯连铸结晶器电磁搅拌工艺参数的配置提供依据,采用ANSYS Fluent及Maxwell研究了320mm×280mm断面GCr15高碳轴承钢连铸过程中结晶器电磁搅拌工艺参数对结晶器内钢液温度场、磁场特性、注流冲击深度及液面波动的影响规律。研究结果表明,在M-EMS作用下,结晶器内钢液温度的耗散明显优于无电磁场作用工况,有利于改善结晶器内温度均匀性。注流的冲击深度随电流强度的增大而降低,而频率改变对钢液冲击深度影响不明显。当电磁搅拌电流强度一定时,随着搅拌频率增加,液面波动趋于平缓;当搅拌频率一定时,随着电流强度增加,液面波动变剧烈。对于320mm×280mm断面GCr15高碳轴承钢不同工艺进行工业试验,只改变结晶器电磁搅拌参数,从300A/2Hz调整到350A/3Hz,铸坯横截面中心碳偏析指数从1.06降低到1.01,铸坯纵截面中心碳偏析指数的平均值从0.98升至0.99,适合该钢种结晶器电磁搅拌工艺参数为350A/3Hz。     

Application of Electromagnetic (EM) Separation Technology to Metal Refining Processes: A Review

Application of electromagnetic (EM) force to metal processing has been considered as an emerging technology for the production of clean metals and other advanced materials. In the current paper, the principle of EM separation was introduced and several schemes of imposing EM field, such as DC electric field with a crossed steady magnetic field, AC electric field, AC magnetic field, and traveling magnetic field were reviewed. The force around a single particle or multi-particles and their trajectories in the conductive liquid under EM field were discussed. Applications of EM technique to the purification of different liquid metals such as aluminum, zinc, magnesium, silicon, copper, and steel were summarized. Effects of EM processing parameters, such as the frequency of imposed field, imposed magnetic flux density, processing time, particle size, and the EM unit size on the EM purification efficiency were discussed. Experimental and theoretical investigations have showed that the separation efficiency of inclusions from the molten aluminum using EM purification could as high as over 90 pct. Meanwhile, the EM purification was also applied to separate intermetallic compounds from metal melt, such as α-AlFeMnSi-phase from the molten aluminum. And then the potential industrial application of EM technique was proposed.