断电流法测阳极过电位的模拟及其遗传算法优化

利用断电流法测定铝电解阳极电电位，用拟牛顿法确定过电位衰减极化曲线方程中的各项参数，结果表明采用拟牛地往往使得曲线的模拟结果与实验结果有一定偏差，从而影响其其预测功能，采用实数编码方法，把遗传算法应用于电位衰减曲线方程中的参数辨识，通过在遗传进化过程中动态改变交叉率和变异率以增加其全局寻优的机会，结果表明模拟曲线和实验结果相符很好。     

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。     

阳极过量消耗对铝电解电耗的影响

本文介绍阳极过量消耗、阳极净消耗以及阳极过量消耗与电流效率和电耗关系的理论。工业试验表明，当阳极过量消耗分别降低１８和２１ｋｇ／ｔＡｌ时，电流效率分别提高０．５％和１．４％，电耗分别降低３７７．９和４６６．１ｋＷｈ／ｔＡｌ。降低阳极过量消耗不仅降低铝电解原料成本，而且是降低铝电解电耗的另一个重要途径。     

降低炭阳极消耗对铝厂经济效益的影响

本文不但从理论上,说明降低铝用炭阳极消耗会提高电流效率、增加铝产量和降低电耗,而且列举国内外的实例证明上述理论。     

铝电解用碳素阳极添加剂的有效添加法—浸渍法

先期实验已发现Na_2CO_3作为添加剂能使阳极过电位下降0.1伏。但把Na_2CO_3混在阳极料中一起成型的添加方法欠妥。本文报告了一种更有效的方法——浸渍法。使用这种方法后,石墨阳极上阳极过电位在电解中可下降0.2伏,碳素阳极上过电位可下降0.1伏左右。如果在工业上实现,那么可使吨铝能耗下降300～600KW.h.     

阳极糊质量对铝电解生产的影响

阐述了在自焙铝电解槽生产中，因阳极糊质量问题，而使电解铝正常生产遭到破坏，针对产生的现象及危害，分析其机理，采取了相应的处理办法，把造成的损失降低到最低限度。     

焙烧参数对阳极质量的影响

在介绍参考文献实验结果的同时,结合笔者在实际生产中的工作经验,阐述了阳极焙烧参数,如升温梯度、最终焙烧温度及焙烧时间对阳极质量的影响。论述了火道设计和焙烧炉使用状态的重要性及焙烧过程控制的影响。     

AlF3添加剂对氧化铝粉体微观结构的影响

在醇盐水解法制备a-Al2O3工艺过程中引入AlF3作为添加剂,通过XRD、SEM研究了AlF3加入量、水热条件、热处理温度对产物晶相及微观形貌的影响.研究结果表明:AlF3加入可使α-Al2O3相在800℃至900℃之间形成;相同水热温度下,随AlF3加入量增大,α-Al2O3的微观形貌是从不规则的板状结构向嵌入式六角板状结构发展;随水热温度升高,αa-Al2O3的微观形貌则由多面体结构向六角板状结构再到"蠕虫状"结构转变.     

LiF对Na_3AlF_6-K_3AlF_6-AlF_3熔体初晶温度和Al_2O_3溶解度的影响

采用步冷曲线法测定Na3AlF6-K3AlF6-AlF3-LiF熔体的初晶温度,采用旋转刚玉片质量损失法测定Al2O3在Na3AlF6-K3AlF6-AlF3-LiF熔体中的溶解度。结果表明:当LiF添加量在0～4%范围内时,每添加1%LiF使Na3AlF6-K3AlF6-AlF3熔体的初晶温度降低3～4.7℃,小于Na3AlF6-AlF3熔体中添加LiF后初晶温度的影响;在0～3%的范围内,每添加1%LiF将使Al2O3在Na3AlF6-K3AlF6-AlF3熔体中的溶解度降低0.23%～0.55%。     

焙烧参数对预焙阳极特性影响的实验研究

搭建了实验平台,采用实验的方法研究了升温速率和终焙温度对预焙阳极体积密度、气孔率、电阻率和挥发分析出率等参数的影响。结果表明,气孔率、电阻率和挥发分析出率都随升温速率的增大而增大,在升温速率较小时,体积密度随升温速率的增大快速减小,当升温速率超过80℃/h后,再增大升温速率,体积密度变化不大。体积密度、气孔率和挥发物析出率都随终焙温度的升高而升高,而电阻率则随终焙温度的升高而降低。     

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.     

Coupled heat/mass-balance model for analyzing correlation between excess AlF3 concentration and aluminum electrolyte temperature

The influence of aluminum electrolyte component on its temperature is an important issue within the field of aluminum reduction with pre-baked cells. The characteristic correlation between excess AlF3 concentration and aluminum electrolyte temperature was explored through the modeling of heat and mass transfer processes in industrial pre-baked aluminum reduction cells. A coupled heat/mass-balance model was derived theoretically from the mass and energy balance of an electrolysis cell, and then was simplified properly into a practical expression. The model demonstrates that if environmental temperature and Al2O3 concentration keep constant, the excess AlF3 concentration decreases with the aluminum electrolyte temperature linearly and its decrease rate is dependent on the heat transfer property of aluminum electrolyte, side wall and cell shell. Secondly, experiments were conducted on site with two industrial cells in an aluminum electrolysis plant. Excess AlF3 concentration and aluminum electrolyte temperature were obtained simultaneously together with other parameters such as Al2O3, CaF2, MgF2 and LiF concentrations. Results show that the maximum absolute error between the tested value and the calculated value of excess AlF3 concentration using the proposed model is less than 2%. This reveals that the coupled heat/mass-balance model can appropriately characterize the correlation between excess AlF3 concentration and aluminum electrolyte temperature with good accuracy and practicability.     

预焙槽焦粒焙烧启动工艺的实践及探讨

电解槽焙烧启动是电解铝生产的重要阶段,焙烧启动的工艺与技术水平直接关系到电解槽的生产管理和技术经济指标。通过焦粒焙烧启动工艺实践,从装炉到后期管理各环节的研究分析,提出了一些优化措施。     

Determination of ohmic/voltage drop and factors influencing anodic overvoltage of carbon anodes in Na_3AlF_6-Al_2O_3 based melts

1　INTRODUCTIONAlthoughtheanodicprocessandmeasurementofanodicovervoltageincryolite aluminameltshavebeenthesubjectsofnumerousinvestigations ,problemssuchasthereactionmechanismandtherate deter miningstepoftheanodereactionarestillcontrover sialandneedclarification .Theexperimentalinforma tionischaracterisedbymajordivergenceregardingthemagnitudeandthetypeofanodicovervoltage ,whichismostlikelycausedbythefollowingfac tors[16 ] :1)Theanodicovervoltagediffersamongtheva rietyofcarbonmaterials,sucha…     

Industrial testing of property-modified prebaked carbon anode for aluminum electrolysis

1　INTRODUCTIONInaluminumelectrolysis process ,thequantitygradeofcarbonanoderestrictsnotonlytheimprove mentofproductiontechniques ,butalsotheadvance mentofproductiontargets.Formany years ,largenumberofresearchesweredonetoimprovethephysi cal,chemicalandelectrochemicalperformanceoftheanodeinordertoenhancecurrentefficiency ,reduceenergyconsumption ,decrease productioncostandcleancircumstanceofaluminum plantanditssur roundingarea .Recently ,manylaboratoryresearchresultsweresuccessfullyappliedf…     

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.     

钾冰晶石低温电解质研究现状

综述了钾冰晶石低温电解质体系物理化学性质、低温电解等方面的研究现状,对该低温电解质体系存在的问题进行了分析,并展望了其未来的研究方向.