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Aluminum industry depends on coal-tar-pitch as a binder to produce carbon anodes used for aluminum electrolysis. This binder is nonrenewable and mainly composed of polycyclic aromatic hydrocarbons ...

China is short of high grade bauxite for the production of smelting grade alumina. With the massive exploitation of potassium containing bauxite in China, the produced Bayer alumina contains a non-negligible content of potassium oxide. When this kinde of alumina is used as the raw material for aluminum electrolysis, the potassium would cause multiple effects to the cell performance. In this paper, the potassium concentrations of fresh alumina, secondary alumina, aluminum fluoride, anode, electrolyte, anode cover, cathode block, carbon lining, silicon carbide block and product aluminum et al. in 160 kA and 200 kA prebaked aluminum reduction cells were tested and a potassium balance model was preliminarily given. Initial results showed that most of the potassium was brought into the cell by the potassium containing impurities in the fresh alumina. The only effective way for potassium removal from the cell was through the carbon residue though nearly 80 wt% of the potassium would stay and enrich in different positions of the cell.

High temperature oxidation and corrosion behaviours of Ni–Fe–Cr alloys with different Cr contents (Cr = 0, 10, 15 wt.%) were investigated as inert anodes for aluminum electrolysis. Oxidation results at 960 °C in air showed that Ni–Fe–15Cr alloy formed a tri-layer oxide structure with an outer layer of (Ni,Fe) 3 O 4 spinel, a middle layer of (Ni,Fe,Cr) 3 O 4 spinel and an oxidation resistant inner layer of Cr 2 O 3 . Simultaneously, the tri-layer oxide scale exhibited good electrical property and corrosion resistance in aluminum electrolysis condition.

A large amount of carbon dust is generated in the process of aluminum smelting by molten salt electrolysis. The carbon dust is solid hazardous waste but contains a large quantity of recyclable components such as carbon and fluoride. How to recycle carbon dust more effectively is a challenge in the aluminum electrolysis field. In this study, X-ray diffraction, scanning electron microscope, and other methods were used to analyze the phase composition of electrolytic aluminum carbon dust. The effects of particle size distribution of carbon dust, impeller speed, reagent addition, mixing time, and flotation time on the flotation recovery of carbon dust were studied. The optimal flotation conditions were obtained and the flotation products were analyzed. The results show that the optimal particle size distribution is 70% of particles below 200 mesh, corresponding to a grinding time of 11 min. The optimum speed of the flotation machine was to be between 1600 and 1800 r/min with the best slurry concentration of 20&ndash, 30% and 5 min mixing time, and the collector kerosene was suitable for adding in batches. Under the above conditions, the recovered carbon powder with a carbon content of 75.6% was obtained, and the carbon recovery rate was 86.9%.

This chapter briefly reviews the development of aluminum electrolysis, as well as the electrolysis cells and carbon anodes in the aluminum industry. In addition, the shortcomings of electrolytic cells and carbon anodes used in the aluminum industry are introduced. Reading this part enables readers to understand the development of aluminum electrolysis and to read the rest of the book smoothly.

This chapter briefly introduces the production process of aluminum electrolysis, the conventional production technical conditions, the conventional operation of aluminum electrolysis, flue gas purification, and the economic analysis of primary aluminum production in aluminum plants. After reading this chapter, readers can better understand the economic and environmental benefits of using inert anodes.

Modern aluminum electrolysis in cryolite-alumina melts is energy-intensive, inefficient and environmentally hazardous production. Addressing these significant shortcomings, the technology of low-temperature electrolyte is directed. The basis of low-temperature electrolysis is potassium cryolite, which results in high magnitude and rate of dissolution of alumina. Additive of sodium and lithium fluorides provide the necessary conductivity. Experimental investigation of these properties is extremely time consuming. In this work, as a parameter, which will allow to characterize effectively and rapidly the complexing ability of cryolite melts, the ratio of cationic ion power of Al3+ to the total power of the other cations of the melt is proposed. Regression analyses of the known experimental data establish the existence with a high level of reliability (R2=0.966-0.995) of a directly proportional dependence of this parameter on solubility of alumina and electrical conductivity of cryolite melts.

Optimum condition in caustic leaching test of spent cathode carbon (SCC) from aluminum electrolysis was investigated. The primary and secondary relationship of experimental factors was determined by Taguchi method, under traditional mechanical agitation and ultrasonic, respectively. Initial alkali concentration had significant influence both in ultrasonic-assisted and mechanical agitation leaching processes, and the effect was second only to that of ultrasonic power. Optimal parameters were temperature of 60 °C, leaching time of 50 min, liquid–solid ratio of 10 mL/g, initial alkali concentration of 1 mol/L, particle size of −100 mesh, and ultrasonic power of 400 W. Purity of carbon powder obtained from treatment of spent cathode carbon at optimum conditions was 94.39%. Wastewater was reused after treated. It can be concluded that SCC purification conditions were optimized by synergistic effect of orthogonal and single-factor trails. Ultrasonic plays a notable effect in SCC caustic leaching process.

The problem in the large-scale industrialization for aluminum electrolysis is the corrosion resistance of cermet inert anodes in high temperature molten salts. In this paper, the ion structure of NiFe2O4-10NiO-based cermet anode composition in the electrolyte was investigated. The experiment results show that Al-F and Al-O-F complex ion structures are produced at room temperature and perhaps Me-F (Me=Ni, Cu, Fe), Me-O-F or Me-Al-O-F are also formed. Moreover, Al-F and Al-O-F ion structures exist from room temperature to 700 °C and from 1050 °C to 1200 °C; In the rearrangement and melting process of molten salt at 800 °C -1000 °C, the ionic structures are mainly Al-O-F ions; Me-F and Me-O-F ion structures were not found at high temperature, this indicates that Al in Al-O-F complex ion structures is partially replaced by Fe, Ni or Cu to form MexAlaOyFz(z+2y-2x-3a)-.

In carbon anode baking furnaces, temperature and quality of carbon anodes are significantly affected by the deformation of the flue-walls, where the flue-gases flow and combustion occur. Flue-walls aging gives rise to non-homogeneous baking of the carbon anodes and results in deterioration of the anode quality, which eventually causes instabilities in aluminum reduction cells and overconsumption of anodes and energy. It is imperative to develop a fully coupled 3D multi-physics computational model which takes into account a large number of physical phenomena that play vital roles in the baking process and are affected by the flue-wall deformation mode. In the present study, the effects of flue-wall deformation modes on flue-wall cavity gas flow and anode temperature distribution are investigated. The pressure and flow distributions for different levels of flue-wall deformation are demonstrated. It is perceived that a 100 mm convex mode of flue-wall deformation leads to under-baking of anodes by almost 20 degC. For the concave mode of deformation, since the packing coke thickness reduces, overbaking of anode occurs. The methodology and results presented in the present research can be employed effectively by the aluminum industry in modifying the furnace geometrical and operational parameters to enhance baking uniformity after flue-wall is deformed.

İnsanoğlu,varlığının başlangıcından itibaren doğa ile iç içe olmuş ve doğayı taklitederek çeşitli aletler icat etmiştir. Bu icatların gelişiminde ise en etkilifaktör malzeme bilimi olmuştur. Son yıllarda gelişen teknolojilerle malzemebiliminin önemi artmış ve yeni malzemelerin bulunması zorunlu hale gelmiştir.Seramik malzemeler de insanoğlu için her zaman büyük öneme sahip olmuştur. İleriteknoloji seramikleri uzun ömürlü kullanımı, yüksek performansı, üstünözellikleri ve uygun maliyeti sayesinde birçok ticari uygulamada kullanılmaktadırlar.Titanyum diborür (TiB2), yüksek sertlik, yüksek ergime noktası,mükemmel aşınma ve korozyon direnci gibi özellikleri ile ileri teknolojiseramikleri arasında oldukça önemli bir yere sahiptir.Aşınmaya dayanıklı parçaların üretimi, alüminyum elektrolizi, koruyucu filmtabakaları, askeri uygulamalar (zırh vb.) gibi çok çeşitli uygulama alanlarıbulunmaktadır. Bu makalede, ileri teknoloji seramikler arasında oldukça önemlibir yere sahip olan titanyum diborürün (TiB2) fiziksel ve kimyasalözellikleri, üretim yöntemleri, kullanım alanları ve son yıllarda yapılmışçalışmalar kısaca sunulmaktadır., Humanity has been communed withnature since the beginning of its existence and has invented variousinstruments by imitating the nature. The most effective factor in thedevelopment of these inventions was material science. The importance of thematerial science has increased with the developing technologies in recentyears, and it has become mandatory to find new materials. Ceramic materialshave always been of great importance for human. Advanced technology ceramicsare used in many commercial applications due to their long life, highperformance, superior properties and cost-effectiveness. Titanium diboride (TiB2)with its hardness, high melting point, excellent abrasion and corrosionresistance has a very important place among advanced technology ceramics. Thereare a wide range of applications such as the production of wear-resistantparts, aluminum electrolysis, protective film layers, military applications(armor), etc. In this article, the physical and chemical properties, productionmethods, usage areas and the studies carried out in recent years of titaniumdiboride (TiB2), which has a very important place among the advancedtechnology ceramics, are briefly presented.

The article discusses the issues of constructing a digital model of aluminum electrolysis modes. This model allows to achieve the specified criteria of the production process on the basis of scientific processing of historical data accumulated during the industrial production of aluminum at factories using a mathematical apparatus as well as to obtain recommendations on the values of control parameters. The study is aimed at achieving the business goals of the company’s management in particular on increasing of the profits by improving the quality and quantity of products with reduced production costs.

Cu-Ni-NiFe2O4-NiO cermets doped with Al (0, 0.8, 2, 3.2 wt% ) were prepared by a powder metallurgy process. The effect of Al content, Al adding method and sintering temperature on the microstructure of the cermets were studied using XRD, SEM/EDS, and DSC. The results show that NiO and NiFe2O4 phase are partly reduced to Ni by adding Al at the sintering temperature. The Al element is mainly distributed in the NiFe2O4 phase, and the doping of Al is not conducive to the densification of cermet. The density of the cermet decreases with increasing Al content. The morphology of the metallic phase is related to the Al adding method. Specimens prepared by pre-alloying of Al show smaller metallic particle size than that by mixing of Al. However, the Al adding methods have little effect on the densification and the phase composition. The sintering temperature around the solid phase line of the metallic phase is beneficial to the densification.

The analysis of the current state of world and domestic production of calcined anodes for aluminum electrolysis cells is carried out. The dominant trends are identified, the basic technology is described, and directions for its improvement are indicated.

The analysis of modern technical solutions for the protection of the cathodes of electrolysis cell was carried out. The technological variant of obtaining protective coatings based on nanocrystalline titanium diboride is substantiated and proposed. A comparison of the basic and expected indicators of aluminum production is made using cathodes with protective coatings. A technical solution has been developed to organize the production of nanocrystalline titanium diboride. Its main technical and economic indicators are substantiated.

Today, aluminium dross is normally recycled by melting in a gas fired rotary furnace. Salt is partly used for protection against oxidation of aluminium metal and partly to enhance agglomeration of molten aluminium drops by breaking the oxide layers between them. The separated aluminium metal is then either retuned to the supplier of the dross, or sold to another costumer. The oxide on the other hand, which is mixed with salt and has to be further processed before it is sold as a low grade oxide. This paper describes how aluminum metal and oxide is separated in a plasma heated rotary furnace without the use of salt. The clue is that the plasma gas is a mixture of Ar + H2 and hence giving a reducing conditions. The oxides separated from the dross have been characterized with respect to chemical purity and physical properties, and compared to required properties for use in electrolysis.

A model for predicting anode cover behavior inside aluminum electrolysis cells is presented. The model predicts the transformation of anode cover material into a solid crust, the melting/solidification of the bath and crust, and the heat fluxes escaping the anode cover. The model is validated with experimental data taken on industrial electrolysis cells. The temperature and positions of the top crust, the heat flux escaping the anode cover, and the height of the cavity are presented, along with the model predictions. The effect of bath temperature on the crust formation is further investigated. Results show that the bath temperature can greatly enhance the rate of crust formation.

Many factors may contribute to loss of current efficiency (CE) in aluminum reduction and one of them is a presence of impurities. In this work, the effect of phosphorus on CE is studied in a laboratory cell at different current densities. Due to a growing trend toward higher amperage in retrofitted industrial cells, a study is performed both at a representative industrial current density (0.8 A/cm(2)) and at a high current density (1.5 A/cm(2)). More resolution was obtained at phosphorus levels comparable to typical industrial concentration in aluminum reduction cell (0-220 mg/kg). It is shown that the effect of phosphorus on the CE is more significant at high current density. Trend lines for the whole concentration range btw. 0 and 630 mg/kg showed a decrease of 1.1% in CE per 100 mg/kg for the high current density and 0.67% per 100 mg/kg at the low current density. The detrimental effect was more pronounced for relatively low phosphorus contents up to 220 mg/kg. A trend line for that smaller range revealed a reduction of 2.5% per 100 mg/kg of phosphorus at 1.5 A/cm(2), while at 0.8 A/cm(2) a reduction of 0.92% per 100 mg/kg of phosphorus was obtained. This indicates that increasing amperage in retrofitted cells may amplify the detrimental effect of impurities on the current efficiency., Funding for this work was provided by Alcoa Fjardaal and HRV Engineering. Assistance from Manolescu and Sintef staff is gratefully acknowledged., "Peer Reviewed"

The new aluminum electrolysis technology based on inert electrodes has received much interest for several decades because of the environment and energy advantages. The key to realize this technique is the inert anode. This article presents China’s recent developments of NiFe2O4-based cermet inert anodes, which include the optimization of material performance, the joint between the cermet inert anode and metallic bar, as well as the results of 20 kA pilot testing for a large-size inert anode group. The problems NiFe2O4-based cermet inert anodes face are also discussed.

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.

Experiments were conducted using industrial anodes to determine the influence of baking temperature and operating current density upon carbon sloughing.

Three aluminum electrolysis cells with a novel uneven cathode bottom are being operated successfully in Chongqing Tiantai Aluminum Industry Co., Ltd., China. More and more aluminum smelters are using this type of cathode. In the past year the three 168 kA cells have produced steadily at low cell voltages of 3.70 V to 3.75 V, and the current efficiency (CE) has been improved by at least 1 % in comparison with 127 traditional model cathode cells in the same potline. The technical characteristics of the cells are described in this paper.

The ramming paste behavior is a key parameter in the cell performance used for the aluminum electrolysis. This anthracite and coal tar pitch mixture bakes during the cell start-up and chemical transformations in the ramming paste are observed. The mechanical properties of the paste are related to these transformations and change with time and temperature during the cell start-up. This paper presents the methodology used to determine the evolution of the mechanical properties of ramming paste, using experimental conditions representative of a cell startup. Experimental results for temperatures from ambient to 960°C are presented and the effects of the test conditions are discussed.

Al-RE Alloys have attracted much attention in recent years due to their great potential in many advanced applications. In this work, Al-Sc-Zr alloys were prepared in a laboratory electrolysis cell. Effects of Sc2O3 and ZrO2 additions and the electrolysis time on Sc-Zr contents and their ratio in the alloys were investigated in Na3AlF6 based melt at 960 °C. SEM and ICP-AES show that Sc and Zr contents in the alloy produced were 0.25–0.32 wt% and 0.26–1.24 wt%. SEM-EDS analysis reveals that Al3(Sc,Zr) particles form in Al alloy prepared by electrolysis. Cyclic voltammetry results demonstrate that Zr4+ proceeds a two-step process electrolysis at -0.7V and -1.05V, respectively, while no single peak appears for Sc deposition.

Cold spray deposition was evaluated for the production of inert anodes for Al electrolysis from mechanically alloyed Cu−Ni−Fe powders. Cu65Ni20Fe15 (in wt. %) alloy was first prepared from elemental Cu, Ni, Fe powders using an attritor. After 40 h of milling, a nanocrystalline and monophasic Cu(Ni,Fe) solid solution was formed. It was shown that the particle size of the milled powder can be controlled with the addition of stearic acid to the initial powder mixture. In a second step, the cold spray parameters (pressure and temperature of the carrier N2 gas) were optimized in order to maximize the impact velocity of the Cu65Ni20Fe15 particles on the substrate. Then, thick (1100 μm), dense (porosity of 1− 2 %) and adherent (adhesion strength of 15 MPa) coatings of Cu65Ni20Fe15 on C63000 substrate (copper aluminium bronze alloy) were produced. No structural change of the Cu65Ni20Fe15 alloy was observed during cold spray processing., 2013 TMS Annual Meeting and Exhibition, 3-7 March 2013, San Antonio, TX, USA, Series: TMS Light Metals

Spark plasma sintering was used to prepare Fe-Ni (Cu-41.32wt.% Cr) alloy in order to enhance the properties as inert anode for aluminum electrolysis. The effect of different sintering processes on the microstructures and properties of Fe-Ni alloy were studied by OM, SEM and EDS. The results show that the sintering process of milled powders can be divided into three stages: particles bonding, sintering neck growing, closed pole gap becoming spherical and narrowing. The SPS process of milled powders has some advantages of reacting at lower temperatures, completing faster and being densified easier than ordinary sintering. The density of Fe-Ni sample is improved and porosity is decreased as the sintering temperature is increased and holding time is extended. 1273K and 5min are the best parameters.

Determination of dissolution rate of alumina is one of the classical problems in aluminum electrolysis. A novel method which can measure the dissolution rate of alumina was presented. Effect of factors on dissolution rate of alumina was studied intuitively and roundly using transparent quartz electrobath and image analysis techniques. Images about dissolution process of alumina were taken at an interval of fixed time from transparent quartz electrobath of double rooms. Gabor wavelet transforms were used for extracting and describing the texture features of each image. After subsampling several times, the dissolution rate of alumina was computed using these texture features in local neighborhood of samples. Regression equation of the dissolution rate of alumina was obtained using these dissolution rates. Experiments show that the regression equation of the dissolution rate of alumina is y=−0.000 5x3+0.024 0x2−0.287 3x+ 1.276 7 for Na3AlF6-AlF3-Al2O3-CaF2-LiF-MgF2 system at 920 °C.

Laboratory-scale carbon anodes were produced by a new method of high-temperature mould pressing, and their physico-chemical properties were studied in laboratory. The results showed that the bulk density of carbon anodes produced by high-temperature mould pressing are 1.61-1.63g/cm3, they are higher than industrial carbon anode by 0.06 g/cm3, but the specific electrical resistance is higher and crushing strength is lower.

An apparatus to measure compressive creep in carbon cathode materials has been developed. Short-time creep were measured at 30°C，965°C and during aluminum electrolysis at 965°C. The creep strain increases with stress, indicating that the creep behavior is of the stress dependency. The ranking from low to high creep was at 30°C

Experimental investigation of sodium expansion in TiB2-carbon with different TiB2 content during aluminum electrolysis was carried out in a laboratory cell. The model based on the swelling due to the sodium penetration has been discussed, and relationship between the sodium expansion and time has been proposed that has been calculated by MATLAB. The proposed model was extended to the three-dimensional distribution of sodium concentration, stress and first principal stress that was implemented by ANSYS. Validation of this numerical tool was achieved through the Rapoport tests. The results show good agreement between analytical solution and numerical modeling as well as between experimental and numerical results. This means that the chosen numerical model is suitable to predict sodium expansion as well as induced stresses in TiB2-carbon cathodes and is great interest in the work to extend aluminum reduction cell lifetime.

The reaction between Si3N4 and AlF3 had been investigated in CO atmosphere at high temperature. Experimental results are shown that the reaction between Si3N4 and AlF3 is accelerated with the rise of temperature. At the temperature of 950 (aluminum electrolytic operation temperature is 935±15), there is obvious reaction between Si3N4 and AlF3; under this experiment condition, Si3N4 converted into Si2N2O partly, Si2N2O can also react with AlF3. The reaction products of Si3N4 with AlF3 are SiF4 (g) and AlN, while the reaction products of Si2N2O with AlF3 are SiF4 (g) and Al8O3N6. So, during the usage of Si3N4-bonded SiC sidewall brick in aluminum electrolysis cells, the content of Si3N4 in Si3N4-SiC block are reduced which can bring down the corrosion of aluminum electrolyte to the sidewall materials.

The sources of PAH emission from the Soderberg anode surface of aluminum electrolysis cells are analyzed and measures for their minimization due to evaporative cooling of the anode to temperature 100 °C are offered.

One of the main causes of the failure of electrolysis cells is the destruction of barrier (refractory) materials. This work is aimed at the establishment of the main regularities of the interaction between fluorides and various barrier materials. A thermodynamic analysis of the processes running in refractory materials of the cathode assembly of electrolysis cells, as well as the results of an X-ray phase analysis of the fragments of the refractory materials, allowed one to reveal the major mechanism of their destruction, which consists of the occurrence of gas-phase reactions. On the basis thereof, recommendations were developed aimed at increasing the lifetime of the barrier materials of electrolysis cells for aluminum production.

The Acknowledgment at the end of the paper should read: Financial support from the National Natural Science Foundation of China (NSFC) (No. 170410656) and the Collaborative Innovation Center of Nonferrous Metals, Henan Province (15A450001) is gratefully acknowledged.

Recent developments in the preparation, sintering process, mechanical properties, and thermal shock resistance of cermet inert anodes for aluminum electrolysis are reviewed in this paper. To obtain the desired technologies of low-temperature activated sintering of cermet inert anodes, the effects of material composition, sintering atmosphere, sintering temperature, and sintering aids on the densifi cation and microstructure of NiFe2O4-10NiO- based ceramics and cermets were studied. To obtain the toughening and strengthening technology of the cermet, the effects of material composition including ceramic and metallic phases are discussed. The cermet inert anodes with high density and mechanical properties were prepared through adjustment of material composition and sintering technology and selection of feasible sintering aids.

The effects of BaO addition on the phase composition, relative density and electric conductivity of x Cu/10NiO-NiFe 2 O 4 ( x =5, 10) cermets were studied, which were prepared with cold isostatic pressing-sintering process. The results show that the relative densities of 5Cu/10NiO-NiFe 2 O 4 cermet doped with 1% BaO (mass fraction) and 10Cu/10NiO-NiFe 2 O 4 cermet doped with 1% BaO sintered at 1 473 K in nitrogen atmosphere, are increased by about 9.86% and 9.75% compared with the undoped BaO cermets, respectively. And the electric conductivities 22.79 S/cm of 5Cu/10NiO-NiFe 2 O 4 cermets adding 1% BaO and 23.10 S/cm of 10Cu/10NiO-NiFe 2 O 4 cermets adding 1% BaO are obtained, which are 2.21 times and 1.47 times of those of undoped samples, respectively. Moreover, the 10Cu/10NiO-NiFe 2 O 4 cermets doped with 1% BaO have a maximum σ 0 of 58.91 S/cm and electric conductivity of 23.10 S/cm at 1 233 K. Maybe low melting-point phases of BaFe 2 O 4 and Ba 2 Fe 2 O 5 have an excellent electric conductivity in x Cu/10NiO-NiFe 2 O 4 ( x =5, 10) cermets at 1 233 K.

The phase diagram of the system Na3AlF6–NaVO3 was determined by means of thermal analysis. The system is a simple binary eutectic one. The eutectic point was estimated at x(NaVO3) = 0.975 and teut = 617°C. The XRD patterns of samples after thermal analysis revealed the presence of cryolite and NaVO3 only supporting the above assumption of a simple eutectic binary system.

Laboratory scale transparent aluminum electrolysis cells were used to study anodic bubble behavior, including bubble layer thickness, bubble shape and coverage at the anode bottom surface, and the resultant cell voltage drop in a very similar environment to real industrial cells. The observation was conducted using two transparent cells, one with side-view and the other with a bottom-view cell design. For the side-observation experiment, the evolution of bubble layer thickness and bubble rising process were studied. In the bottom-observation experiment, bubble behavior was investigated on both unslotted and slotted anodes. Cell voltage was simultaneously recorded for a quantitative investigation of its relevance to bubble coverage. It was found that the cell voltage drop is very consistent with bubble coverage, with a high voltage drop corresponding to a high bubble coverage. The coverage of anodic gas bubbles decreases with the increase of current density. These phenomena were observed on unslotted and slotted anodes. The comparison of unslotted anode and slotted anode indicated that the slot significantly reduces the cell voltage drop, voltage drop fluctuations and bubble coverage.

UC RUSAL remains one of the world’s leaders in primary aluminium producing eight percent of total world output in 2013. In 2012, following the global industrial trends, Management initiated several technical projects with the goal to decrease power consumption in all reduction technologies used. Below are the major measures: 1. Energy balance adjustment to reduce heat generation by a stage-by-stage decrease in the anode-cathode distance (ACD) down to the Limit values, resulting in the specific power consumption has decreased by 300 DCkWh/t. 2. The introduction of slotted anodes for the PB cells at the Krasnoyarsk and Irkutsk smelters decreasing specific power consumption by an average of 200 DCkWh/t. 3. Advanced energy-saving cathode designs are currently tested with a potential for decreasing 300 DCkWh/t or more.

Grey relational analysis was a data processing method used to sort out the correlation extent of effect factors in a system with uncertain information. In the paper, it was applied to evaluate the effect of operating parameters on corrosion rates of inert anodes in aluminum electrolysis. The corrosion rates of 5%Ni-NiFe2O4 cermet anodes were investigated as a function of some operating parameters. To reach a better understanding of the corrosion mechanism, the behavior of the anodes was observed under some designated conditions, such as in pure cryolite solvent, high current densities, and varying cathode surface areas. It was confirmed that low alumina concentration and high temperature were detrimental. The experiment results showed that grey relational analysis was an innovative data process method used to rank the corrosion extent of effect factors in the corrosion processes.

Results of testing the side-wall lining made up from nitride-bonded silicon-carbide plates for an aluminum electrolysis cell equipped with pre-fired anodes are reported. Technical and economic characteristics of the performance of electrolysis cells equipped with the newly-designed lining are superior to those of standard electrolysis cells equipped with the carbon-block refractory lining.