Aluminum reduction cell

The principal use of AIF. is as a makeup ingredient in the molten cryoflte, Na.. AIF AI2O2, bath used in aluminum reduction cells in the HaH-Haroult process and in the electrolytic process for refining of aluminum metal in the Hoopes cell. A typical composition of the molten salt bath is 80—85%... 

Emissions for Three Electrolytic Aluminum Reduction Cell Types Using Best Available... 

Soderberg aluminum reduction cells for simultaneous removal of aluminum oxides, solid and gaseous fluoride, tar mist (condensible hydrocarbons), and SO2,... 

E. Bakke, On the Application of Wet Electrostatic Precipitators for Control of Emissions from Soderberg Aluminum Reduction Cells, A.I.M.E. Meeting, Dallas, Texas, February 1974. 

Materials made of silicon nitride, silicon oxynitride, or sialon-bonded silicon carbide have high thermal shock and corrosion resistance and may be used for pump parts, acid spray nozzles, and in aluminum reduction cells (156—159). A very porous silicon carbide foam has been considered for surface combustion burner plates and filter media. It can also be used as a substrate carrying materials such as boron nitride as planar diffusion source for... 

E. Demedde, E. L. Cambridge, Gas induced circulation in an aluminum reduction cell, Paper presented at the AIME Annual Meeting, New York, 1975. 

REDUCED CURRENT DENSITY IN HALL PROCESS ALUMINUM REDUCTION CELLS 2160 kWh per Ton of Primary Aluminum 350 per Annual Ton of Primary Aluminum 48 x 109 per Quad of electricity 1-1/4 Times Conservation... 

Soderberg anodes, use of which is declining, are baked directly in the aluminum reduction cell. In this case, petroleum coke is mixed with 25 to 30% binder the mixture is carbonized by the heat of the electrolysis bath (940 to 980 °C). 

Tessier, J., Duchesne, C., et al. (2011). "Multiblock monitoring of aluminum reduction cells performance." Light Metals 2011 407-412. 

Fleer, M., Lorentsen, O.-A., Harvey, W. et al. (2010) Heat recovery from the exhaust gas of aluminum reduction cells, in Light Metals, TMS, pp. 243-248. 

On the other hand, electrical resistance of cathode materials is an importance performance concerned to energy consumption in aluminum reduction cells. It has been found that the electrical resistance for carbon cathodes are influenced by materials, microstructures and... 

Bijun Ren et al., Application of TiB2 Coating Cathode Blocks Made by Vibration Molding for 300 kA Aluminum Reduction Cells, Light Metals, (2007), 1047-1050. 

Aluminum. All primary aluminum as of 1995 is produced by molten salt electrolysis, which requires a feed of high purity alumina to the reduction cell. The Bayer process is a chemical purification of the bauxite ore by selective leaching of aluminum according to equation 35. Other oxide constituents of the ore, namely siUca, iron oxide, and titanium oxide remain in the residue, known as red mud. No solution purification is required and pure aluminum hydroxide is obtained by precipitation after reversing reaction 35 through a change in temperature or hydroxide concentration the precipitate is calcined to yield pure alumina. 

No cryolite is actually needed once the smelting process is in operation because cryolite is produced in the reduction cells by neutralizing the Na20 brought into the cell as an impurity in the alumina using aluminum fluoride. 

Aluminum obtained by electrolysis of cryoHte baths contains iron [7439-89-6] and siUcon [7440-21-3] as impurities. Iron content may vary from 0.05 to 0.4% and siUcon from 0.05 to 0.15% depending on the raw materials and the age and condition of the reduction cell. Primary aluminum metal also contains small, usually not to exceed 0.05% in total, amounts of many other elements. Some of these trace impurities are Cu, Mn, Ni, Zn, V, Na, Ti, Mg, and Ga, most of which are present in quantities substantially below 100 ppm. 

Sources/Uses. Occur as emissions from coke ovens, from coking of coal tar pitch, and ftom Soderberg aluminum reduction electrolytic cells used for base coatings and paints for roofing and paving and as a binder for carbon electrodes... 

Fig. 1. Aluminum electrolytic reduction cell of the pre-bake type. The anodes are constructed of separate blocks of carbon which have been pre-haked. There is a lead to the main bus bar from each block. (Reynolds Metals Company)...

The use of electrodes in aluminum reduction operations is associated with the generation of several types of wastes (Dinman 1983 IARC 1984). In aluminum reduction facilities using the prebake process, PAHs are generated. In aluminum reduction operations using the Soderberg cell process, considerable amounts of volatiles from coal tar pitch, petroleum coke, and pitch, including PAHs, are generated. 

While the aluminum reduction process is primarily electrolytic, much of the power required is consumed through cell resistance, which keeps the electrolyte in a fluid state. 

You decide to construct a zinc/aluminum galvanic cell in which the electrodes are connected by a wire and the solutions are connected with a salt bridge. One electrode consists of an aluminum bar in a 1.0 M solution of aluminum(ni) nitrate. The other electrode consists of a zinc bar in a 1.0 M solution of zinc(II) nitrate. Zinc(II) has a more positive standard reduction potential than A1(III). 

---