Electrometallurgical

P. L. Claessens and G. B. Harris, Electrometallurgical Plant Practice, Pergamon Press, Inc., New York, 1990. 

A. LaVecchia, Electrochim. Met. 3(1), 71 (1968) Symposium on Sulfamic Acid andits Electrometallurgic Applications (Proceedings), Polytechnic School of Milan, Milan, Italy, May 25, 1966. 

Electrochemical processes in melts are often attended by side reactions and phenomena complicating the primary process. This is true, in particular, for the technically very important class of reactions in which a number of metals (calcium, barium, and others) are obtained electrometallurgically from molten salts. In many of these processes the metal that is deposited (sometimes in a highly disperse state) is found to interact with the corrosive melt for example, in a reaction such as... 

The text so far has pertained mostly to energy- and environment-related considerations that are relevant to certain representative pyrometallurgical and electrometallurgical operations. The present section deals more generally with such considerations in the context of hydrometallurgical operations. 

See for example Electrometallurgical Techniques for DOE Spent Fuel Treatment Final Report, National Research Council, National Academy Press, Washington, D.C., 2000 Alternatives for High-Level Waste Salt Processing at the Savannah River Site, National Research Council, National Academy Press, Washington, D.C., 2000. 

Pereira, C., Hash, M. C., Lewis, M. A., Richmann, M. K. Basco, J. 1999. Incorporation of radionuclides from the electrometallurgical treatment of spent fuel into a ceramic waste form. Materials Research Society Symposium Proceedings, 556, 115-120. 

Broadhead, K. G., D. E. Shanks, and H. H. Heady Fast-Neutron Activation Analysis in Molten Salt Electrometallurgical Research. Modern Trends in Activation Analysis-Proceedings of the 1965 International Conference in College Station, Texas, April, 1965. A and M College of Texas, College Station, Texas, pp. 39—43 (1965). 

The same arrangement is applied for electrometallurgical processes where insoluble anodes are used and the liberated gas is allowed to esoape freely into the atmosphere. 

The design of connection of the electrodes to the current conductors depends on the nature of the process. There is a considerable difference between the connections used in electrolyzers where periodical removal of electrodes from the bath is required and the connections used in electrolyzers where the electrodes are not removed and form a fixed part of the equipment. The first case is encountered mainly in electrometallurgical refining processes where anode scraps and cathodes with the deposited metal are removed. In such oases... 

In electrolyzers where during the operation no replacement of the electrolyte is required (e. g. electrometallurgical refining processes) mixing can be carried out by a suitably designed stirrer or by gas (air) which is led in through a perforated pipe which reaches to the bottom of the vessel. 

GWye), development is now centered on (1) reducing plutonium in the waste, (2) the liquid metal benefit to safety, and (3) electrometallurgical reprocessing at each reactor site, thereby reducing proliferation concern. 

Preparation.2—The methods employed in the manufacture of copper from its ores may be classified in three main divisions (1) dry methods, for ores with more than 4 per cent, of copper (2) wet methods, for ores with less than 4 per cent, of copper (3) electrometallurgical methods. 

Several processes for the extraction of copper by electrometallurgical methods have been devised. The Marchese patent2 aimed at the decomposition of copper matte and deposition of the copper simultaneously in a sulphuric-acid electrolyte with a copper-matte anode and a copper cathode. In Siemens and Halske s patent3 the copper of the ore was oxidized to the cupric state by an acid solution of ferric sulphate, and the copper deposited electrolytically in a second vessel with a diaphragm separating the cathode and the anode. Neither process has been commercially successful. 

Figure 3.1. Schematic of electrometallurgical processes used to purify metals. Shown is the (a) Downs cell used to purify sodium metal and (b) Hall cell used to purify aluminum metal. Reproduced with permission from Chemistry The Central Science, 8th ed., Brown, LeMay, Bursten. Copyright 2002 Prentice-Hall.

The liquid products tend to be unsaturated and, because sulfur compounds are relatively more concentrated in heavy portions of crude oil, also tend to be rather high in sulfur content. The octane number of the gasoline depends upon the character of the feed, and typically ranges from 60-65 for paraffinic stocks to as high as 80 for highly naphthenic stocks. The coke can be used as fuel but in many cases is of a high quality suitable for use in the manufacture of carbon electrodes for the aluminum or other electrometallurgical industries. 

The high resistance of titanium diboride, TiB2, to many metal melts, particularly aluminum, has led to its use as an electrode and crucible material for electrometallurgical processes. 

R. Combes, B. Tremillon, F. De Andrade, M. Lopes and H. Ferreira, Definition and Use of an Oxoacidity Function O for the Comparison of Acidity Levels at 1000 K of Some Chloride Melts Involved in Electrometallurgical Processes, Anal. Lett. 15A (1982) 1585-1600. 

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