Download or read book The Oxidation and Protection of Heterogeneous Carbon Anodes Used for Aluminium Smelting written by and published by . This book was released on 1988 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Oxidation and Protection of Heterogeneous Carbon Anodes Used for Aluminium Smelting written by Ann Marie Fitchett and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pre-baked carbon anodes are commonly employed in the production of aluminium by electrolysis (in the Hall-Heroult process). They are consumed in the process, both by the electrochemical reaction, and as "excess" carbon consumption. All carbon consumed in reactions other than those resulting in the deposition of aluminium metal is classified as excess. Aluminium smelter technologists tend to refer to the total carbon consumption relative to the amount of metal produced. Values reported vary between 0.40 and 0.48 kilograms of carbon per kilogram of aluminium, and between 0.06 and 0.14kgC/kgAl is typically considered to be excess. Oxidation by air ("airburn") of the anode surface area protruding above the melt accounts for between 0.03 and 0.05kgC/kgAl, in spite of attempts to protect the anode carbon. A significant proportion may be saved by improved carbon quality, technology, and operating practice: small improvements often implying considerable financial savings in raw materials costs. The overall objective of the investigations undertaken was to quantify the importance of airburn and airburn protection media for various carbon qualities. Apparatus was developed for the measurement of carbon oxidation rates at temperature. Temperature dependence studies of unprotected carbon core specimens from plant anodes showed that below 400oC, the oxidation rates were always extremely low. This temperature probably represents the ignition temperature limit. They then increased rapidly up to approximately 700oC, above which the airburn rates increased only gradually as the temperature was raised. This was probably due to mass transfer effects becoming rate-controlling. At a given temperature, for unprotected carbons, a significant difference was observed in airburn rates for different formulations this difference being up to 60%. Whilst differences were apparent for different pitching levels and formulations, local variations in other properties made it difficult to ascribe accurate trends. This was consistent with work done by other researchers, and is a consequence of the heterogeneous nature of the material. Attempts were made to relate the measured oxidation rates to carbon quality, as quantified using X-ray diffraction and porosimetry techniques. Various forms of anode protection were investigated, including impregnation using a solution of sodium tetraborate ("Borax"), coating with aluminium spray, and coverings of powdered alumina ore and crushed bath. Aluminium spray was shown to reduce the airburn rate by up to 60% in the temperature range considered, while "Borax" was shown to be of limited benefit. A marked reduction in airburn rate was achieved by using alumina or crushed bath at a given temperature. For 15mm coverage the reduction was over fourfold. Above 25 mm alumina or crushed bath cover the rate of decrease became much smaller, but the differences due to carbon quality were also very small. There was little difference in the use of crushed bath as opposed to alumina for airburn protection below 650oC. In the temperature region 650oC to 750oC, it appeared that a decrease in airburn rate occurred when crushed bath protection was used, and this may have been associated with a sintering/blocking effect. Above 750oC shrinkage allowed ingress of air, and the rate again became similar to that of alumina. A plant trial in an aluminium smelter was initiated particularly to evaluate the protection afforded by powdered alumina and aluminium spray, and the performance of anodes of different heights. An important part of the programme was also the collection of data to assist in the refinement of the airburn model being developed. This model allowed a reasonable prediction of the expected carbon consumption by oxidation for specific anode conditions. Based on the assumption that airburn in the pot is a function of temperature and the availability of oxidizing gas, anode temperature and cover data were recorded. These were then related to the depth of carbon consumed at each face during anode life. Average timetemperature profiles obtained showed a rapid increase in top temperature up to about 500oC in about 24 hours. This was followed by a linear rate of increase up to a peak temperature which is dependent on anode height, cover depth and stall location. Carbon ratios obtained for the different anode conditions showed that most of the difference in carbon consumption could be accounted for by airburn. Values for depth of carbon consumed at the anode tops were very similar, varying slightly with the depth of ore cover measured. The main differences were found in the mass of carbon consumed at the anode sides, particularly at the centre channel. Aluminium spray provided significant protection on all sides. However, at the centre channel some of the spray was lost by burning, or in some cases, flux wash. In the light of the results obtained, recommendations for improvements in pot operating practices for better anode performance can be made. These include improvements both in the quality and distribution of anode protection. The minimisation of cell disturbances and exposure of the anodes to flame and bath are also recommended, together with the minimisation of unnecessary heat generation.
Download or read book Essential Readings in Light Metals Electrode Technology for Aluminum Production written by John A. Johnson and published by John Wiley & Sons. This book was released on 2013-04-03 with total page 1222 pages. Available in PDF, EPUB and Kindle. Book excerpt: This compilation is the most comprehensive historical collection of papers written on primary aluminum science and technology. It is a definitive reference in the field of aluminum production and related light metals technologies and contains a strong mix of materials science and practical, applied technology. Written for materials scientists and engineers, metallurgists, mechanical engineers, aerospace and automobile engineers, electrical and electronics engineers, this volume is a valuable resource for the global aluminum and light metals industries.
Download or read book Essential Readings in Light Metals Volume 4 Electrode Technology for Aluminum Production written by Alan Tomsett and published by Springer. This book was released on 2016-12-27 with total page 1212 pages. Available in PDF, EPUB and Kindle. Book excerpt: This compilation is the most comprehensive historical collection of papers written on primary aluminum science and technology. It is a definitive reference in the field of aluminum production and related light metals technologies and contains a strong mix of materials science and practical, applied technology. Written for materials scientists and engineers, metallurgists, mechanical engineers, aerospace and automobile engineers, electrical and electronics engineers, this volume is a valuable resource for the global aluminum and light metals industries.
Download or read book Influence of Raw Material Properties on the Reactivity of Carbon Anodes Used in the Electrolytic Production of Aluminium written by Sheralyn Marie Hume and published by . This book was released on 1993 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Oxidation Reactions of Heterogeneous Carbon Cathodes Used in the Electrolytic Production of Aluminium written by Bryony Joanne James and published by . This book was released on 1997 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book World Aluminum Abstracts written by and published by . This book was released on 1970 with total page 986 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Who s who in Technology written by and published by . This book was released on 1986 with total page 822 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Corrosion Science and Technology written by David E.J. Talbot and published by CRC Press. This book was released on 2018-01-29 with total page 699 pages. Available in PDF, EPUB and Kindle. Book excerpt: Twenty years after its first publication, Corrosion Science and Technology continues to be a relevant practical guide for students and professionals interested in material science. This Third Edition thoroughly covers the basic principles of corrosion science in the same reader-friendly manner that made the previous edition invaluable, and enlarges the scope of the content with expanded chapters on processes for various metals and new technologies for limiting costs and metal degradation in a variety of commercial enterprises not explored in previous editions. This book also presents expertly developed methods of corrosion testing and prediction.
Download or read book Molten Salt Technology written by David G. Lovering and published by Springer. This book was released on 2014-11-14 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Copper and Bronze in Art written by David A. Scott and published by Getty Publications. This book was released on 2002 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a review of 190 years of literature on copper and its alloys. It integrates information on pigments, corrosion and minerals, and discusses environmental conditions, conservation methods, ancient and historical technologies.
Download or read book Extractive Metallurgy of Niobium written by A.K. Suri and published by Routledge. This book was released on 2017-11-13 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: The growth and development witnessed today in modern science, engineering, and technology owes a heavy debt to the rare, refractory, and reactive metals group, of which niobium is a member. Extractive Metallurgy of Niobium presents a vivid account of the metal through its comprehensive discussions of properties and applications, resources and resource processing, chemical processing and compound preparation, metal extraction, and refining and consolidation. Typical flow sheets adopted in some leading niobium-producing countries for the beneficiation of various niobium sources are presented, and various chemical processes for producing pure forms of niobium intermediates such as chloride, fluoride, and oxide are discussed. The book also explains how to liberate the metal from its intermediates and describes the physico-chemical principles involved. It is an excellent reference for chemical metallurgists, hydrometallurgists, extraction and process metallurgists, and minerals processors. It is also valuable to a wide variety of scientists, engineers, technologists, and students interested in the topic.
Download or read book Handbook of Cathodic Corrosion Protection written by Walter von Baeckmann and published by Elsevier. This book was released on 1997-10-17 with total page 601 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive handbook covers all aspects of cathodic protection in terms of both practice and theory.
Download or read book Aluminium Smelter Technology written by Kai Grjotheim and published by . This book was released on 1988 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aluminium Electrolysis written by Kai Grjotheim and published by . This book was released on 1982 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book CIM Bulletin written by Canadian Institute of Mining and Metallurgy and published by . This book was released on 1997 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Light Metals 2017 written by Arne P. Ratvik and published by Springer. This book was released on 2017-02-10 with total page 1385 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Light Metals symposia at the TMS Annual Meeting & Exhibition present the most recent developments, discoveries, and practices in primary aluminum science and technology. The annual Light Metals volume has become the definitive reference in the field of aluminum production and related light metal technologies. The 2017 collection includes papers from the following symposia:Alumina and BauxiteAluminum Alloys, Processing, and CharacterizationAluminum Reduction TechnologyCast Shop TechnologyCast Shop Technology: Recycling and Sustainability Joint SessionElectrode TechnologyThe Science of Melt Refining: An LMD Symposium in Honor of Christian Simensen and Thorvald Abel Engh
