Abstract
This chapter covers the changes in calcination technology, energy consumption, air pollution control and quality of SGA developed over time since the end of the 2nd World War and up until today. The demand for SGA with high specific surface area ranging from 50 to 80 m2/g (BET method) originated from the alumina smelter customers driven by the increasing need to capture HF gas emitted from the smelter cell’s by so-called Dry-Scrubbing with virgin alumina in Gas Treatment Centers (GTC) located at the alumina smelter. The physio-chemisorbed HF on the virgin alumina collected in the GTC as secondary alumina, was then fed to the alumina smelter cells, or pots, via pot feeding systems. This development starting around 1970 made the Floury type SGA, with very low specific surface area around 5 m2/g, obsolete, and Floury SGA was gradually replaced with so-called Sandy type SGA. The oil crisis around 1972 accelerated the development, scale-up and commercialization of stationary calciners for production of SGA initiated by Alcoa in the mid 1950 ties. The 25–30% reduction in specific thermal energy consumption in Rotary Kilns, when compared to Stationary Calciners was a very strong driver. The retention time in the Rotary Kiln was reduced from hours to minutes in Fluidized Bed calciners and from minutes to seconds in Gas Suspension or Flash calciners. Simultaneously with the above development several Rotary Kilns were retrofitted with pre-heater cyclones, and in one case also with a calciner furnaces, to reduce the specific thermal energy consumption and increase the production capacity of SGA. The largest Rotary Kilns for production of SGA had a design capacity of 1400 tpd SGA. This capacity was exceeded several times at Queensland Alumina, Australia, where the new Gas Suspension Calciners installed in 2002–2004 was designed for 4500 tpd SGA, driven by economy of scale. Today, the preferred design capacity of stationary calciners is around 3500 tpd SGA to match the single train production capacity of the Bayer Process circuit in modern alumina refineries. However, the above technology shifts have not come without new challenges to the Bayer process design. One such major challenge is to produce a hydrate quality, which upon calcination to SGA in stationary calciners, results in a particle size distribution and strength as SGA, that meets the specification of the smelters. Driven by environmental requirements of reduced dust emission Queensland Alumina, Australia, as the first in the alumina industry, decided in 2002, to install Baghouses or Fabric filters on their new Gas Suspension Calciners instead of Electrostatic Precipitators (ESPs), in order to avoid excessive dust emission during a power failure. Up until today heavy fuel oil, natural gas and coal gas (CO + H2) is used as fuel in stationary calciners. But the challenges laying ahead with a predicted increase of the global warming of mother earth, makes hydrogen produced by electrolysis powered with renewable energy the preferred fuel for the not so distant future with potential to make the production of SGA CO2 free.
Benny E. Raahauge is deceased.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Similar content being viewed by others
References
O. Tschamper,Improvements by the new Alusuisse process for producing coarse aluminium hydrate in the bayer process, in Light Metals, pp. 103–115 (1981)
W.C. Sleppy, et al., Non-metallurgical use of alumina and bauxite, in Light Metals, pp. 117–124 (1991)
B. Welch, Chapter 9.12b “aluminum”, in SME mineral processing and extractive metallurgy handbook (2019)
T. Ashida, et al., New approaches to phase analysis of smelter grade alumina, in Light Metals, pp. 93–96 (2004)
S.J. Lindsay, Customer impacts of Na2O and CaO in smelter grade alumina, in Light Metals, pp. 163–167 (2012)
M. Ishihare,et al., Conversion of conventional rotary kiln into effective sandy alumina calciner, in Light Metals, pp. 143–152 (1983)
G. Labriot, Modification of rotary kiln for calcination of alumina and metal hydrates, in Light Metals, pp. 153–158 (1983)
B.E. Raahauge, et al., Experience with gas suspension calciner for alumina, in Light Metals (1991)
W.M. Fish, Alumina calcination in the fluid-flash calciner, in Light Metals, pp. 673–682 (1974)
L. Reh, H. W. Schmidt, Application of circulating fluid bed calciners in large scale aluminaplants, in Light Metals, pp. 519–532 (1973)
B.E. Raahauge, FLS stationary calciner for alumina—a new simple approach in alumina calcining, in ICSOBA 1979, Calgari, Sardegna, Italy (1979)
T.A. Venugopalan, Experience with gas suspension calciner alumina, in Alumina Quality Workshop, pp. 53–66 (1988)
L. Reh, New and efficient high-temperature processes with circulating fluidized bed reactors. Chem. Eng. Technol. 18, 75–89 (1995)
S. Hundebøl, S. Kumar, Retention time of particles in calciners of the cement industry. Zement-Kalk-Gips, Nr. 8, 422–425 (1987)
L.M. Perander, et al., Two perspectives on the evolution and future of alumina, in Light Metals, pp. 151–155 (2011)
B.E. Raahauge, N. Devarajan, Experience with particle breakdown in gas suspension calciners, in ICSOBA, Dubai, UAE (2015)
Aughinish Alumina—Up-grade project 2001 introducing FLS Cyclone technology
C. Klett, Alumina calcination: a mature technology under review fromsupplier perspective, in Light Metals, pp. 79–84 (2015)
M. Missalla, et al., Significant improvement of energy efficiency in alunorte’s calcination facility, in Light Metals, pp. 157–162 (2011)
B. Petersen, et al., Application of optimized energy efficient calcination—configuration to AOS stade CFB calciners, in 9th International Alumina Quality Workshop, pp. 371–374 (2012)
K. Yamada, et al., Development of fluid calciner with suspension preheaters, in Light Metals, pp. 159–172 (1983)
A. Pinoncely, K. Tsouria, FCB flash calciner–10 years of experience, in Light Metals, pp. 113–120 (1995)
R. Wischnewski, et al., Alunorte global energy efficiency, in Light Metals, pp. 179–184 (2011)
B.E. Raahauge, et al., Energy saving production of alumina with gas suspension calciner, in Light Metals, pp. 173 (2011)
H.W. Schmidt, et al., Practical experience with operation of Lurgi/VAW—fluid-bed calciners, in Light Metals (1976)
H.W. Schmidt, et al., Alumina calcination with the advanced circulating fluid bed technology, in Light Metals, pp. 129–135 (1996)
W.J. Borer, H. Günthard, Lattice energy, lattice constant, and thermodynamic properties of γ–Al2O3. Halvetica Chim. Acta 53(Face.5), 119–120, 1043–1050 (1970)
T. Yokokawa, O.J. Kleppa, A calorimetric study of the transformation of some meta stable modifications of alumina to get to α–Al2O3. J. Phys. Chem. 68(11), 3246 (1964)
B.E. Raahauge, Thermal energy consumption in gas suspension calciners, in ICSOBA (2017)
D. Kunii, O. Levenspiel, Fluidization Engineering, 2nd edn (Butterworth-Heinemann Series in Chemical Engineering, 1991)
L. Perander, et al., Circo CalTM—Pushing energy efficiency to its limit in circulating fluid bed calcination, in ICSOBA (2012)
L. Perander, et al. Impact of calciner technologies on smelter grade alumina—micro structure and properties, in 8th International Alumina Quality Workshop, pp. 103–107 (2008)
K. Yamada, et al., Dehydration products of gibbsite by rotary kiln and stationary calciner, in Light Metals, pp. 157–171 (1984)
J. Rouquerol et al., Thermal decomposition of gibbsite under low pressure—I. Formation of boehmitic phase. J. Catal. 36, 90–110 (1975)
D.D. Perlmutter, L. Canela, Pore structures and kinetics of the thermal decomposition of Al(OH)3. AIChE J. 32(9) (1986)
L. Rozic et al., The kinetics of the partial dehydration of gibbsite to activated alumina in a reactor for pneumatic transport. J. Serb. Chem. Soc. 66(4), 240–273 (2001)
S.W. Sucech, C. Misra, Alcoa pressure calcination process for alumina, in TMS Light Metals, pp. 119–124 (1986)
Das et al., Thermal decomposition of precipitated fine aluminium trihydroxide. Scand. J. Metall. 33, 211–219 (2006)
V.J. Ingram-Jones, et al., Dehydroxylation sequences of gibbsite and boehmite: study of differences between soak and flash calcination and particle size effects. J. Mater. Chem. 6(1), 73–79 (1996)
B. Wittington, D. Illevski, Determination of the gibbsite dehydration reaction pathway at conditions relevant to Bayer refineries. Chem. Eng. J. 98, 89–97 (2004)
H. Wang, et al., Kinetic modelling of gibbsite dehydration/amorphization in the temperature range 823–923 K. J. Phys. Chem. Solids 67, 2567–2582 (2006)
D. Illevski, New two-stage calcination technology, in 2012, 9th International Alumina Quality Workshop, pp. 364–370 (2012)
S. Wind, B.E. Raahauge, Experience with commissioning new generation gas suspension calciner, in Light Metals, pp. 155–162 (2013)
A. Taylor, Impacts of the refinery process on the quality of smelter grade alumina, in 2005, 7th International Alumina Quality Workshop, pp. 103–107 (2005)
A. Saatci, et al., Attrition behavior of laboratory calcined alumina from various hydrates and its influence on SG alumina quality and calcination design, in TMS Light Metals, pp. 81–86 (2004)
C. Klett, et al., Improvement of product quality in circulating fluidized bed calcination, in Light Metals, pp. 33–38 (2010)
L. Perander, et al., Reducing particle breakage in alumina calcination, in IBAAS-CHALIECO International Symposium 2013 Proceedings, pp. 65–70 (2013)
L. Perander, et al., Coal gasification and impacts on alumina CFB design, in Proceedings of the 10th International Alumina Quality Workshop pp. 243–250 (2015)
B.E. Raahauge, J. Nickelsen, Industrial prospects and operational experience with 32 mtpd stationary alumina calciner, in Light Metals, pp. 81–104 (1980)
S.C. Libby, Decrepitation of calcined abrasive grade bauxite, Moengo, Surinam, in Light Metals (1980)
N. Brown, T. J. Cole, The behavior of sodium oxalate in Bayer alumina plants, in Light Metals, pp. 105–118 (1980)
B.E. Raahauge, et al., Application of gas suspension calciner in relation to Bayer hydrate properties, in The Australasian Institute of Mining and Metallurgy, 1981 Annual Conference, Sydney NSW (1981)
B.E. Raahauge, et al., Energy saving production of alumina with gas suspension calciner, in 111th AIME Annual Meeting, Dallas, US (1982)
S. Wind, C. Jensen-Holm, B.E. Raahauge, Development of particle breakdown and alumna strength during calcination, in Proceedings of the 9th International Alumina Quality Workshop, 2012.
B.E. Raahauge, N. Devarajan, Experience driven design improvements of gas suspension calciners, in 11th Alumina Quality Workshop International Conference (2018)
S. Lindsay, Attrition of alumina in smelter handling and scrubbing systems, in Light Metals, pp. 163–168 (2011)
W.L. Forsyth, W.R. Hertwig, Attrition characteristics of fluid cracking catalyst. Ind. Eng. Chem. 1200–1206 (1949)
J.D. Zwicker, The generation of fines due to heating of aluminium trihydrate, in Light Metals, pp. 373–395 (1985)
J.V. Sang, Factors affecting the attrition strength of alumina products, in Light Metals, pp. 121–127 (1987)
J.E. Lopez, I. Quintero, Evaluation of agglomeration stage conditions to control alumina and hydrate particle breakage, in Light Metals, pp. 199–202 (1992)
P. Clerin, V. Laurent, Alumina particle breakage in attrition test, in Light Metals, pp. 41–47 (2001)
S. Chandraskar, et al., Alumina fines’ journey from cradle to grave, in Proceedings of the 7th International Alumina Quality Workshop (2005)
Rio Tinto—Alcoa Media Release 10 May 2018
Acknowledegements
The author is thankful to all those former colleagues at FLSmidth, who over more than 40 years have contributed with their dedicated and hard work has made the development, commercialization, and commissioning of the Gas Suspension Calcination technology for alumina possible.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2022 The Editor(s) (if applicable) and The Author(s), under exclusive licence to Springer Nature Switzerland AG
About this chapter
Cite this chapter
Raahauge, B.E. (2022). Production of Smelter Grade Alumina (SGA) by Calcination. In: Raahauge, B.E., Williams, F.S. (eds) Smelter Grade Alumina from Bauxite. Springer Series in Materials Science, vol 320. Springer, Cham. https://doi.org/10.1007/978-3-030-88586-1_10
Download citation
DOI: https://doi.org/10.1007/978-3-030-88586-1_10
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-88585-4
Online ISBN: 978-3-030-88586-1
eBook Packages: Chemistry and Materials ScienceChemistry and Material Science (R0)