Optimization of Operational Practices to Increase the Working Life of Crucibles for Molten Aluminium Transportation

M. A. L. Braulio1, J. B. Gallo1, A. P. Luz2, P. M. Braga3, V. C. Pandolfelli4

1 Alcoa Aluminio S.A. Poços de Caldas, MG, 37719-900/Brazil
2 Federal University of São Carlos (GEMM), (FIRE Associate Laboratory) São Carlos, SP, 13565-905/Brazil
3 Alcoa Aluminio S.A. Poços de Caldas, MG, 37719-900/Brazil
4 Federal University of São Carlos (GEMM), (FIRE Associate Laboratory) São Carlos, SP, 13565-905/Brazil

Revision 02.01.2015, 02.02.2015

Volume 7, Issue 2, Pages 105 - 110


This work addresses various aspects that affect the refractory lining performance of crucibles, as they play an important role in the aluminum production process by conveying molten metal from electrolytic cells (pots) to holding furnaces. Based on a systemic approach, the main objective of this investigation was to increase the working life of these crucibles and, consequently, reduce costs associated to aluminum production and refractory maintenance. According to practical results, the optimization of operational practices (i.e., castables’ processing, placing, pre-heating of the lining, etc.) led to a significant increase (up to 83 %) in the average refractory working life. Moreover, after implementing the identified improvements, 91 % of the available crucibles were able to perform more than 400 metal runs and the maximum number of working cycles per equipment changed from 467 to 715. Therefore, in addition to the increase in the availability of crucibles, the enhanced performance of the refractories also resulted in financial benefits, reducing 47 % of the annual maintenance and pre-heating costs related to these materials.


crucible, refractory maintenance, pre-heating


[1] Internal Maintenance Report – Alcoa – Poços de Caldas – Brazil, (2010) 15–55 (in Portuguese) [2] Nash, W.A.: Resistance of materials. 2nd Ed. Rio de Janeiro 1982, 521 [3] Innocentini, M.D.M.; Cardoso, F.: Dewatering refractory castables. Amer. Ceram. Soc. Bull. 83 (2004) 9101–9108 [4] Lee, W.E.; et al.: Castable refractory concretes. Int. Mater. Rev. 46 [3] (2001) 145–167 [5] Siljan, O.J.; Schoning, C.: Refractories for molten aluminium contact. Part II: Influence of pore size on aluminium penetration, In: UNITECR’ 01, Proc. Unified Int. Tech. Conf. on Refractories. Cancún, Mexico (2001), 551–571 [6] Rahaman, M.N.: Ceramic processing and sintering. New York 1995, 770 [7] Bernardes, R.: Inspection and installation of refractories – Short course. Rio de Janeiro 2001, 94 (in Portuguese) [8] Lafraka, J.R.B.: Manual of reliability, maintainability and availability. Rio de Janeiro 2001, 374 (in Portuguese) [9] Keey, R.B.: Moisture in gases and solids. In: Introduction to industrial drying operations. London 1978, 15–50 [10] Innocentini, M.D.M.; et al.: Vaporization process and pressure build up during dewatering of dense refractory castables. J. Amer. Ceram. Soc. 86 (2003) [9] 1500–1503 [11] Salomão, R.; Bittencourt, L.R.M.; Pandolfelli, V.C.: Drying additives for refractory castables: aluminum powder and polymeric fibers. Cerâmica 54 (2008) 259–267 (in Portu- guese) [12] Oda, K.; et al.: Drying characteristic of highdense castable. Taikabutsu Overseas 13 (1989) [2] 21–28 [13] Cardoso, F.A.; et al.: Scale-up effect on the drying behavior of high-alumina refractory castables. J. Tech. Assoc. Refr. Japan 23 (2003) [4] 226–230 [14] Universidade Estadual de Campinas – UNICAMP. Faculty of Mechanical Engineering, Department of Thermal and Fluid Engineering. IM351 – Combustion Technology. Campinas 2006, 25 (in Portuguese) [15] Cmp Techcommentary, Electric ladle preheaters. Pittsburg, EPRI Center for Metals Production 1988, 4 [16] Techapplication, Electric resistance ladle preheating improves foundry operations. Pittsburg: EPRI Center for Materials Production – CMP 079 (1992) 5 [17] American Society for Testing and Materials - ASTM. Annual book of ASTM Standards. Philadelphia (1995), 576. Vol. 15.01: Refractories; carbon and graphite products; activated carbon


Göller Verlag GmbH