TRANSACTION PAPER

A heat transfer model for high titania slag blocks

H. Kotzé^I; P.C. Pistorius^II

^IConsensi Consulting CC, Mthunzini, South Africa
^IICarnegie Mellon University, Pittsburgh, USA. The authors were with the Department of Materials Science and Metallurgical Engineering, University of Pretoria, when this research was performed

SYNOPSIS

Titania slag is used as feedstock in the production of titanium dioxide pigment. It (titania slag) is the product of ilmenite smelting, a process whereby ilmenite is reduced at high temperature utilizing anthracite as a reducing agent. Although various slag tapping configurations are employed throughout the ilmenite smelting industry, the method of tapping the slag from the furnace into bell shaped cast steel pots, was the subject of investigation in this study.
The paper describes the formulation of a cooling model used to calculate and subsequently predict the temperature profile of a slag block during its cooling within the various cooling environments of pot cooling, air cooling and water cooling. The model was calibrated against actual internal slag temperature measurements and verified with information obtained from both pilot and industrial scale blocks. The paper concludes with solidification results and their practical implication.

“Full text available only in PDF format”

References

1. Bale, C.W., Chartrand, P., Degterov, S.A., Eriksson, G., Hack, K., Ben Mahfoud, R., Melancon, J., Pelton, A.D., and Petersen, S. FactSage Thermochemical Software and Databases. Calphad, vol. 26, 2002. pp. 189-228.         [ Links ]

2. Holman, J.P. Heat Transfer. McGraw Hill Book Co, SI Metric Edition, 1989. p. 635.         [ Links ]

3. Holman, J.P. Heat Transfer. McGraw Hill Book Co, SI Metric Edition, 1989. pp. 331-345.         [ Links ]

4. Klinzing, W.P., Rozzi, J.C., and Mudawar, I. Film and transition boiling correlations for quenching of hot surfaces with water sprays. J. Heat Treating, vol. 9, 1992. pp. 91-103.         [ Links ]

5. Mudawar, I. and Valentine, W.S. Determination of the local quench curve for spray cooled metallic surfaces. J. Heat Treat, vol. 7, 1989. pp. 107-121.         [ Links ]

6. Tran, T., Solnordal, C., and Nexhip, C. Determination of thermal conductivity of titania slags. Unpublished CSIRO Minerals Report, DMR-2229, June 2003.         [ Links ]

7. Pistorius, P.C. and Kotzé, H. The link between solidification of high-titania slag and subsequent comminution. Molten 2009, Proceedings of the VIII International Conference on Molten Slags, Fluxes and Salts, Santiago, Chile, January 2009; M. Sanchez, R. Parra, G. Riveros and C. Diaz (eds.). Gecamin, Santiago, Chile. 2009. pp. 51-60.         [ Links ]

8. Handfield, G. and Charette, G.G. Viscosity and structure of industrial high Tio2 slags. Canadian Metallurgical Quarterly, vol. 10, no. 3, 1971. pp. 235-243.         [ Links ]