Abstract
In this study, ethanol (C2H5OH) was used as an alternative reducing agent for Bi2O3 because ethanol is renewable, increasingly available, and low in toxicity. Thermodynamic analysis was performed to predict experimental conditions for Bi formation in the Bi2O3-C2H5OH-Ar system at Ar/C2H5OH molar ratio of 10.5. Ar was used as a carrier gas for ethanol. Bi2O3 reduction kinetics was investigated at 600 K to 800 K (327 °C to 527 °C) at Ar flow rate 85 sccm. Ar flow rate was also varied at 600 K and 800 K (327 °C and 527 °C) in order to clarify the mechanism controlling the process. Mass measurements and XRD analyses were carried out to determine the extent of reduction. Fractional conversion increased with time and temperature. Full reduction time decreased from ~180 minutes at 600 K (327 °C) to ~30 minutes at 700 K and 800 K (427 °C and 527 °C). The reduction process was external mass transfer limited (Q a = 7.2 kJ/mole) above 700 K (427 °C). It was controlled by intrinsic chemical kinetics (Q a = 54.7 kJ/mole) below 700 K (427 °C). In the mass-transport-controlled regime, the extent of reduction increased with flow rate as predicted by a mass-transport theory. Possible reaction pathways were discussed using the thermodynamic and experimental results.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
F. Habashi: Handbook of Extractive Metallurgy - Volume: II, p. 845–62, VCH Verlagsgesellschaft, Weinheim, 1977.
B.V.R. Raja: Metalworld, 2009, vol. September, pp. 21–26.
[3] K.V. Manukyan, A.G. Avetisyan, C.E. Shuck, H.A. Chatilyan, S. Rouvimov, S.L. Kharatyan and A.S. Mukasyan: J. Phys. Chem. C, 2015, vol. 119, pp. 16131−8.
[4] F. Chen, Y. Mohassab, T. Jiang and H.Y. Sohn: Metall. Mater. Trans. B, 2015, vol. 46B, pp. 1133–45.
[5] G. Eriksson: Chem. Scr., 1975, vol. 8, pp. 100–3.
M.W. Chase, C.A. Davies, J.R. Downey, D.J. Frurip, R.A. McDonald and A.N. Syverud: J. Phys. Chem. Ref. Data, vol. 14 (Suppl.1), 1985.
[7] I. Barin: Thermochemical Data of Pure Substances, VCH Verlagsgesellschaft, Weinheim, 1993.
[8] O. Knacke, O. Kubaschewski and K. Hesselmann: Thermochemical Properties of Inorganic Substances, 2 nd ed., Springer-Verlag Berlin, Heidelberg, 1991.
T.M. Besmann: Report No. ORNL/TM-5775, Oak Ridge National Laboratory, Oak Ridge, 1977.
[10] J.M. Criado, A. Ortega, C. Real and E. Torres De Torres: Clay Min., 1984, vol. 19, pp. 653–61.
[11] B.S. Kim, J.C. Lee, H.S. Yoon and S.K. Kim: Mater. Trans., 2011, vol. 52, pp. 1814–7.
[12] B.S. Kim, E.Y. Kim, H.S. Jeon, H.I. Lee and J.C. Lee: Mater. Trans., 2008, vol. 49, pp. 2147–52.
J. Szekely, J.W. Evans and H.Y. Sohn: Gas-Solid Reactions, Academic Press, New York, 1976
[14] J.E. House: Principles of Chemical Kinetics, 2 nd ed., Academic Press, Burlington, 2000.
[15] H.Y. Sohn and S. Won: Metall. Trans. B, 1985, vol. 16B, pp. 831–9.
G.H. Geiger and D.R. Poirier: Transport Phenomena in Metallurgy, Addison-Wesley Publishing Company, Reading, 1973.
Acknowledgements
This work was partially based on an M.Sc. thesis pursued by F. Korkmaz.
Author information
Authors and Affiliations
Corresponding author
Additional information
Manuscript submitted December 7, 2015
Rights and permissions
About this article
Cite this article
Korkmaz, F., Cetinkaya, S. & Eroglu, S. Thermodynamic Analysis and Reduction of Bismuth Oxide by Ethanol. Metall Mater Trans B 47, 2378–2385 (2016). https://doi.org/10.1007/s11663-016-0686-x
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11663-016-0686-x