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Thermally induced transformations of Fe oxide-stabilized residues from waste incineration

Published online by Cambridge University Press:  05 July 2018

M. A. Sørensen*
Affiliation:
Environment and Resources DTU, Technical University of Denmark, Build. 115, 2800 Kgs. Lyngby, Denmark
C. Bender Koch
Affiliation:
Chemistry Department, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
*

Abstract

Air pollution control (APC) facilities at waste incinerator plants produce large quantities of solid residues rich in salts and heavy metals. Heavy metals are readily released to water from the residues and it has, therefore, been found suitable to apply a rapid co-precipitation/adsorption process as a means to immobilize the toxic elements. In the ‘Ferrox process’, this immobilization is based on co-precipitation with an Fe(III) oxide formed by oxidation of Fe(II) by air in an aqueous slurry with the APC residue at alkaline pH. In this work we have undertaken a Mössbauer spectroscopy study of the Fe oxide phase formed by precipitation at room temperature and of the oxides present after heating to 600 and 900°C. The only Fe oxide observed in the Ferrox product at room temperature is a very poorly crystalline ferrihydrite. Analytical transmission electron microscopy showed that the main elements associated with the ferrihydrite are Si and Ca. Following heating to 600°C the oxide is still characterized as an amorphous Fe oxide, and it is probable that Si associated with the ferrihydrite is decisive in preventing crystallization. After the 900°C treatment a transformation into defect maghemite is observed. Reducing gases produced from carbon in the samples probably induces this transformation. It eases, thus, the reduction of Fe(III) and the consequent formation of magnetite that eventually oxidizes to maghemite during cooling in air.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2001

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References

Bødker, F., Hansen, M.F., Bender Koch, C., Lefmann, K. and Mørup, S. (2000) Magnetic properties of hematite nanoparticles. Phys. Rev. B, 61, 6826–38.CrossRefGoogle Scholar
Campbell, A.S., Schwertmann, U. and Campbell, P.A. (1997) Formation of cubic phases on heating ferrihydrite. Clay Miner., 32, 615–22.CrossRefGoogle Scholar
Carlson, L. and Schwertmann, U. (1981) Natural ferrihydrites in surface deposits from Finland and their association with silica. Geochim. Cosmochim. Acta,, 45, 421–9.CrossRefGoogle Scholar
Childs, C.W., Kanasaki, N. and Yoshinaga, N. (1993). Effect of heating in air on Si- and Ge-containing ferrihydrites. Clay Sci., 9, 6580.Google Scholar
Cornell, R.M. and Schwertmann, U. (1996) The Iron Oxides. VCH, Weinheim, Germany.Google Scholar
Cornell, R.M., Giovanoli, R. and Schindler, P.W. (1987) Effect of silicate species on the transformation of ferrihydrite into goethite and hematite in alkaline media. Clays Clay Miner. 35, 21–8.CrossRefGoogle Scholar
Cornell, R.M., Giovanoli, R. and Schneider, W. (1992) The effect of nickel on the conversion of amorphous iron(III) hydroxide into more crystalline iron oxides in alkaline media. J. Chem. Technol. Biotechnol., 53, 73–9.CrossRefGoogle Scholar
Eighmy, T.T., Eusden, J.D., Krzanowski, J.E., Domingo, D.S., Stämpfli, D.M., Martin, J.R. and Erickson, P.M. (1995) Comprehensive approach towards understanding element speciation and leaching behavior in municipal solid waste incineration electrostatic precip itator ash. Environ. Sci. Technol., 29, 629–46.CrossRefGoogle Scholar
Fermo, P., Cariati, F., Pozzi, A., Lasagni, M., Demartin, F., Tettamanti, M., Collina, E., Lasagni, M., Pitea, D., Puglisi, O. and Russo, U. (1999) The analytical characterization of municipal solid waste incinerator fly ash: methods and preliminary results. Fresenius J. Anal. Chem., 365, 666–73.CrossRefGoogle Scholar
Ford, R.G., Kemner, K.M. and Bertsch, P.M. (1999) Influence of sorbate-sorbent interactions on the crystallization kinetics of nickel- and lead-ferrihydrite coprecipitates. Geochim. Cosmochim. Acta, 63, 3948.CrossRefGoogle Scholar
Giovanoli, R. and Cornell, R.M. (1992) Crystallization of metal substituted ferrihydrites. Z. Pflanzenernäh. Bodenkd., 155, 455–60.CrossRefGoogle Scholar
Glasauer, S.M., Hug, P., Weidler, P.G. and Gehring, A.U. (2000) Inhibition of sintering by Si during the conversion of Si-rich ferrihydrite to hematite. Clays Clay Miner., 48, 51–6.CrossRefGoogle Scholar
Graydon, J.W. and Kirk, D.W. (1992) Characterization of Fly Ash from a Municipal Solid Waste Incinerator. EDP Congress, pp. 327–50 (Hager, J.P., editor). The Minerals, Metals & Materials Society, Warrendale, PA.Google Scholar
Hansen, M.F., Bender Koch, C. and Mørup, S. (2000) Magnetic dynamics of weakly interacting hematite nanoparticles. Phys. Rev. B, 62, 1124–35.CrossRefGoogle Scholar
Kirby, C.S. and Rimstidt, J.D. (1993) Mineralogy and surface properties of municipal solid waste ash. Environ. Sci. Technol., 27, 652–60.CrossRefGoogle Scholar
Lundtorp, K., Jensen, D.L., Sørensen, M.A., Mogensen, E.P.B. and Christensen, T.H. (2001) Treatment of waste incinerator air-pollution-control residues with FeSO4: Concept and product characterizat ion. Submitted to Waste Manag. Res. CrossRefGoogle Scholar
Martínez, C.E. and McBride, M.B. (1998 a) Solubility of Cd2+, Cu2+, Pb2+, and Zn2+ in aged coprecipitates with amorphous iron hydroxides. Environ. Sci. Technol., 32, 743–8.CrossRefGoogle Scholar
Martínez, C.E. and McBride, M.B. (1998 b) Coprecipitates of Cd, Cu, Pb and Zn in iron oxides: Solid phase transformation and metal solubility after aging and thermal treatment. Clays Clay Miner., 46, 537–45.CrossRefGoogle Scholar
Roden, E.E. and Zachara, J.M. (1996) Microbial reduction of crystalline iron (III) oxides: Influence of oxide surface area and potential for cell growth. Environ. Sci. Technol., 30, 1618–28.CrossRefGoogle Scholar
Sørensen, M.A., Bender Koch, C., Stackpoole, M.M., Bordia, R.K., Benjamin, M.M. and Christensen, T.H. (2000 a) Effects of thermal treatment on mineralogy and heavy metal behavior in iron oxide stabilized air pollution control residues. Environ. Sci. Technol., 34, 4620–7.CrossRefGoogle Scholar
Sørensen, M.A., Stackpoole, M.M., Frenkel, A.I., Bordia, R.K., Korshin, G.V. and Christensen, T.H. (2000 b) Aging of iron (hydr)oxides by heat treatment and effects on heavy metal binding. Environ. Sci. Technol., 34, 39914000.CrossRefGoogle Scholar
Sun, T., Paige, C.R. and Snodgrass, W.J. (1996) The effect of cadmium on the transformation of ferrihydrite into crystalline products at pH 8. Water Air Soil Pollut., 91, 307–25.CrossRefGoogle Scholar
Zhao, J., Huggins, F.E., Feng, Z. and Huffman, G.P. (1994) Ferrihydrite surface structure and its effect on phase transformation. Clays Clay Miner., 42, 737–46.Google Scholar