Sulphide oxidation in ornamental slates: protective treatment with siloxanes


  • T. Rivas Universidad de Vigo
  • J. Iglesias Universidad de Vigo
  • J. Taboada Universidad de Vigo
  • J. A. Vilán Universidad de Vigo



pyrrhotine, sulphide oxidation, silanes-siloxanes, slates, ornamental rocks


In this work, we present the results of the measurement of the effectiveness of two silanes-siloxanes based products applied on roofing slates with the aim of slowing down the oxidation of the iron sulphide inclusions. The products were applied by immersion and spraying and also at different dilutions. The effectiveness of the treatments were evaluated by means of static contact angle measurements and water absorption coefficient variations; also, the durability under thermal cycles and the colour variations before treatment and before UVA exposition were tested. In all the cases, a very low product consumptions were obtained, due to the particular porous system of these rocks; also, any of the treatments increased the static angle. Nevertheless, the products tested remarkably increased the resistance of sulphides to the oxidation during thermal cycles without producing important changes in rock colour and also they have shown a good durability under UVA exposition


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(1) Blanco, M.; Taboada Castro, J.; Martínez-Alegría López, R.: “Incidencia de las características mineralógicas y texturales en algunas propiedades de las pizarras de techar”, Cuadernos del Laboratorio Xeolóxico de Laxe, vol. 14 (1989), pp. 247-254.

(2) García-Guinea, J.; Lombardero, M.; Roberts, B.; Taboada, J.; Peto, A.: “Mineralogía y microestructura de la pizarra de techar: comportamiento termoóptico y fisilidad”, Mater. Construcc., vol. 48, nº 251 (1998), pp. 37-48. doi:10.3989/mc.1998.v48.i251.470

(3) Cárdenes, V.; Lombardero, M.; García-Guinea, J.: “Factores de calidad en la elaboración de placas de pizarra para cubiertas en Galicia y León”, Roc Máquina, vol. 67 (2001), pp. 90-98.

(4) García-Guinea, J.; Cárdenes, V.; Lombardero, M.: “Determination of iron sulphides in roofing slates from the north west of Spain”, Mater. Construcc., vol. 52, nº 266 (2002), pp. 55-63.

(5) Rimstidt, J. D.; Vaughan, D. J.: “Pyrite oxidation: a state of the art assessment of the reaction mechanism”, Geochimica and Cosmochimica Acta, vol. 67, nº 5 (2003), pp. 873-880. doi:10.1016/S0016-7037(02)01165-1

(6) Descostes, M.; Mercier, F.; Beaucaire, C.; Zuddas, P.; Trocellier, P.: “Nature and distribution of chemical species on oxidized pyrite surface: complementary of XPS and nuclear microprobe analysis”, Nuclear Instruments and Methods in Physics Research B, vol. 181 (2001), pp. 603-609. doi:10.1016/S0168-583X(01)00627-9

(7) Descostes M.; Vitorge, P.; Beaucaire, C.: “Pyrite dissolution in acidic media”, Geochimica et Cosmochimica Acta, vol. 68, nº 22 (2004), pp. 4559-4569. doi:10.1016/j.gca.2004.04.012

(8) Evangelou V. P.: “Pyrite microencapsulation technologies: Principles and potential field application”, Ecological Engineering, vol. 17 (2001), pp. 165-178. doi:10.1016/S0925-8574(00)00156-7

(9) Zhang, X.; Borda, M. J.; Schoonen, M. A. A.; Strogin, D. R.: “Pyrite oxidation inhibition by a corss-linked lípido coating”, Geochem. Trans., vol. 4, nº 2 (2003), pp. 8-11. doi:10.1186/1467-4866-4-8 doi:10.1186/1467-4866-4-8 PMCid:1475633

(10) Kargbo, D. M.; Atallah, G.; Chatterjee, S.: “Inhibition of pyrite oxidation by a phospholipid in the presence of silicate”, Environ. Sci. Technol, vol. 38 (2004), pp. 3432-3441. doi:10.1021/es0352552. doi:10.1021/es0352552

(11) Elsetinow, A. R.; Borda, M. J.; Schoonen, M. A. A.; Strongin D. R.: “Suppression of pyrite oxidation in acidic aqueous environments using lipids having two hydrophobic tails”, Advances in Environmental Research, vol. 7 (2003), pp. 969-974. doi:10.1016/S1093-0191(02)00101-6

(12) Chen, Y. W.; Li, Y.; Cai, M. F.; Belzile, N.; Dang, Z.: “Preventing oxidation of iron sulphide minerals by polyethylene polyamines”, Minerals Engineering, vol. 19 (2006), pp. 19-27. doi:10.1016/j.mineng.2005.04.007

(13) Lewin, S. Z.; Charola, A. E.: “Stone decay due to foreign inclusions”, Proc. Int. Symp. The Conservation of Stone, Bologna (1981), R. Rossi Manaresi (ed.), vol. 2, pp. 205-217.

(14) Delgado, J.; Costa, D.; Ferreira, A. P.: “Assessment of the effectiveness and harmfulness of water repellents on granite”, Proc. III Int. Symp. Conservation of Monuments in the Mediterranean Basin, Venice (1994), V. Fassina, H. Ortz and F. Zezza (eds.), pp. 883-890.

(15) Rivas, T.; Silva, B.; Prieto, B.: “Medida de la eficacia de dos hidrofugantes aplicados a rocas graníticas”, Mater. Construcc., vol. 48, nº 249 (1998), pp. 5-21. doi:10.3989/mc.1998.v48.i249.483

(16) Berardi, E.; Mecchi, A. M.; Calia, A., Lettieri, M.: “Water-repellent treatments on some calcareous Apulian stones of differing porosity”, Proceedings of 5th International Symposium on the Conservation of Monuments in the Mediterranean basin, Seville, Spain (2002), pp. 401-406.

(17) Íñigo, A. C.; Vicente-Tavera, S.; Rives, V.: “Statistical design applied to hydric property behaviour for monitoring granite consolidation and/or water-repellency treatments”, Mater. Construcc., vol. 56, nº 281 (2006), pp. 19-30.

(18) De los Santos, D.; Rivas, T. B.; Prieto, P. Sanmartín: “Different behaviour of TEOS-based consolidant applied to granite and to biocalcareous sandstone”, International Symposium on Stone Consolidation in Cultural Heritage-research and practice. Acces, research and Technology for the conservation of the European Cultural Heritage Eu-ARTECH (org.). Lisbon, 06/07/2008-07/07/2008.

(19) Álvarez de Buergo, M.; Fort González, R.: “Basic methodology for the assessment and selection of water-repellent treatments applied on carbonic materials”, Progress in Organic Coatings, vol. 43 (2001), pp. 258-266. doi:10.1016/S0300-9440(01)00204-1

(20) Tsalakof, A.; Manoudis, P.; Karapanagiotis, I.; Chryssoulakis, I.; Panayiotou, C.: “Assesment of synthetic polymeric coatings fot the protection and preservation of stone monuments”, Journal of Cultural Heritage, vol. 8 (2007), pp. 69-72. doi:10.1016/j.culher.2006.06.007

(21) Brugnara, M.; Degasperi, E.; Della Volpe, C.; Maniglio, D.; Penati, A.; Siboni, S.; Toniolo, L.; Poli, T.; Invernizzi, S.; Castelvero, V.: “The application of the contact angle in monuments protection: new materials and methods”, Colloids and Surfaces A: Physicochem. Eng. Aspects, vol. 241 (2004), pp. 299-312. doi:10.1016/j.colsurfa.2004.04.035

(22) Julivert, M.; Fontbote, J. M.; Ribeiro, A.; Conde, L.: Mapa tectónico de la Península Ibérica y Baleares, IGME, Madrid (1972).

(23) Marcos, A.: “Las series del Paleozoico inferior y la estructura herciniana del occidente de Asturias (noroeste de España)”, Trabajos de Geología de la Universidad de Oviedo, vol. 6 (1973), pp. 3-113.

(24) Pérez Estaun, A.: “Estratigrafía y estructura de la rama sur de la zona asturoccidental-leonesa”, Memorias del IGME, vol. 92 (1978), Madrid.

(25) Barros, J. C.: “Nuevos datos geológicos y cartográficos sobre el flanco sur del Sinclinorio de Truchas”, Cuadernos do Laboratorio Xeolóxico de Laxe, vol. 14 (1989), pp. 93-116.

(26) European Committee for Standardization, EN 12326-2 European Standard: Slate and stone products for discontinuous roofing and cladding, part. 2: Test Methods (2000).

(27) International Commission on Illumination, CIE S 014-4/E: 2007 Colorimetry-part 4: CIE 1976 L*a*b* Colour Space, CIE Central Bureau, Vienna (2007).




How to Cite

Rivas, T., Iglesias, J., Taboada, J., & Vilán, J. A. (2011). Sulphide oxidation in ornamental slates: protective treatment with siloxanes. Materiales De Construcción, 61(301), 115–130.



Research Articles