Hyperfine Interact (2014) 224:131–135 DOI 10.1007/s10751-013-0856-z Comparison of methods to obtain ash from coal of the Southwest of Colombia G. Medina · J. A. Tabares · G. A. Pérez Alcazar · J. M. Barraza Published online: 27 March 2013 © Springer Science+Business Media Dordrecht 2013 Abstract The method for concentration of mineral matter at low temperature (about 250 ◦ C), called Low Temperature Ash (LTA) was applied to a sample of coal from the mine “Las Mercedes” located in Colombia southwestern. This method provides better information about the content of mineral matter in natural coal (NC), removing the organic matter more efficiently without significant transformations of mineral phases present in that coal. These results were observed through Mössbauer spectra and X-ray patterns taken from samples of NC, (LTA) and the conventional method of High Temperature Ash (HTA). The results show that the LTA process provides more representative data of the mineral phases for natural coal than that using the conventional HTA process. Keywords Ash · Mineral · Organic · Phases 1 Introduction Most of the minerals found in natural coal and in residuals from its combus- tion known as ashes, contain Fe as its more important component, which makes Mössbauer spectroscopy a suitable technique to obtain information on the main phases present in coal such as Siderite (S), Pyrite (P), Illite (I) and Jarosite (J) [1, 2]. Proceedings of the Thirteenth Latin American Conference on the Applications of the Mössbauer Effect, (LACAME 2012), Medellín, Colombia, 11–16 November 2012. G. Medina (B ) Departamento de Física, Grupo de nuevos sólidos (GINSAI), Universidad Autónoma de Occidente, A. A. 2790, Cali, Colombia e-mail: gmedina@uao.edu.co J. A. Tabares · G. A. Pérez Alcazar Departamento de Física, Grupo GMTF, Universidad del Valle, A. A. 25360, Cali, Colombia J. M. Barraza Escuela de Ingeniería, Universidad del Valle, A. A. 25360, Cali, Colombia