Boletín de Ciencias de la Tierra
Print version ISSN 0120-3630
GOMEZ ROJAS, OLGA PATRICIA; CARMONA LOPEZ, INÉS and BUSTAMANTE RUA, OSWALDO. ANALYSIS OF LIBERATION OF THE GROUPS OF MACERALES OF THE COAL: COLOMBIAN COALS. Bol. cienc. tierra [online]. 2007, n.21, pp. 75-86. ISSN 0120-3630.
Three coal seams of different Carboniferous Zones from Colombia were selected with the intention of evaluating the degree of liberation of the macerals groups. The method used in the studies mineral liberation of the hard rock was followed. The analyzed samples correspond to coals of the Carboniferous Zones of La Guajira, Antioquia, and Boyacá, the analysis of liberation of the macerals was based on the results of the petrography analysis (determination of the percentage of free macerals and particles with mixed composition) of the samples with grain size mesh 230, 270, 325 and 400. During the pulverize the macerals groups in the coal present a tendency to the increase of free components. The liberation is not delimited at intervals of size, as usually happens in the minerals, the sizes oscillates between 5 and 350 microns for the liptinites and between 5 and 504 microns for the inertinites. The forms, sizes and associations (microlithotypes) that present the different groups from macerals, define the proportions of component free and mixed. The group maceral that presents greater probability of being frees is the vitrinite, because it is the maceral that is in greater proportion, this is demonstrated in the dominion of microlithotype vitrite in the different samples; the second group is the inertinite specially for the coals of Boyacá and La Guajira, the distribution of size and form of presentation of the macerals of the group of the inertinite (particle tissues) help their liberation. The liptinites by their association with the vitrinite and its low proportion in coals of Boyacá and La Guajira only present a significant degree of liberation in the sample of Antioquia. In order to receive a greater rank of liberation of the components it is necessary to take inferior coals to grain size a to 10 microns.
Keywords : Coal; Macerals; Liberation.