Microscopic and X-ray studies of thermally metamorphosed coals from Takashima colliery, Nagasaki parfecture

Abstract

In this paper are summarised the results of the chemical and physical studies of thermally metamor-phosed coals from the Takashima colliery. For the physical studies, X-ray diffraction. records by the proportional counter diffractometer have been used. The X-ray study had two objects. One was to determine ash minerals in the thermally metamorphosed coal, and the other was to standardize the X-ray diffraction patterns obtained from normal thermally unaffected coals as well as from semi-cokes and cokes. These have been described and discussed in detail. Optical methods have been also applied to this study under the reflecting microscope, and the texture and unisotropic opticall character of the thermally affected coals have been investigated, which revealed that the unisotropic mosaic structure becomes distinct from the stage of semi-coke. The refractive index of the coal of lover grade of carbonization becomes higher as the grade rises.