Abstract
Density of twelve Japanese coals and five foreign coals including wide range of carbon content were measured with methanol, n-hexane and mercury as replacing liquids.
Discussion was done about pore volume of coals from both densities including helium densities (measured by Fujii et al.) and adsorption of carbon dioxide interpreted by Dubinin-Polanyi's equation.
Densities with methanol are the highest in all the coals investigated except a few coals, difference of which are considered to be experimental error.
Apparent excess of methanol densities from helium densities were too large to interprete it ascontraction or adsorption effects of methanol in pore structure of coals.
It was suggested that its excess result from both activated diffusion effect of helium molecules to coal structure and opening of closed pores by swelling effect of methanol.
It was concluded from the data of the pore volume of coals calculated frodensity, carbon dioxide adsorption and density drift in methanol and in n-hexane that mean pore diameter of coals increase with increasing the rank of coal to about 85% carbon content, reaching maximum, and decrease with increasing the rank of coal.
