The leaching of chlorine from hard coal: Part I. Relationship between the process parameters and its effectivity

In the study the research potential offered by the Scanning Electron Microscope to investigate into the surface of hard coal for mineral substances, especially of chlorine, was utilized. The identification of such substances – basing upon the resulting X-ray spectra and photographs – allowed one to corroborate the usefulness of further investigation step – viz. leaching. Variable parameters in those investigations were: grain size, leaching temperature, time and leaching cycles. Of great importance for the efficiency of the leaching process is granulation. The smaller the grain of coal, the more chlorine was removed because the opening of pores closed in the process of fragmentation increases the carbon surface available for water molecules.

Research Highlights► Chlorine removal from coal by leaching with demineralized water. ► Particle size, leaching time and temperature affect the amount of chlorine removed. ► Leaching of chlorine should be carried out below 90 °C.