Ultra clean coal from polish coal deposits

Ultra clean coal (UCC) contains less than one per cent by weight ash. It is created via chemical leaching, because conventional, physical separating techniques cannot achieve this extremely low mineral content. Potential uses for ultra clean coal, apart from power generation, include for example directly fired into gas turbines – increasing the efficiency of power generation and eliminating the need for ash dams, production of graphite and carbon fibres, wood charcoal alternative for silicon smelting and others. In the paper is presented preparation of UCC from three kinds of Polish coals differing in degree of carbonification. In the study coals ranks of 35.1 (sample A), 33 (sample B) and 31 (sample C), according to the Polish Standards were used. The degree of carbonification was determined on the basis of vitrinite reflectance. Petrographic characteristics was done by investigation of macerals, microlithotypes, carbominerites and minerites distribution. Coal samples were first physically enriched by density separation. Then the enriched portion was chemically demineralized by using the proper leachant. The X-ray investigation of mineral matter before and after leaching were performed too. As leaching agents hydrochloric acid (HCl), hydrofluoric acid (HF) and nitric acid (HNO₃), were used. On the base of the results obtained it was stated that it is possible to get coal of the ash content below 1%.