Acta Montanistica Slovaca (Nov 2010)
Preparation of low-ash products from Slovak sub-bituminous coals – a material balance
Abstract
The fines of sub-bituminous coals from the Cígeľ and the Handlová Collieries in use as steam coal in coal-fired power plant weresubjected to washing in a water-only cyclone (WOC) with the aim to obtain suitable input material for organic compounds extraction.The WOC with a diameter of 150 mm and a cone part consisting of three angle sections 135°-75°-20° was applied. Vortex finder (overflow)and spigot (underflow) diameters were of 68 mm and 14.6 mm, respectively. Two basic products overflow and underflow were obtained.The third one, slurry or circulating charge was also considered into total material balance of washing. Thus, the contents of ash,combustible matter, SiO2, Al2O3, CaO, MgO, FeTOTAL, STOTAL, SSULPHIDIC and As were determined in the products of washing. Subsequently,on the basis of analyses the recoveries of individual components into products of washing were calculated. The washing resultedin the obtaining of significantly deashed coal at the overflow of WOC. In such way a washed coal with ash content in dry basis of 6.99 %at a mass yield of 20.74 % was won in the case of coal from the Cígeľ Colliery. Similarly, in the case of coal from the Handlová Colliery andits eastern field the products with ash content in dry basis of 7.70 % and 9.01 % at mass yield of 29.37 % and 29.50 % were obtained.Finally, the washing resulted in over 90 % ash rejection and about 70 % total sulphur rejection.
