Chemical treatment of coal by grinding and aqueous caustic leaching

The aim of this work has been to point out the possibility of using GACL process for chemical cleaning of brown coal Novلky (Slovakia) and Pittsburgh No. 8 coal. Simultaneous grinding and aqueous chemical leaching, which is the principle of the process, reduces the inorganic and inorganic sulfur content in both coals. Dearsenification nearly up to 96% is detected in GACL-treated samples of Novلky coal. The possibility of enhancing the recovery of humic acid as a consequence of GACL treatment is demonstrated. The process under study works under atmospheric pressure, temperature of 90°C and NaOH consumption, which is six times lower compared with the MCL process. Further research is needed to minimize the wear of grinding media and to improve the washing step.