Kinetics of Sulcis coal chemical cleaning process

Sulcis coal is a sub-bituminous coal from the Monte Sinni mine in the South West coast of Sardinia. The ash content of this coal is about 15 wt % as received, whereas the sulphur content is 6-7 wt% (inorganic sulphur is present at about 2-3 wt%). Since most of the pyritic sulphur is finely disseminated in crystals of micron or sub-micron size, the only remaining possibility of removing sulphur from this coal prior to its utilization is confined to chemical methods. The present work shows the results of the experimental testes which are conducted on Sulcis coal samples by sequential leaching of potassium hydroxide followed by hydrogen peroxide. Moreover, the present paper shows the kinetics of Sulcis coal leaching process. The high efficiency of sulphur reduction, on average about 30 %, was found to be of special technical relevance for relatively large particle sizes, <5.60 mm, said efficiency being obtained through tests carried out on different particle size classes of leached samples.