Characteristics of the HGI Fractions of the Indian Coal Blended with Imported Coals

Abstract

The blends of a high ash Indian coal with three coals of different foreign origins -Australia, Russia and Indonesia weresubjected to HGI testing as per ASTM D 409 and the resulted fractions obtained in the coarser and finer portions of ASTM200 mesh (75 microns) were assessed for their characteristics in respect of proximate and ultimate parameters, alphaquartz and combustion reactivity. The similar studies were also carried out for the parent coals. HGI values were foundadditive in case of Indian-Indonesian coal blends and the same was found non-additive in respect of Indian-Russian andIndian-Australian coal blends. Considerable variation in properties was observed in the coarser and finer fractions of theASTM 200 mesh for parent Indian and Indonesian coals compared to parent Australian and Russian coals. This indicatesthe disproportion of the coals and coal blends particles during the sieving process after subjecting to HGI test. The variationof alpha quartz content in the coarser and finer fractions indicate that there is a segregation of free minerals in the coarserand finer fractions. The conversion plots obtained through TGA for the coarser and finer fractions indicate that there is nomaceral segregation.