Upgradation of coal by froth flotation method; A case study of Akkakhel, Akhorwal and Shekhan coal mines
Keywords:
Desulfurization, Ash removal, fixed carbon, GCV, Coal, Froth flotation.Abstract
This study has been carried out on the upgradation of low-grade coals of Akkakhel, Akhorwal
and Shekhan areas in western Khyber Pakhtunkhwa, Pakistan. The coals of these areas, because of high ash
and sulfur contents and low Gross Calorific Values (GCV) are being mined on small scale for domestic
purposes only. In this work, attempts have been made to reduce sulfur and ash contents from high ash and
sulfur coal which will ultimately increase the fixed carbon and GCV of the studied coal from aforementioned
coal mines by froth flotation technique. During this technique, the use of kerosene as a collector and pine oil
as a frother at various particle sizes (i.e., -80, -100 and -140 mesh) has decreased ash and sulfur contents in the
studied coal samples. The optimum process parameters were established at -140 mesh particle size with 20 %
solids in floation pulp at pH 9. Under these conditions ash was reduced from 40.6 to 13.8% (66 % reduction)
and sulfur from 3.97 to 1.51% (62 % reduction) while the GCV was enhanced from 7070 to 7963 kcal/kg in
the coal samples of Akkakhel area. In the coal samples of Akhorwal area, ash was reduced from 35 to 18.16%
(48.11% reduction) and sulfur from 6.31 to 3.51% (44.37% reduction) while the GCV was enhanced from
5500 to 6108 kcal/ kg. Similarly, in the coal samples of Shekhan area, ash was reduced from 41.6 to 20.1%
(51.68% reduction) and sulfur from 3.1 to 1.5% (51.61% reduction) while the GCV was enhanced from 3995
to 4941 kcal/ kg. The final upgraded product was found suitable for use in power plants, boilers, and cement
industries etc.
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