Wet Beneficiation Characteristics of Indian Bituminous Coal with Low Cost Choline Chloride based Deep Eutectic Solvents

Abstract

ABSTRACT The current study reports the dissolution of three Indian Bituminous coals with low-cost Deep Eutectic Solvents (DES) prepared by an equimolar addition of Hydrogen Bond Donor (HBD)(Choline Chloride) and Hydrogen Bond Acceptor (HBA)(Ethylene Glycol/Urea/Glycerol). The synthesized solvents were, namely, Choline chloride with Ethylene glycol [ChCl][EtGl], Choline Chloride with Glycerol [ChCl][Gl] and Choline Chloride with Urea [ChCl][Urea]. These are then subsequently used for wet beneficiation and swelling experiments where values ranging from 1.02 to 1.2 were reported. [ChCl][Urea] was found to have the highest swelling ratio for all the coal variants. The oxygen-containing functional groups were seen to decrease after the beneficiation experiments especially with [ChCl][Urea]. Morphological studies of the samples were also carried out which confirmed the disintegration or reduction of coal particles in DES’s. [ChCl][Urea] was the most effective in carrying out the disintegration of coal particles from 500 µm into approximate 50 µm sized particles. The carbon content of Coal 2 after its pre-treatment with [ChCl][Urea] increased by approximately 4%, i.e. from 45.5%(raw) to 49%(pretreated). The extract yield was found out to be 19.3% for the bituminous variety in [ChCl][Urea]