Demineralization and Characterization of Coal Deposit Found in Maiganga, Akko Local Government, Gombe State, Nigeria

Abstract

The characterization of coal provides valuable information on its composition, environmental effects, and applications. This study investigates the leachate elemental composition, physicochemical properties, morphology, mineralogy, functional groups, and thermal behaviour of the demineralised and demineralized coal deposits in Maiganga, Gombe State. Three modes of coal demineralization including mixed acid-alkali, acid, and alkali demineralization were tested. The quantified carbon indicates the hierarchy of leachates in order; HCl+ NaOH Washed > NaOH Washed> HCl Washed (70.38%>64.42%>60.39%). The microstructure images showed crystallites on the coal matrix indicating the presence of mineral phases found abundant in the demineralised sample compared to the demineralized coal. Also, the compositions of demineralised coal appeared in oxide form while that of demineralized coal is elemental because the chemical treatment effects during demineralization dissolute the oxides. The FTIR spectra demonstrate different aliphatic –CH bonds in both samples indicating the Maiganga coal as sub-bituminous coal with high carbon content. The phases in the demineralised coal sample are SiO2, PbCO3, CaO, and Mg2Al2SiO5(OH)4 and for the demineralized sample, the phases are Ca4I8 O24, SiO2 and PbCO3. For efficient high-energy recovery the temperature of >848.2 oC is required as demonstrated by the two samples in thermal analysis, the Temperature Profile Characteristics (TPC) for the samples differ. Furthermore, the comprehensive combustion characteristics parameters indicated a higher and better combustion performance by the demineralized coal (2.4 x10-7 min-2 C-3) compared to the undemineralized coal (1.0 x10-9 min-2 C-3) sample. This finding demonstrated that mining the Maiganga coalfield may not pose threats to humans and the environment, and the coal is suitable for electricity generation.