Characterization and Classification of Coal Using Spectroscopic and Proximate Techniques: A Case Study of Coal from Azagba, Nigeria

Nigeria's coal reserves remain largely underutilizedin contrast to its more extensively developedoil andgas resources. The application potentialofcoal is influencedby its structural and chemical characteristics. This study focuses on the analysis of Azagba coal using various techniques, including X-ray fluorescence (XRF), X-ray diffraction (XRD), proximate and ultimate analyses, and Fourier-transform infrared spectroscopy (FTIR). Inorganic analysis reveals a dominant presence ofSiO3 (53.65%), SO3 (16.18%), and Al2O3 (7.09%), indicating a siliceous composition. XRD analysis confirms a high proportion of graphite crystalline phase (82%) and minerals such as quartz, marialite, and calcite. Key structural indicators—interlayer spacing (d002 = 3.38 Å) and stacking height (Lc = 57.32 nm)—suggest a wellorderedcarbon framework. FTIR spectra further reveal hydroxyl (-OH), aliphatic (C-H), andvarious oxygen-containing groups, with a high aromatic hydrogen ratio (Hal/H= 0.49) andsignificant aromaticity (fa = 0.68). The proximate andultimate analyses classify Azagba coal as a high-rank, volatile bituminous to anthracite type, marked by a high fixed carbon content (59.47%) and low ash content (1.13%). These attributes emphasize the coal's structural maturity, reactivity potential, and industrialapplicability