Occurrence and distribution of metals and porphyrins in ...
2007-12-1 · The metal contents of Nigerian coal minerals were analyzed using an atomic absorption spectrophotometer. Calcium, Na and Fe occurred as major elements with concentrations ranging from 9782 μg/g for Ca to 432 μg/g for Na, whereas K, Mg, Mn, Ni, Cr, Zn, Pb and Cu, which occurred at trace levels ranged from 673.73 μg/g for Mg to 2.97 μg/g for Mn.