Quantitative Estimation of Major and Trace Elements in Coals of the Benue Trough, Nigeria

Abstract

The concentrations of major and trace elements in ash residues of coals of the Benue Trough, Nigeria have been determined by electron microprobe and laser ablation-inductively coupled plasma-mass spectrometry, respectively. Major and trace element determination in rocks by fusion on an iridium strip heater followed by electron microprobe and laser ablation-inductively coupled plasma-mass spectrometry is extended here to coal ash, and the accuracy of the method is evaluated by including an Argonne Premium Coal reference sample in each analysis program. Si and Al are the major elements detected in the coal ashes. An assessment using worldwide concentration ranges of trace elements in coal ashes indicates that the Benue Trough coal ash residues are enriched in some hazardous trace elements, including Be, V, Co, and Cr. The estimated concentrations of most of the elements in the raw coals are higher than the world averages for coal. The results obtained for the Argonne Premium Coal show very good correlations with the literature and certified values, indicating that the technique described in this study can be routinely used to determine element concentrations in coals.

Keywords:

• Benue Trough
• coal
• electron microprobe
• major elements
• trace elements

Notes

^a Ketris and Yudovich, 2009.

^a Ketris and Yudovich, 2009.

^b UCC = Upper continental crust (Rudnick and Gao, 2003).

^a This study

^b Doughten and Gillison, 1990

^c Briggs, 1987

^d Evans et al., 1990

^e Meier, 1997.