Multi-element analysis of solutions of coal ash using inductively coupled plasma optical-emission spectrometry

Abstract

A rapid dissolution method and analysis of coal ash using inductively coupled plasma optical-emission spectrometry is described. The calibration and analysis of “unknowns” involved the use of nickel as an internal standard. The most acceptable calibration was obtained using solutions of standard ash and slag materials. The precision for the determination of 11 elements expressed as their oxides is assessed by the analysis of ten replicate digestions of the same coal ash. The results compare favourably with the British Standards Institution (BSI) criteria. Using the procedure described, a five-fold increase in sample throughput is obtained compared with the current BSI method. All the elements are digested completely in 20 min and only sulphur is unstable if digestion periods in excess of 2 h are used. The method is ideally suited to cover the normal concentration levels for the major and minor elements present in coal or coke ash. It should also be adaptable for the determination of trace elements (except nickel) in coal ashes.