Development of an International Standard for Determining Trace Elements in Coal

There are no international standard methods for the determination of trace elements in coal. One of the coauthors (K.W. Riley) as an Australian representative on the Subcommittee for the analysis of solid mineral fuels, TC 27 SC 5 of the International Organisation for Standardisation (ISO) has stressed the need for accurate and reliable test methods. This lack of accredited standard methods which are capable of providing reliable and accurate data on the levels of environmentally sensitive trace elements in coals has inhibited the establishment of good quality assurance in the specification of the levels of trace elements in internationally traded coals. This can only be addressed by the establishment of more reliable and accurate standard methods which are accepted by both coal suppliers and users, worldwide.

There are a number of national standards which have been developed but many of these have limitations. The early Australian Standard, AS 1038.10.1 (1986) is based on flame atomic absorption spectrometry (AAS) and covered some but not all of the trace elements of concern. This particular instrumental technique lacks the sensitivity to determine lead and cadmium at the concentrations found in the majority of traded coals and generally has poorer reproducibility than that achievable by inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma mass spectrometry (ICP-MS). Apart from the American Society for Testing and Materials (ASTM) provisional standard (PS 52), there are no Standards based on ICP-AES or ICP-MS for the analysis of coals for trace elements.

The results of previous research sponsored by ACARP (Projects C3015 and C5063) and the development by CSIRO of accurate analytical procedures for trace elements in coal have been well received within Australia. Direct outcomes have included the production of a number of new Australian Standards. These include methods for arsenic, antimony, selenium and boron. There is still a requirement for a comprehensive set of procedures that can be used for the broad range of trace elements. The accurate determination of these trace elements is required as a consequence of environmental legislation worldwide. To date, many methods have been developed "in-house" and there is often a reluctance by laboratories to accept changes in established procedures.

An e-newsletter has also been published for this project, highlighting its significance for the industry.