DIN EN ISO 16968:2015-09

This International Standard is intended for the determination of the minor elements arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, molybdenum, nickel, lead, antimony, vanadium, and zinc in all solid biofuels. Further, it describes methods for sample decomposition and suggests suitable instrumental methods for the determination of the elements of interest in the digests. The determination of other elements such as selenium, tin, and thallium is also possible with the method described in this International Standard. The minor elements present in solid biofuels can, in some cases, be of environmental concern, for example it has been shown that certain energy crops will concentrate cadmium and, in polluted areas, other toxic elements may be found at elevated concentrations in the biofuels. This can be a problem if, for example, the ash from the combustion is to be put back in the forest as a fertilizer. Trace elements in biofuels are often present at very low concentrations requiring great care to avoid contamination in the sample preparation and decomposition steps. The typical concentrations of minor elements in solid biofuels can be found in ISO 17225-1. In this International Standard, wet chemical methods are described. Alternative methods such as X-ray fluorescence (XRF) or direct mercury analysers may be used when validated with suitable materials (biomass reference materials). This document has been prepared by Technical Committee ISO/TC 238 "Solid biofuels" in collaboration with Technical Committee CEN/TC 335 "Solid biofuels", the secretariat of which is held by SIS (Sweden).