The certification of the gross calorific value and mass fractions of ash, C, H, N, S, Cl, major elements and trace elements in three coal materials: ERM®-EF411 (hard coal), ERM®-EF412 (brown coal) and ERM®-EF413 (furnace coke)

摘要

This report describes the production of ERM-EF411, ERM-EF412 and ERM-EF413, three coal materials certified for proximates and trace elements. The materials have been produced following ISO Guide 34:2009.Industial hard coal, brown coal and furnace coke were obtained, dried, milled (ERM-EF411 and ERM-EF413) and filled into aluminium laminated sachets.Between-unit homogeneity were quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. Within-unit heterogeneity was quantified to determine the minimum sample intake.The material was characterised by an intercomparison among laboratories of demonstrated competence and adhering to ISO/IEC 17025. Technically invalid results were removed but no outlier was eliminated on statistical grounds only. Uncertainties of the certified values were calculated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible heterogeneity and instability and to characterisation.The materials are intended for quality control and assessment of method performance. As any reference material, they can be used for control charts or validation studies, as well. The CRMs are available in sachets containing 50 g of dried material. The minimum amount of sample to be used, depending on the analyte, varies from 30 mg to 1 g. The CRM was accepted as European Reference Material (ERM®) after peer evaluation by the partners of the European Reference Materials consortium.