Measurement uncertainty of the mass fraction of total iron in iron ores, concentrates, agglomerates, and pellets

The paper considers the measurement of the mass fraction of total iron by the titrimetric method. A description of the measurement technique is given. It is shown that a special feature of the titrimetric method is the need to use a certified reference material with a known value of the mass fraction of total iron, which in this case acts as a reference measure with the value of which the corresponding value in the sample of the substance under consideration is compared. When implementing the measurement technique, two consistent input quantities are measured – the mass of the sample and the volume of the titrated solution; therefore, to determine both the titre and the mass fraction of total iron, the reduction method is used. In this case, it is necessary to separately evaluate the combined instrumental uncertainty of the measurements and the standard uncertainty of repeatability, based on which it is possible to calculate the standard and expanded uncertainty of the measurand. Procedures for the uncertainty evaluation of the titre and mass fraction of total iron measurements have been developed. Uncertainty budgets for these quantities have been evaluated. Examples of the uncertainty evaluation of the titre and mass fraction of total iron measurements based on real laboratory data and metrological characteristics of the measuring equipment used are considered.