APPROACH FOR HOMOGENEITY ASSESSMENT OF GEOLOGICAL REFERENCE MATERIALS

• DOI: 10.22533/at.ed.3173282323084

• Palavras-chave: geological reference material, material processing, assessment of homogeneity, experimental homogeneity study.

• Keywords: geological reference material, material processing, assessment of homogeneity, experimental homogeneity study.

• Abstract:

  Materials of mineral origin are typically heterogeneous in composition. The material processing for the production of ore and mineral reference materials – RM at CETEM is described. The raw material was submitted to a several processing stages to ensure that individual RM unit meets the requirements for homogeneity and stability for its intended use. After material processing, an experimental homogeneity study was carried out in a subset of twenty RM units, selected from each RM batch, measured by an appropriate measurement procedure, in triplicate, under repeatability conditions, according to a randomized completed block design. This approach aimed to compare the dispersion of results for different RM units with the dispersion under repeatability conditions and determine the between-unit variance, which could then be used to calculate the uncertainty associated with heterogeneity. The evaluation of the experimental homogeneity data for the bauxite certified reference material BXBA-4 is given as an example.