aw materials represent the backbone of our economy and are a significant lever concerning global warming. As the energy-intensive primary raw material production has by far the highest impact on the product’s carbon footprint, supporting circular economy goals will contribute to saving primary raw materials and consequently to environmental protection. Due to the large diversity of refractories, the project mainly focuses on breakout material from the cement industry’s rotary kilns or the steel industry’s ladles. One of the first step of the project is the characterization of the breakout material to acquire a comprehensive database. It is necessary to enable a simultaneous sample investigation by all project partners. To do so, a representative sampling and subsequent sample distribution combined with a preliminary analysis of chemical and mineralogical composition are mandatory. The first representative sampling was performed on spent refractories of a cement rotary kiln. The chemical results were achieved by XRF analysis revealing that the bulk composition mainly consists of MgO and Al2O3 adding up to about >90 wt%. Additionally, Fe2O3, CaO and SiO2 could be measured summing up to <5 wt% in total. The application of refuse-derived fuels (RDF) in cement rotary kilns, led to the contamination of the spent refractories with Na, K or S. These elements contribute only a small amount to the bulk composition and are in the range of < 3 wt%. Regarding the mineralogical investigation achieved by XRD analysis, it can be stated that spent refractories mainly consist of Periclase (MgO), Spinel (MgAl2O4) and Sylvite (KCl); the latter is a product of infiltration and the reaction with reactive RDF. Regarding the evaluation of the sampling procedure, it can be stated that the position of sampling does not contribute significantly to either the chemical or the mineralogical variation, leading to the question of how to reduce the effort during sampling and still achieve high accuracy consistently.