Environmental acceptance of foundry sands in earth construction requires reliable knowledge of sand composition and sand residue composition variations, especially regarding their environmental characteristics. This information together with an effective quality control system is also necessary for the promotion of sand residue utilization. The quality control system is foundry-specific. The influence of sand-binding agents and the causal connection between casting conditions and sand residue composition variations need to be studied at each foundry separately for the development of the quality control program. A specific quality control procedure based on detailed sand residue variation knowledge was developed as an example for a foundry using alkaline phenolic sand. Over 100 sand samples were collected from several points at the production line in order to estimate composition variations and to identify critical process parameters affecting the sand residue composition in the foundry. The sampling frequency and the number of quality control samples are dependent on the sand amounts produced at the foundry, the variations in critical properties, and the difference between the measured values and acceptable values. The specific quality control draft comprises a guideline for sampling strategy and the deviation management together with a proposal for necessary analytical testing methodology.
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