This information is a summary of Deliverable B.3.1 Report on the laboratory testing of ceramic compositions with foundry byproducts.
The objective of this part of the project is to demonstrate at laboratory scale the valorization of iron foundry sands and dust in the ceramic tile production.
An initial assessment of the influence of the different byproducts in the firing behaviour of a porcelain tile body has been performed in order to evaluate for each by-product the need for the different pre-treatments of Action B2. The introduction of 5% of the green moulding byproducts does not modify firing temperature of the porcelain tile composition in a large extent. With green moulding sands the properties are very similar to the standard composition. The green moulding dusts, on the contrary reduce the bulk density of the specimens fired at optimum temperature due to the porosity generated during the decomposition of organic matter. The chromatic co-ordinates at optimum firing temperature for the compositions with the original green moulding byproducts show a small reduction of whiteness with respect to the standard composition. The different chemical moulding sands do not modify considerably firing behaviour as well as the dusts from furan binder (although with a slight decrease in bulk density). In the case of the other dusts (Phenol alkaline, Phenol Isocianate and Ester silicate), the density of the fired specimens is considerably lower in the whole interval tested and the bloating phenomena (typical of porcelain tiles) starts at lower temperatures with respect to the other compositions (STD and compositions with sands).
The magnetic separation performed can be considered as a valid pre-treatment as the whiteness of the compositions with the byproducts after this treatment is higher than for the original byproducts. Also, thermal treatments have also been proved as a valid pre-treatment as they reduce in a great extent organic matter.
Body compositions for the different types of ceramic tiles (red and white bodies) have been prepared with different mixtures of the foundry byproducts, replacing raw materials. These compositions have been characterized at laboratory scale evaluating their behaviour in the different stages of the manufacturing process and the properties of the fired specimens and the results have been acceptable.