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Thermodynamic modelling |
| Thermodynamic modelling is a powerful tool to predict chemical reactions at high temperatures. At the Ceramics Research Centre we use thermodynamic software packages within a variety of research areas, such as e.g. slag - refractory interactions or inclusion chemistry of steels. Although commercial thermodynamic packages provide databases to model high-temperature chemistry, sometimes fine-tuning of such models is required to account for all circumstances in our plant processes. At the CRC we routinely use results from high-temperature experiments to optimize thermodynamic databases. Such an approach ensures the best possible thermodynamic simulations and can therefore contribute significantly to industrial process optimization.
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| For example, on basis of the chemical composition of a metallurgical slag it is possible to predict whether it will dissolve the refractory material. The thermodynamic calculation will predict what solid phase at operating temperature will appear/crystallize in the (liquid) slag phase. In case this phase is identical to the refractory material the refractory will be stable (See left figure in which at operating temperature (say 1600°C) the “green” MgO phase appears to be the stable solid phase with the “”blue”slag phase). Therefore, MgO is a suitable refractory material for this application. In the right figure we have an altered slag composition that has a stable combination with the “purple” silicate phase. This will result in continuous dissolution of MgO refractory in the slag. Another example, generated in a similar way is the prediction of the appearance of a so-called lime phase in cooled slag. In case this happens such a slag is less suitable for re-use as road filler. The lime phase will cause unwanted swelling behaviour. Obviously, the slag produced under conditions depicted in the left figure generates the “red” lime phase and consequently is not preferred. These kinds of thermodynamic predictive calculations can be directly coupled to the process/control software to safeguard the refractories in use or the quality of the product.
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