WP2 has been focused on developing methodologies to recycle scrap and scum. The scum it the term given to dross and sludge, which are impurities taken from the floating molten metal in the crucible and from the bottom of it (as seen in the figure above).
During WP2, the main results of the scrap recycling methodology development can be summarized as follows:
- A melting procedure has been developed, together with a recycling procedure. This recycling procedure impacts on composition results, and must therefore be fine tuned to the specific scraps and mixtures of scraps of each foundry.
- Composition analysis:
- Alloying elements have been found to be in line with the standards for input material and also for all mixes of scrap.
- The Fe and Ni impurity values are higher than the standard For Fe it’s caused by crucible contamination and for Ni it’s due to process contamination assumed in casting standards. Impurity values have to be monitored in industrial scale. These results have enabled the development of a protocol for taking action in situations of high values (metallurgical operations)
- The minimum process efficiency expected has been established to be
- AM60 > 76,5%
- AZ91 > 87,7%
Therefore the target of 80% established as KPI 7 has been achieved.
- A spreadsheet has been created in order to know how the different kinds of scrap could be introduced in the recycling furnace, taking into account the input material our the specific Remaghic foundry and the data provided by Grupo Antolin Ingenieria.
For the scum recycling process, the main conclusions could be summarized as follows:
- An innovative recycling technique for scum cleaning has been developed. For this purpose, fluxes had been employed that habitually are used for the refining of magnesium scrap, the protection of molten magnesium as well as for extinguishing of magnesium fire.
- A simulation study has been carried out in order to analyze the feasibility of two different stirring systems: mechanical stirring and electromagnetic stirring. After these studies it was concluded that the electromagnetic stirring is not a viable method for the scum recycling process. On the other hand, it has been shown that mechanical agitation is a great option to be integrated into the scum recycling process.
- The process efficiency is lower than the expected values; the amount of clean magnesium recovered in the process is lower than 45% in comparison with KPI target of 80%. But as these results can be interesting from an economic point of view, Grupo Antolin will assess this process feasibility in the exploitation analysis.
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