Molten aluminium from the potlines is transported to the casthouse in crucibles by special tapping vehicles. Before entering the casthouse, the molten aluminium is treated in fluxing stations where sodium and impurities are removed. Fluxing is carried out in the crucibles by means of a special Hydro-patented process.
Using gas-fired furnaces
After the fluxing process, the molten aluminium is discharged from the crucibles into gas-fired mixing furnaces. Alloying elements and some solid aluminium metal are added to the melt in accordance with quality specifications.
The melt surface is skimmed to remove dross, or surface impurities, before casting. The molten metal is quality checked and thereafter transferred through a launder system and a Hydro-patented in-line filter refining unit for the effective removal of hydrogen and inclusions.
The molten metal is cast in the form of both foundry alloys and extrusion ingots. After the casting process, the ingots are automatically marked, stacked into bundles, weighed and packed for storage and shipment.
Extrusion ingot casting takes place in vertical, direct-chilled casting machines, consisting of water-cooled casting moulds of different sizes suitable for casting a large number of ingots, or logs, in the required lengths. The Hydro-patented casting process is used here.
After casting, the logs are heat-treated in homogenizing furnaces, sawn to the required length, marked, bundled, weighed and transferred to the storage area ready for shipment.