Alcan has developed a compact, modular degassing system, commercialised by STAS, which uses spinning nozzles in the molten aluminium directly in the casting trough prior to filtering and casting. No heating is required nor is there any loss of metal due to flushing when changing alloys.

 

The DBF, designed and commercialised by STAS, placed between the furnace and the casting operation, consists of an insulated box containing layers of carefully sized alumina balls through which molten aluminium flows from top to bottom. They are available in sizes ranging from 50 to 1,500 kg/min flow rates. Up to 5,000 tonnes per filter medium can be expected, depending on the alloy and alloy changes.

 

STAS has developed and commercialised a hot crucible cleaner, which can clean rapidly with an optimum cutting action not only hot but cold crucibles in a few minutes. Due to the automatic action of the cleaner, there are considerable savings with operators no longer required. Both single and dual head machines are available for different crucibles.

 

Drosses oxidise readily above 400°C, causing a loss of valuable aluminium metal. The dross needs to be cooled as rapidly as possible, safely and cheaply. Air cooling means losing valuable aluminium metal. Other mechanical methods use moving parts which are expensive to maintain and unreliable and cannot cool all types of drosses under all conditions.

 

STAS has developed and commercialised a semi-automatic pneumatic reamer, which can be installed in a potroom or adjacent building. It cleans rapidly within a few minutes either straight or curved tubes. Due to the extremely rapid cleaning action, tubes can now be cleaned before every siphoning operation, thus extending the life of the tubes considerably.

 

STAS has developed rotary flux/gas injectors which use either salts or a reduced amount of chlorine gas, together with nitrogen as a carrier gas. Flux is non-hazardous to the environment and reducing chlorine gas is desirable.

 

The TAC, designed and commercialised by STAS, successfully reduces Na and Li contents to specification levels in less than 8 minutes without the use of chlorine. TAC achieves these objectives by injecting AlF3 directly into the molten metal in the pot room crucible.

 

Automate the manual skimming in order to a) reduce labour costs together with safety and hygiene problems; and b) skim more efficiently by removing nearly 100% of material.