Fluxes are formulated from different blends of salts to clean molten aluminum of impurities and oxides. Fluxes can be applied by broadcasting it onto the molten bath and manually stirring through the aluminum bath with a scraper or skimmer. It can also be injected (the preferred way) deep into the melt. Either way, the flux grabs the impurities and floats them to the surface as dry dross ash. Skimmers or surface scrapers then remove the ash. Care should be taken to remove as little raw metallic as possible. Fluxes are formulated to specific alloys and holding temperatures.
Carpenter Brothers, Inc. supplies various injection and manual grade fluxes. Contact us for help in determining the best flux for your process.
Chemical fluxes for aluminum have a number of functions:
- Covering fluxes which form a molten layer to protect the melt from oxidation and hydrogen pick-up.
- Drossing-off fluxes coagulate the oxides allowing easy removal from the surface of the melt.
- Cleaning fluxes remove non-metallics from the melt by trapping the oxide particles as they float out.
- Fluxes modify the alloy, by introducing sodium, improving its microstructure.
- Exothermic fluxes ensure that aluminum liquid trapped in the dross layer is returned to the melt.
- Fluxes for reclaiming swarf, skimming, and turnings, giving a high metal yield.
- Fluxes for the removal of oxide build-up from furnace walls.