The production requirements of flux for aluminum foundry meet the strict general quality requirements of raw materials (commercial purity, uniform size, moisture content less than 1%), and are used in the manufacturing process. The control of these variables ensures consistent products and consistent performance.
For the history of most aluminum foundries, powdered fluxes have been used. Powder flux for aluminum foundry has been used commercially for nearly 60 years. Due to concerns about environmental emissions, research and development of possible new formulations and variations of traditional mixtures have more closely evaluated the use of fluoride.
According to reports, if the fluoride is removed from the formulation, it will result in a helpless and inefficient flux. At the same time, it is reported that only when the form of the flux changes from powder to particles, the emission of fluorine-containing flux can be reduced by at least half. It is still necessary to be cautious to mention that the discharge of powder flux is within the standard environmental limits.
Fluorinated salts are subject to stricter environmental regulations and constraints. Therefore, fluorine-free flux can be obtained. However, it is important to realize that fluorine-free fluxes will never be as effective as fluorine-containing fluxes. On the other hand, fluorine-free flux is the best choice to eliminate smoke and odors inside the factory, and can process metals in a resistance furnace without damaging electrical components.
The granular flux may or may not have the same formula as the powder flux. However, due to the different crystal grain morphology, granular flux has other operational and product advantages over powder flux. Particle fluxes are less polluting to the atmosphere; emissions are reduced by at least 50%.
The granular flux for aluminum foundry greatly reduces the odor and smoke, which is conducive to working closer to the furnace in the slag removal operation. The granular flux is relatively small and dust-free, so it is easier to apply and spread on the molten surface.