Non-ferrous metal treatment

There are three main metal treatment (or refining) operations carried out in aluminium melting 

Modijication and grain rejining For aluminium alloys this usually involves the addition of small amounts of metal to the melt. These additions control the grain size and modify the microstructure of the solidifying metal and thus enhance the casting mechanical properties. Sodium or strontium are used for the modification, while grain refinement is achieved with titanium, titanium boride, zircon or carbon. This treatment is mostly performed in combination with degassing in a dedicated metal treatment station 

Fluxing This usually involves the addition of solid fluoride based fluxes to the melt, to remove solid contaminants. 

Grain modification Grain modifiers for magnesium alloy processes are usually in the form of zirconium or formerly hexachloroethane. The use of HCE for this purpose has been banned in the EU (Dir. 97/16/EC) 

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