How to make such a variety of complex raw materials into qualified secondary aluminum ingots is the core issue of secondary aluminum production. The first step in the secondary aluminum production process is the classification process of scrap aluminum and miscellaneous aluminum.
The finer the classification and the more accurate the classification, the easier it is to control the chemical composition of recycled aluminum.
These substitutes are mainly non-aluminum parts made of steel or copper alloys. If it is not pulled out in time during the smelting process, the secondary aluminum slag will be completely added. (Such as iron, copper, etc.).
Therefore, in the early stage of secondary aluminum smelting, that is, when the scrap aluminum is just fused, there must be a process of separating the inserts (usually called the replacement process).
Secondary Aluminum Production
Pull out the insert from the scrap aluminum parts. The more timely and clean it is, the easier it is to control the chemical composition of the recycled aluminum.
When ironing, the temperature of the melt rises too high, because the temperature rise will cause the Fe and Cu elements in the insert to dissolve into the molten aluminum.
For various reasons, waste aluminum materials collected from various places are accumulated on the surface and become dirty, and some of them are severely rusted. These dirt and curved surfaces will enter the molten pool and form slag phase and oxide inclusions during the melting process, which will seriously damage the metallurgical quality of secondary aluminum.
Removal of these slag phases and oxide inclusions is also one of the important processes in the secondary aluminum smelting process.
Multi-stage purification is adopted, that is, rough purification is carried out first, the composition is adjusted, and the rare earth refinement is carried out again, and then inert gas is blown in to further enhance the purification effect and effectively remove the inclusions in the aluminum melt.