Why do we add salt when melting aluminum?
There are several main reasons for adding salt when melting aluminum:
I. Covering and protection
1. Preventing oxidation: Salt forms a covering layer on the surface of aluminum liquid, which can effectively block air and reduce the contact between aluminum liquid and oxygen in the air, thereby reducing the degree of oxidation of aluminum liquid and preventing the formation of aluminum oxide.
2. Reducing burnout: Reduce the loss of aluminum liquid caused by oxidation and improve the recovery rate of aluminum.
II. Refining effect 1. Adsorbing impurities: Salt can adsorb some impurities in aluminum liquid, such as oxides and hydrogen, which plays a role in refining aluminum liquid and improving the purity of aluminum.
2. Promoting impurity floating: Make impurities easier to gather and float to the surface of aluminum liquid, making it easier to remove.
When does aluminum begin to melt?
The melting point of aluminum is 660℃. When aluminum is heated to 660℃, it begins to melt. The actual melting situation is also affected by factors such as the heating environment and the purity of aluminum. If the heating rate is slow, it may start to melt at a temperature close to 660°C; if the purity is low or impurities are present, the melting point may change slightly, and the melting may start at a temperature slightly higher or lower than 660°C.