Copper casting deoxidation to make the metal in solution oxide reduction and remove the oxygen process is called deoxidation. Molten metals and alloys in the deoxidation process belongs to the replacement reaction.

Can dissolve in pure copper and copper alloys in the oxide only Cu2O, therefore, the deoxidation of copper alloy is to make the copper liquid copper oxide reduction process. That is, in the copper liquid to add a kind of affinity for oxygen than copper and oxygen affinity of the elements, the copper in the cuprous oxide to reduce out, generated by the deoxygenation product floats to the surface of the liquid to be excluded from the process known as deoxygenation. The substance added to the copper alloy liquid to reduce cuprous oxide is called deoxidiser.

Deoxidiser can be divided into surface deoxidiser and deoxidiser dissolved in metal.

Surface deoxidiser is basically insoluble in metal, the deoxidising effect is only carried out on the surface in contact with metal, and the deoxidising speed is slow. Its advantage is that because it is not dissolved in the metal, the deoxidiser will not affect the quality of the metal. Commonly used surface deoxidising agents are calcium carbide, magnesium boride, charcoal, boronic anhydride and so on.