Why is refining required when using a medium frequency induction heating furnace to smelt copper alloy, and how is refining performed?

When copper alloys are smelted in a medium frequency induction heating furnace, the molten copper often contains solid small particles, high melting point, and infusible oxide inclusions (Al2Osub>3, SiO>2, SnO2, etc.) dispersed in it. The decomposition pressure of these oxides It is very low and it is difficult to reduce it by oxidation method.

The main purpose of refining is to remove insoluble oxide inclusions in the copper alloy liquid. Since most of these oxide inclusions are acidic or neutral, alkaline fluxes are commonly used to remove these impurities. Commonly used alkaline refining fluxes include soda (Na2CO3), cryolite (Na3AIF6), fluorite (CaF2), calcium carbonate (CaCO3), borax (Na284O7), etc. These refining agents react with acidic oxides to form low melting point Double salt. These complex salts not only have low melting points and low density, they are easy to aggregate and float and enter the molten slag to be eliminated.

It should be pointed out that under normal circumstances, no flux is added when smelting copper alloys in a medium frequency induction heating furnace. Flux refining is only used when using miscellaneous copper with large amounts of impurities and some copper alloys with serious oxides, because after refining The amount of slag is large, so it must be thoroughly cleaned. Referring to the experience of molten steel spray metallurgy, using inert gas (N2, Ar, etc.) to spray and clean the molten copper is also a method of refining molten copper. Some people have already started researching it.