When using the fluxes for aluminum refining, the fluxes are pressed into the molten pool with a bell jar, and the volatile bubbles generated by the thermal decomposition of the flux or the chemical reaction with the metal are used to achieve the purpose of dehydrogenation.
The more gas produced by the same weight of aluminum refining fluxes, the better the degassing effect. At the same weight, the amount of gas produced by C2Cl6 is 1.5 times more than that of MnCl2, so the degassing effect is good. When refining with C2Cl6, it produces many bubbles, does not absorb moisture, has a small amount, and is cheap. It is a better solid degassing refining agent. However, ventilation and exhaust must be strengthened during use to avoid environmental pollution.
In industrial production, various non-toxic refining agents are also widely used. Most of them are mixed fluxes composed of oxidants such as sulfate or nitrate and elemental carbon to generate CO, CO2, and other bubbles in the melt.
In order to improve the refining effect and slow down the reaction strength, different proportions of hexachloroethane, cryolite powder, table salt and refractory bricks are also added. In addition to the refining effect, the non-toxic refining agent also has a certain metamorphic effect on the Al-Si alloy, but during refining, there are more smoke and dust, more slag, and greater metal loss.
When the charge is fully melted in the molten pool and the melt temperature reaches the melting temperature, a large amount of oxidized slag floating on the surface of the melt can be removed.
Before slagging, a layer of flux powder (slag cleaning agent) should be evenly sprinkled on the surface of the melt to make the oxidation slag and metal easy to separate, facilitate the slagging operation, and reduce the amount of metal carried out. The slag should be removed smoothly to prevent the slag from getting involved in the melt. Slag removal must be thorough, because the presence of scum will increase the gas content of the melt and may contaminate the metal.