Because in the cell in the Friends of liquid aluminum many impurities, it must filtration before casting ingot.
It is reported that common methods include:
First, solvent purification method is to use a solvent added to the solution; the solvent has a low density, active, strong adsorption ability.
Second. Gas purification, commonly chlorine, nitrogen, chlorine or nitrogen mixed gas is a major aluminum purification method.
(1) Chlorine purification. Through the molten aluminum to generate a lot of fine bubbles of chlorine gas, sufficient mixing in the molten aluminum, the hydrogen dissolved therein, as well as some mechanical inclusions can be adsorbed on the small bubbles.
(2) Nitrogen purges method. Because of toxic chlorine gas, and high cost, so there has been purged with nitrogen. Use alumina balls (418mm) for the filter medium. N2 passed directly into the molten aluminum inside. Continuous purification of molten aluminum into the furnace through the filter layer of alumina balls, and by flushing with nitrogen, then liquid aluminum nonmetallic inclusions and hydrogen to remove dissolved, and then continuously discharged, so that a uniform distribution of fine nitrogen bubbles play a role in the purification of molten aluminum being treated.
(3) Mixed gas purification method. Using a mixture of chlorine gas and nitrogen gas to purify molten aluminum, its role is on the one hand and separating off hydrogen oxides, on the other hand remove some aluminum metal impurities (e.g. magnesium), commonly used in the composition is 90% nitrogen + 10% chlorine . There is also a 10% chlorine dioxide + 10% + 80% nitrogen. Thus better, make good diffusion of chlorine dioxide and nitrogen, the operating time can be shortened. Enterprises should be based on actual needs, select the appropriate cleaning methods.
