Aluminum is a very active metal, which easily reacts with water vapor during the smelting process to generate hydrogen and oxide inclusions (Al2O3). These non-metallic inclusions are very harmful to the performance of aluminum products. Therefore, the purification of aluminum melt is one of the main ways to improve the quality of aluminum products. The flux method to remove inclusions and gases is a commonly used method for purifying aluminum melt, which has the advantages of simple process and low cost. Therefore, it is necessary to research and develop new degassing and impurity removal technologies.
The content of inclusions in industrial pure aluminum is generally above 0.1%, and most of the inclusions are larger than 10 microns in size. The international level of inclusion removal, the inclusion content in the aluminum melt is 0.02%, and the size of the inclusions is less than 7 microns. At present, the commonly used fluxes are fluorine salt and chlorine salt, etc. These salts are dried and ball milled and mixed, and then put into the aluminum melt. The molten salt is in contact with the aluminum melt, thereby eliminating a part of the inclusions, but this method cannot fully contact the flux and the aluminum melt. In addition, the mixed molten salt is pressed into a block and placed in the bottom of the aluminum melt. When the molten salt is melted, it floats from the bottom to the top layer, and the molten flux passes through the aluminum melt, so that a part of the inclusions can be removed. In addition, these salts are put into the aluminum melt, but some of the salts are not sufficiently mixed, these salts will not melt under the melting temperature of the aluminum melt, thereby forming new inclusions.
Aiming at the deficiencies of the above fluxes, AdTech proposes a method to filter and purify non-metallic inclusions in the aluminum melt, so that the granular flux is in full contact with the aluminum melt, and the flux and the non-metallic inclusions (Al2O3) in the aluminum melt are generated. Chemical reaction, so that the inclusions migrated into the flux will not return to the aluminum melt.
The method is specifically as follows: (1) The aluminum melt is filtered by the method of stirring the flux, and the aluminum melt is dispersed by the flux into fine aluminum droplets, so that the non-metallic inclusions in the aluminum melt can be distributed on the surface of the aluminum droplets. (2) The aluminum droplets redistribute the inclusions in the rotating flux, and the inclusions in the aluminum liquid have the opportunity to be distributed on the surface of the aluminum droplet to contact the flux. Flux for purifying the aluminum melt can remove the small inclusions in the aluminum melt to meet the requirements of large-scale industrial production of high-quality aluminum. Before casting, AdTech online degassing equipment and ceramic foam filter plates can be used to further purify the molten aluminum and provide the purity of the molten aluminum.