Patent WO-2016003321-A2 (WO)
Title: Device and method for recovering a non-ferrous metal from hot dross
Inventor: POPOV YURY NIKOLAEVICH
IPC: C22B7/04
Filed: 2015-06-24
Abstract: This invention relates to the field of recycling non-ferrous metals (for example, aluminium and alloys thereof, magnesium and zinc). The claimed device comprises: a frame with a dross compression head; an ingot mold for collecting metal compressed from the dross; a dross pot mounted on said ingot mold; at least one through opening with a connection means for supplying a vacuum, said opening being situated in the bottom part of the dross pot and/or in the ingot mold; and a seal, situated in the gap between the dross pot and the ingot mold; furthermore, one or several through drainage openings are provided in the bottom part of the dross pot. The device may comprise a seal between the dross compression head and the dross pot. The head may be provided with one or several ribs. The dross pot may be provided with one or several ribs. The head may be hollow and provided with two or more air-cooling connecting pipes. The device may comprise a cover, sealingly mounted on a rod of a hydraulic cylinder of a device for compressing hot dross such as to be capable of sliding along the rod, said cover sealingly conforming to the edges of the dross pot. The device may comprise a cover, sealingly mounted on a rod of a hydraulic cylinder of a dross press such as to be capable of sliding along the rod with the aid of pneumatic or hydraulic cylinders (1 to 4 in total), said cover sealingly conforming to the edges of the dross pot. The device may comprise a cover, sealingly mounted on a rod of a hydraulic cylinder of a dross press such as to be capable of sliding along the rod, said cover sealingly conforming to the edges of the dross pot, and at least one through opening with a connection means for supplying an inert gas. The device may comprise one or several dross pot vibrators and/or head vibrators, or magnetohydrodynamic (MHD) pumps, for moving the metal toward the one or several drainage openings in the bottom part of the dross pot. The claimed method for recovering a non-ferrous metal from hot dross, preferably aluminium, aluminium alloy, magnesium or zinc dross, comprises the following steps/operations: (a) removing dross to the dross pot of the above-mentioned device; (b) collecting a non-ferrous metal, which is drained through at least one through opening in the bottom part of the dross pot; (c) mechanically compressing the dross by the application of force to the dross between a compression head and the dross pot in order to recover a non-ferrous metal from the dross, enable the migration of the non-ferrous metal in the direction of the surface boundary of the compressed dross, the formation of an outer layer of non-ferrous metal, which encapsulates an inner oxide core of dross between the aforementioned compression head and the dross pot, and the drainage of a portion of the non-ferrous metal through a through opening(s) in the bottom part of the dross pot, and to prevent oxygen from penetrating the non-ferrous metal in the dross; and (d) supplying a vacuum to the bottom part of the dross pot and/or to the ingot mold, which comprises at least one through opening with a connection means for supplying a vacuum, and a seal, situated in the gap between the dross pot and the ingot mold, the dross pot being provided with one or several through drainage openings in the bottom part thereof; and, simultaneously with (c) and (d), (e) collecting the non-ferrous metal drained through the through opening in the bottom part of the dross pot; and (f) cooling the compressed dross and the non-ferrous metal in order to harden the non-ferrous metal, thus reducing the thermite reaction of the non-ferrous metal and oxygen in the dross by combining the above-mentioned compression of the dross with the effect of a vacuum and the cooling of the metal. The invention increases the recovery of a non-ferrous metal from dross.