DEVICE AND METHOD FOR RECOVERING A NON-FERROUS METAL FROM HOT DROSS

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 en 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 Noxygen 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.

Claims

1. Apparatus for recovery of non-ferrous metal from hot dross, preferably aluminium, alloys thereof, magnesium, zinc dross comprising a frame with dross compressing head, a sow mould for collection of drained metal from hot dross and a skim pan, provided with one or more through drainage holes in a bottom, put on a said sow mould, characterized in that provided with at least one through hole with connection for switching on vacuum through said skim pan bottom and/or sow mould, sealing located in the gap between said skim pan and saw mould.

2. The apparatus of claim 1, further comprising a seal between dross compressing head and skim pan.

3. The apparatus of claim 1 or 2, wherein comprising a cover with a sealing hermetically female the rod of hydraulic cylinder with a possibility of sliding along the rod and with a sealing hermetically to cover the skim pan.

4. The apparatus of claim 1 or 2, wherein comprising a cover with a sealing hermetically female the rod of hydraulic cylinder with a possibility of sliding along the rod and with a sealing hermetically to cover the skim pan by means of pneumatic or/and hydraulic cylinders (from 1 to 4 units), or/and electric drive.

5. The apparatus of claim 1 or 2, wherein comprising a cover with a sealing hermetically female the rod of hydraulic cylinder with a possibility of sliding along the rod and with a sealing hermetically to cover the skim pan by means of pneumatic or/and hydraulic cylinders (from 1 to 4 units), or/and electric drive and, at least one through hole in said cover provided a connection for inert gas supply.

6. The apparatus of claim 1 or 2, further comprising one or more vibrators of said skim pan and/or said head.

7. The apparatus of claim 1 or 2, further comprising one or more magneto-hydrodynamic (MEM) pumps for moving of metal to one or more drainage holes in the bottom of said skim pan.

8. The apparatus of claim 1 or 2, wherein said head is made hollow with at least two manifolds with air cooling.

9. The apparatus of claim 1 or 2, wherein the head is ribbed with one or more ribs.

10. The apparatus of claim 1 or 2, wherein the skim pan is ribbed with one or more ribs.

11. Method for recycling of non-ferrous metal from hot dross, preferably aluminium, alloys thereof, magnesium, zinc dross, comprising the following steps/operations: (a) hot dross skimming into the said apparatus skim pan p.1 or 2, (b) non-ferrous drained metal collection though at least one through hole in said skim pan bottom; (c) mechanically compression of dross by means of force application on said dross between a said head and a skim pan for recovery of non-ferrous metal from dross, metal migration effect to the compressed dross external surface, capsulating internal oxides core between said head and skim pan, drainage of non-ferrous metal portion through skim pan bottom hole/s and preventing oxygen access to dross; and, (d) switching on vacuum to a bottom part of skim pan and/or sow mould, provided with at least one through hole with a vacuum connection and a seal in a gap between skim pan and sow mould, wherein skim pan provided with one or more through holes in a bottom; and, simultaneously with (c) and (d), (e) collection of non-ferrous metal drained through hole in a skim pan bottom; (f) cooling of compressed dross and non-ferrous metal for solidification; to decrease a thermite reaction between non-ferrows metal and oxygen in dross by means of aforementioned dross compression, vacuum effect and metal cooling combination.

12. Method of claim 11, comprising additional thermal insulation or/and heating of a skim pan bottom with one or more drainage through holes, particularly by means of resistor or induction heater.

13. Method of claim 11 or 12, wherein vacuum depth in operation (d) is in a range 0.09 MPa to 0.1 k:Pa.

14. Method of claim 11 or 12, wherein vacuum depth in operation (d) is varied in proportional dependence on mechanical pressure force from said head.

15. Method of claim 11 or 12, wherein vacuum depth in operation (d) is varied in pulse form, particularly, sinusoidal, squared shape, triangle fmm or/and their combinations.

16. Method of claim 15, wherein vacuum pulses amplitude, shape, frequency and on-off time ratio are used for dross vibration achievement between said compressmg head and skim pan, including a frequency equal or closer to a mechanical resonance of dross between said compressing head and skim pan.

17 Method of claim 11 or 12, wherein in operation (c) series from 2 to 10sequential dross compressions are made.

18. Method of claim 11 or 12, including further mechanical breaking of compressed and cooled dross and separation for recycling of solidified non-ferrous metal.

19. Method of claim 11 or 12, including operation of free non-ferrous metal and oxides separation.

20. Method of claim 19, wherein a separation operation includes screening for free non-ferrous metal.

21. Method for recycling of non-ferrous metal from hot dross, preferably aluminium, alloys thereof, magnesium, zinc dross, comprising the following steps/ operations: (a) hot dross skimming into the said apparatus skim pan p. 1 or 2, (b) non-ferrous drained metal collection though at least one hole in said skim pan bottom; (c) mechanically compression of dross by means of force application on said dross between a said head and a skim pan for recovery of non-ferrous metal from dross, metal migration effect towards the compressed dross external surface, capsulating internal oxides core between said head and skim pan, drainage of non-ferrous metal portion through skim pan bottom hole/s and preventing oxygen access to metal in dross; and, (d) switching on vacuum to a bottom part of skim pan and/or sow mould, provided with at least one through hole with a vacuum connection, and a seal in a gap between said skim pan and said sow mold, wherein skim pan provided with one or more through drainage holes in a bottom; and, simultaneously with (c) and (d), (e) collection of non-ferrous metal drained through a hole in a skim pan bottom; (f) cooling of compressed dross and non-ferrous metal for solidification; (e) removal of compressed dross from skim pan; (g) removal of compressed dross from skim pan; (h) mechanical breaking of compressed dross for components separation, including salt or oxides parts of dross; (g) dross components separation; (h) melting of preferably metal containing part with coarse average diameter, dross residue metallic granulates for melted non-ferrows metal segregation from dross residue.

22. Method of claim 21, including operation of dross residue separation by means of dross salt-oxides parts collection;

23. Method of claim 21, including dross residue granules melting in sidewell furnace, including a pumping of granulates into the melt under the melt surface by means of MEM or mechanical pump vortex principle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The brief description of the invention is explained referring to the drawings below:

[0058] FIG. 1. General front side view of the apparatus for recovery of non-ferrous metal from hot dross provided with through hole in the skim pan bottom with connection for switching on vacuum “manually” just after the positioning of the skim pan inside of the said apparatus by means of a forklift.

[0059] FIG. 2. Back side view with a partial section of the apparatus for recovery of non-ferrous metal from hot dross provided with through hole in the skim pan bottom with connection for switching on vacuum, providing an automatic coupling of said skim pan with vacuum source (piping to vacuum pump) at the moment of positioning of the skim pan inside of the said apparatus by means of a forklift.

[0060] FIG. 3. General view with a partial section of the apparatus for recovery of non-ferrous metal from hot dross provided with an additional hermetic cover, hermetically female the rod of hydraulic cylinder with a possibility of sliding along the rod and hermetically to cover the skim pan by means of pneumatic or/and hydraulic cylinders (from 1 to 4 pcs), or/and electric drive.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0061] The apparatus comprises the head 1 with rod 2 for compression of hot dross, skimmed from melt surface in furnace/mixer and loaded into skim pan 3, provided with sealing 4 between head 1 and skim pan 3. Skim pan 3 provided with one or more through holes 5 in bottom for drainage of drained metal into lower saw mould 6. Drained metal is collected in the saw mould 6. There are sealing 8 between skim pan 3 and saw mould 6, and at least one through hole 9 with a connection for switching on vacuum through said skim pan bottom 3. There is a frame 7 with a dross compressing head 1 provided with a power drive 11, particularly, hydraulic cylinder with a rod 2.

The head 1 either does not have or has ribbing 12. Skim pan 3 either does not have or has ribbing 13. The dross compressing head 1 could be made hollow with at least two manifolds 14 with air cooling.

[0062] One or more vibrators of said skim pan and/or said head, further comprising one or more magneto-hydrodynamic (MHD) pumps 15 [FIG. 2] facilitate for moving of metal to one or more drainage holes 5 in the bottom of said skim pan 3.

[0063] In the case of low metal content in dross, below 50%, metallization and compressing of external surfaces of dross can be inefficient. In such case additional sealing 4 is applied between the dross compressing head 1 and skim pan 3.

[0064] Particularly, in case of additional sealing necessity, the apparatus can comprise additional hermetic cover 10 [FIG. 2-3], hermetically female the rod 2 of hydraulic cylinder 11 with a possibility of sliding along the rod 2 and hermetically to cover the skim pan 3.

[0065] With a purpose to reduce the additional cover movement time, the apparatus can comprise additional hermetic cover 10, hermetically female the rod 2 of hydraulic cylinder 11 with a possibility of sliding along the rod 2 and hermetically to cover the skim pan 3 by means of pneumatic or/and hydraulic cylinders 17 (from 1 to 4 pcs), or/and electric drive [FIGS. 2-3].

[0066] With a purpose of additional insulation from the air oxygen and pressure increase from the head side, the apparatus can comprise additional hermetic cover 10, hermetically female the rod 2 of hydraulic cylinder 11 with a possibility of sliding along the rod 2 and hermetically to cover the skim pan 3 by means of pneumatic or/and hydraulic cylinders 17 (from 1 to 4 pcs), or/and electric drive and, at least one or more through hole 16 in said cover providing a connection for inert gas supply.

[0067] The apparatus operation is as following: The skimpan 3 is put on the saw mould 6 by means of forklift. Hot dross is to be skimmed from the melting/holding furnace melt surface into the skim pan 3 which is put on the saw mould 6. The set of said skim pan 3 put on the saw mould 6 is to be placed by means of forklift into the apparatus for hot dross compression (press), provided the said seal 8 is located between said skim pan 3 and saw mould 6 and with one or more through holes 9 with connection for switching on vacuum through said skim pan 3 bottom. The head 1 with rod 2 compress the hot dross, and the head 1 can be made hollow with at least two manifolds 14 to be cooled with air.

[0068] The sealing 4 between said head 1 and skim pan 3 promote a vacuumization.

[0069] In case of additional sealing necessity, the apparatus can comprise additional hermetic cover 10 [FIGS. 2-3], hermetically female the rod 2 of hydraulic cylinder 11 with a possibility of sliding along the rod 2 and hermetically to cover the skim pan 3.

[0070] With a purpose to reduce the additional cover 10 movement time, the apparatus can comprise additional hermetic cover 10, hermetically female the rod 2 of hydraulic cylinder 11 with a possibility of sliding along the rod 2 and hermetically to cover the skim pan 3 by means of pneumatic or/and hydraulic cylinders 17 (from 1 to 4 pcs) [FIGS. 3-5], or/and electric drive [FIGS. 2-3],.

[0071] The drained metal is to be collected in the said saw mould 6.

[0072] In comparison with the prototype, other conditions being equal, vacuum and/or vibrator of head and/or skim pan, and/or MHD pumps facilitate increase in metal recovery from dross.

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