METHOD FOR OBTAINING METALS AND RARE EARTH METALS FROM SCRAP

• US 20140090518A1
• Filed: 05/03/2012
• Published: 04/03/2014
• Est. Priority Date: 05/10/2011
• Status: Active Grant

• Current Assignee: Ecoloop GmbH
• Original Assignee: Ecoloop GmbH
• Inventors: Stumpf, Thomas, Baumann, Leonhard, Mller, Roland
• Granted Patent: US 9,322,077 B2
• Time in Patent Office: Days
• US Class Current: 75/631
• CPC Class Codes: C10J 2300/0906 Physical processes, e.g. shredding, comminuting, chopping, sorting
• CPC Class Codes: C10J 2300/0946 Waste, e.g. MSW, tires, glass, tar sand, peat, paper, lignite, oil shale
• CPC Class Codes: C10J 2300/0996 Calcium-containing inorganic materials, e.g. lime
• CPC Class Codes: C10J 3/20 Apparatus; Plants
• CPC Class Codes: C10K 1/007 of metal compounds
• CPC Class Codes: C10K 1/024 by filtration
• CPC Class Codes: C22B 11/025 from manufactured products, e.g. from printed circuit boards, from photographic films, paper, or baths
• CPC Class Codes: C22B 5/00 General methods of reducing to metals
• CPC Class Codes: C22B 5/10 by solid carbonaceous reducing agents
• CPC Class Codes: C22B 5/12 by gases
• CPC Class Codes: C22B 5/14 fluidised material
• CPC Class Codes: C22B 59/00 Obtaining rare earth metals
• CPC Class Codes: C22B 7/001 Dry processes
• CPC Class Codes: C22B 7/02 Working-up flue dust
• CPC Class Codes: Y02P 10/20 Recycling

Abstract

The method is used to obtain metals, noble metals, and rare earth metals from scrap. The aim of the invention is to provide a method that allows an efficient recovery even from electronic scrap. This is achieved in that the scrap and carbon-containing materials (A) are oxidized with oxygen containing gases (11) in the presence of alkaline materials under overall reducing conditions with an overall lambda of <1 in an updraft gasifier (2) with a bulk material moving bed, said gasifier having a reduction zone (13) and an oxidation zone (7). The resulting syngas is drawn at the upper part (16) of the updraft gasifier, and the metals, noble metals, and rare earth metals are bound at least partly to the alkaline materials as oxides and/or in elementary form. Finally, said metals are obtained from the process as an enriched mixture (B) by means of physical separation methods.

Claims

1. A method for obtaining metals, noble metals and rare earth metals from scrap, characterized in that in a countercurrent gasifier having a moving bulk-material bed, which has a reduction zone and an oxidation zone, the scrap and carbon-containing materials are oxidized with oxygen-containing gases in the presence of alkaline substances under overall reductive conditions at a total lambda of less than 1;

the resultant synthesis gas is drawn off at the top part of the countercurrent gasifier, and the metals, noble metals and rare earth metals are at least partially bound as oxides and/or in elemental form to the alkaline substances, whereupon they are obtained from the process as an enriched mixture by physical separation methods.

2. The method of claim 1, characterized in that the carbon-containing material and the scrap are electronic scrap and/or entire outdated electronic devices.

3. The method of claim 1, characterized in that cable residues and/or other metal-containing dusts or solids are added to the carbon-containing material and scrap, in order to further increase the proportion of usable metal in the bulk material.

4. The method of claim 3, characterized in that the metal-containing dusts or solids are ashes from combustion processes, or oil shale or other naturally occurring carbon-containing substances that contain metal.

5. The method of claim 1, characterized in that as the alkaline substances, metal oxides, metal carbonates and metal hydroxides or mixtures of two or three of these substances are used, and they are metered purposefully into the countercurrent gasifier and/or into the gas phase above the reduction zone, and/or admixed with the carbon-containing materials before entry into the vertical processing chamber.

6. The method of claim 3, characterized in that the metal oxides, metal carbonates and metal hydroxides contain elements of the alkali metals or elements of the alkaline earth metals and especially preferably calcium as a cation.

7. The method of claim 1, characterized in that the alkaline substances are used at least partially in fine-granular form with a particle size of less than 2 mm as a solid and/or as a suspension in water.

8. The method of claim 1, characterized in that the moving bulk-material bed is formed partially by additional metering of coarse material in order to increase the flowability of the bulk material and/or its gas permeability, and the coarse material is admixed with the carbon-containing materials before entry into the vertical processing chamber.

9. The method of claim 6, characterized in that as the coarse material, mineral substances and/or other inorganic substances or mixtures of substances having a particle size of 2 mm to 300 mm are used.

10. The method of claim 6, characterized in that as the coarse material, wood and/or other biogenic materials having a particle size of 2 mm to 300 mm are used.

11. The method of claim 1, characterized in that the overall reductive conditions proceed at a total lambda of less than 0.7 over all the stages of the processing chamber, and preferably 0.5 or less.

12. The method of claim 1, characterized in that before entry into the vertical processing chamber, additional carbon carriers are admixed with the carbon-containing materials, to increase the concentration of usable carbon-containing components in the moving bulk-material bed.

13. The method of claim 1, characterized in that the temperature in the reduction zone is up to 1500°

C., so that the metals and rare earth metals, which are present in the form of oxides and as elements have a standard potential in an acid solution of less than 0 volts compared to the standard hydrogen electrode, are reduced at least partially into elemental metals by means of the carbon that is present and the carbon monoxide that is contained in the synthesis gas.

14. The method of claim 1, characterized in that the reduced metals and rare earth metals as well as the metals, noble metals or rare earth metals already present at the outset as elements in the carbon-containing materials at least partially reach their melting point in the reduction zone and are at least partially fixed as molten droplets on the moving bulk-material bed and are transported onward in the countercurrent gasifier into the oxidation zone.

15. The method of claim 1, characterized in that the metals reduced in the reduction zone and the metals, noble metals or rare earth metals already present in elemental form at the outset of the process, if they have normal potentials in an acid solution of less than 1 volt compared to the standard hydrogen electrode, are converted at least partially into oxides in the oxidation zone at temperatures of up to 1800°

C. and at a lambda of greater than 1, which are enriched in the proportion of fine-granular mineral substances, and as a result a mixture of fine-granular alkaline substances, for the most part metals and rare earth metals in oxide form, and noble metals in elemental form, is generated.

16. The method of claim 1, characterized in that the mixture comprising fine-granular alkaline substances, metals and rare earth metals in oxide form, and noble metals in elemental form is partially discharged with the moving bulk-material bed at the lower end of the countercurrent gasifier and partly discharged via the synthesis gas from the upper end of the countercurrent gasifier.

17. The method of claim 14, characterized in that the mixture comprising fine-granular mineral substances, metals and rare earth metals in oxide form, and noble metals in elemental form which is discharged at the lower end of the countercurrent gasifier together with the moving bulk-material bed is separated, as a mixture of fine material from the coarse-particulate bulk material, by screening.

18. The method of claim 14, characterized in that the mixture comprising fine-granular mineral substances, metals and rare earth metals in oxide form, and noble metals in elemental form which is discharged via the synthesis gas at the upper end of the countercurrent gasifier is carried together with the synthesis gas via a physical solids separator and separated out as filter dust.

19. The method of claim 15, characterized in that the fine material mixture and/or the filter dust is partially returned to the moving bulk-material bed at, and as a result of this partial recirculation, a further enrichment of the metals and rare earth metals in oxide form and noble metals in elemental form is achieved.

20. The method of claim 1, characterized in that all the carbon-containing materials introduced into the process and the carbon carriers purposefully metered in are adjusted in their total metered quantity in the moving bulk-material bed such that sufficient carbon for the reduction reactions in the reduction zone as well as sufficiently oxidizable carbon in the oxidation zone for the energy input into the countercurrent gasifier are available.

21. The method of claim 1, characterized in that all the oxygen-containing gases introduced into the process are adjusted in their total metered quantity such that sufficient oxygen for complete oxidation of the pyrolysis coke residues present in the oxidation zone and as applicable, residues of further carbon carriers and oxidizable metals, rare earth metals and noble metals in elemental form, are available.

22. The method of claim 1, characterized in that in the vertical processing chamber and/or in the gas phase of the gaseous reaction products drawn off, in the presence of water vapor and calcium oxide and/or calcium carbonate and/or calcium hydroxide, a calcium-catalyzed reformation of substantial proportions of the resultant of the oil- and/or tar-containing cleavage products, which have a chain length of greater than C4, into carbon monoxide, carbon dioxide and hydrogen is performed at temperatures of more than 400°

.

23. The method of claim 5, characterized in that the water vapor is purposefully metered into the vertical processing chamber and/or into the gas phase above the reduction zone, and/or is furnished in situ from the residual moisture of the materials used.