A METHOD AND DEVICE FOR PRODUCING ALUMINUM, AS WELL AS A METHOD AND DEVICE FOR PRODUCING RAW MATERIALS CONTAINING ALUMINUM CHLORIDE

Claims

1. A method for the electrolytic production of aluminum from aluminum chloride in a block (9) of an electrolytic cell containing an electrolyte, as well as at least one anode (17) and at least one cathode (18), wherein the method includes the following stages: (a) chlorinating the aluminum-containing feedstock using gaseous chlorine and a carbonaceous reducing agent, CO and / or phosgene, to form a product gas stream (14) containing gaseous aluminum chloride and gaseous CO2; (b) passing all or part of the product gas stream (14) containing gaseous aluminium chloride and gaseous CO2 coming from the chlorination step (a) to an absorption unit (5, 35, 75) containing a molten salt liquid (6) in which gaseous aluminium chloride is at least partially absorbed, forming a molten salt liquid enriched in aluminium chloride, wherein gaseous CO2(12) and any other gaseous components that have not been absorbed by the molten salt liquid are withdrawn from the absorption unit (5) and, optionally, processed in one or more separate processing unit(s); (c) transferring, either directly or indirectly, a portion of the molten salt liquid enriched with aluminum chloride from the absorption unit into an electrolyte contained in an electrolytic cell unit in which the aluminum chloride is electrolytically converted into metallic aluminum and gaseous chlorine; and (d) transferring, either directly or indirectly, a portion of the aluminum chloride-depleted electrolyte, which has a lower concentration of aluminum chloride than the molten salt liquid, from the electrolytic cell unit to the absorption unit, thereby replacing some of the molten salt liquid removed from the absorption unit.

2. The method according to claim 1, wherein the aluminum-containing raw material is a raw material containing aluminum oxide.

3. The method according to claim 2, wherein the raw material containing aluminum oxide is one or more types of raw material selected from the group consisting of aluminum oxide (Al2O3), aluminum oxide ore or aluminum oxide clay mineral.

4. The method according to any one of claims 1 to 3, wherein the carbon-containing reducing agent is selected from carbon, gaseous CO, gaseous CH4, gaseous CCl4 and COCl2.

5. The method according to any one of claims 1 to 4, wherein the molten salt liquid located in the absorption unit is a mixture of molten salts containing aluminum chloride and one or more salt(s) selected from the group consisting of an alkali metal chloride and an alkaline earth metal chloride.

6. The method according to claim 5, wherein the alkali metal chloride is one or more salts selected from LiCl, NaCl and KCl, and the alkaline earth metal chloride is one or more salts selected from MgCl2 and CaCl2.

7. The method according to any one of paragraphs 5, 6, in which the concentration of aluminum chloride in the molten salt liquid located in the absorption unit is from 45 to 90% by weight.

8. The method according to any one of claims 1 to 7, wherein the electrolyte located in the electrolytic cell unit is a mixture of molten salts containing aluminum chloride and one or more salts (salt) selected from the group consisting of an alkali metal chloride and an alkaline earth metal chloride; wherein said one or more salts (salt) selected from the group consisting of an alkali metal chloride and an alkaline earth metal chloride is the same as in the molten salt liquid located in the absorption unit.

9. The method according to claim 8, wherein the ratio between the salts in the composition of the electrolyte, with the exception of aluminum chloride, is within 2 percent by weight of the ratio between the salts in the composition of the molten salt liquid located in the absorption unit, with the exception of aluminum chloride.

10. The method according to any one of paragraphs. 8, 9, in which the electrolyte located in the electrolytic cell block contains 0.1-50% by weight of aluminum chloride; or 0.5-20% by weight of aluminum chloride; or 1-10% by weight of aluminum chloride; or 2-5% by weight of aluminum chloride.

11. The method according to any one of paragraphs 1-10, in which the concentration of aluminum chloride in the molten salt liquid located in the absorption unit is higher than the concentration of aluminum chloride in the electrolyte located in the electrolytic cell block.

12. The method according to any one of paragraphs. 1-11, in which a portion of the molten salt liquid enriched with aluminum chloride is moved indirectly from the absorption unit to the electrolytic cell unit through one or more intermediate volume(s).

13. The method according to claim 12, wherein at least partial solidification of the molten salt liquid enriched with aluminum chloride occurs in one or more intermediate volume(s).

14. The method according to claim 12 or 13, in which in one or more intermediate volume(s) a portion of the molten salt liquid enriched in aluminum chloride is mixed with a portion of the electrolyte depleted in aluminum chloride.

15. The method according to any one of paragraphs. 1-11, in which a portion of the molten salt liquid enriched with aluminum chloride is moved directly from the absorption unit to the electrolytic cell unit through one or more fluidly communicating channel(s), optionally through one or more intermediate mixing volume(s).

16. The method according to any one of paragraphs 1-15, in which the electrolyte depleted in aluminum chloride is moved indirectly from the electrolytic cell unit to the absorption unit through one or more intermediate volume(s).

17. The method according to claim 16, wherein at least partial solidification of the electrolyte depleted in aluminum chloride occurs in one or more intermediate volume(s).

18. The method according to any one of paragraphs 16, 17, in which in one or more intermediate volumes (volumes) a portion of the electrolyte depleted in aluminum chloride is mixed with a portion of the molten salt liquid enriched in aluminum chloride.

19. The method according to any one of claims 1 to 15, in which a portion of the electrolyte depleted in aluminum chloride is moved directly from the electrolytic cell unit to the absorption unit through one or more fluidly communicating channel(s), optionally through one or more intermediate mixing volume(s).

20. The method according to any one of claims 1 to 19, wherein the temperature in the absorption unit is below 400°C, or below 300°C, or below 200°C.

21. The method according to any one of claims 1-20, wherein the gaseous medium in the absorption unit contains a chlorinating reagent.

22. The method according to claim 21, wherein the chlorinating reagent is selected from the group consisting of a mixture of gaseous chlorine and gaseous carbon monoxide (CO), gaseous phosgene (COCl2), gaseous carbon tetrachloride (CCl4), gaseous methane (CH4) and / or carbon and gaseous chlorine.

23. The method according to any one of claims 1 to 22, further comprising collecting and passing gaseous CO2 exiting the chlorination step (a) and / or the absorption step (b) into a reactor, and converting the CO2 into gaseous CO and O2.

24. The method according to claim 23, comprising feeding gaseous CO to the chlorination stage (a).

25. The method according to any one of claims 1 to 24, further comprising collecting gaseous Cl2 coming from the electrolytic cell unit (9) and passing the gaseous Cl2 to the chlorination step (a).

26. A device for implementing the method according to any one of paragraphs 1-25, comprising: a chlorination reactor vessel (1) comprising a feed channel for an aluminium-containing raw material (2), a feed channel for a chlorinating gas (4) and a feed channel for a reducing agent (3), as well as an outlet for a product gas stream containing at least gaseous aluminium chloride and gaseous CO2; an absorption unit (5, 35, 75) comprising an inlet (22, 32, 72) for receiving all or part of the product gas stream (14) coming from the chlorination reactor vessel (1), wherein the absorption unit (5, 35, 75) contains a molten salt liquid in which gaseous components of the product gas stream are partially absorbed, forming a molten salt liquid enriched in aluminum chloride, and comprising a gas outlet (12, 33, 73) for extracting gaseous CO2 and any gases not absorbed by the molten salt liquid in the absorption unit; and one or more transfer means (7, 107, 8, 108) located between said absorption unit (5, 35, 75) and electrolytic cell unit (9), configured to directly or indirectly transfer molten salt liquid enriched with aluminum chloride from the absorption unit (5) to the electrolytic cell unit (9), in which said aluminum chloride is converted electrolytically into metallic aluminum (24) and gaseous chlorine, and also configured to directly or indirectly transfer electrolyte depleted in aluminum chloride from the electrolytic cell unit (9) to the absorption unit (5, 35, 75).

27. The device according to claim 26, in which the absorption unit (5) is a bubble column or vessel containing means for distributing the gaseous product stream in the molten salt liquid.

28. The device according to claim 26, in which the absorption unit is a counter-current absorption unit (35) comprising at least an inlet (36) for an electrolyte depleted in aluminum chloride coming from the electrolytic cell unit (9) and an outlet (34) for a molten salt liquid enriched in aluminum chloride; means (30) configured to circulate the molten salt liquid (6) in the counter-current absorption unit (35); an inlet (32) for a product gas stream (14) and an outlet (33) for extracting gaseous CO2 and any gases not absorbed by the molten salt liquid, wherein the direction (37) of flow of the product gas stream (14) is formed opposite to the direction of flow of the molten salt liquid (31).

29. The apparatus of claim 26, wherein the absorption unit is a tray absorption tower (75) having a plurality of absorption plates (76) arranged vertically and at a distance from each other in the absorption tower, comprising an inlet (72) for a product gas stream located below a lower plate, and an inlet for an electrolyte depleted in aluminum chloride located above an upper plate, and furthermore an outlet (73) located at the top of the absorption tower for extracting gaseous CO2 and any other gases not absorbed by the molten salt liquid (6), and an outlet (74) for molten salt liquid (78) enriched in aluminum chloride at the bottom of the absorption tower.

30. The device according to any one of paragraphs. 26-29, in which the transfer means (7, 107, 8, 108), configured to indirectly move the molten salt liquid enriched in aluminum chloride and / or the electrolyte depleted in aluminum chloride, contain one or more intermediate volumes (volume) (25), configured to mix the molten salt liquid enriched in aluminum chloride and the electrolyte depleted in aluminum chloride, and / or regulate the temperature of the molten salt liquid enriched in aluminum chloride and / or the electrolyte depleted in aluminum chloride.

31. The device according to item 30, in which one or more intermediate volumes (volume) (25) are made with the possibility of partial or complete solidification of the molten salt liquid enriched with aluminum chloride, or the electrolyte depleted in aluminum chloride, or a mixture thereof.

32. The device according to any one of paragraphs. 26-29, in which the transfer means (7, 107, 8, 108), configured to directly move the molten salt liquid enriched with aluminum chloride and / or the electrolyte depleted in aluminum chloride, contain pipelines for fluidly connecting the absorption unit (5, 35, 75) and the electrolytic cell unit (9), optionally, through one or more intermediate volumes (volume) (25), configured to mix the molten salt liquid enriched with aluminum chloride and the electrolyte depleted in aluminum chloride, and also, optionally, to regulate the temperature of the resulting mixture.

33. The device according to any one of claims 30 or 32, in which the transfer means (7, 107, 8, 108) intended for transferring the electrolyte depleted in aluminum chloride from the block (9) of the electrolytic cell to the absorption block (5, 35, 75) are designed with the possibility of intermediate mixing of the electrolyte depleted in aluminum chloride with the flow of molten salt liquid enriched in aluminum chloride in one or more mixing volume(s) (25) to form a liquid single-phase flow moved to the absorption block (5, 35, 75).

34. A device according to any one of paragraphs 26-33, in which gaseous chlorine is extracted from the electrolytic cell block (9) through the outlet (11) and returned to the chlorination reactor vessel (1).

35. The device according to any one of paragraphs 26-34, further comprising means for collecting and passing gaseous CO2 from the vessel (1) of the chlorination reactor and / or the absorption unit (5, 35, 75) into the reactor (20), in which gaseous CO2 is processed and converted into gaseous CO and O2.

36. The device according to claim 35, comprising means for feeding said gaseous CO into the vessel (1) of the chlorination reactor.

37. A method for producing raw materials containing aluminum chloride for the electrolytic production of aluminum from aluminum chloride in an electrolytic cell with a molten salt electrolyte, wherein the method includes the following steps: (a) chlorinating the aluminium-containing feedstock by reacting it with chlorine gas and a carbonaceous reducing agent, CO and / or phosgene, to form a product gas stream containing aluminium chloride gas, CO2 gas and any unreacted reactants and incidental impurities; and (b) passing all or part of the product gas stream containing at least gaseous aluminium chloride and gaseous CO2 from the chlorination step (a) into an absorption unit containing a molten salt liquid in which gaseous aluminium chloride is at least partially absorbed, thereby forming a molten salt liquid enriched in aluminium chloride, wherein gaseous CO2 and any other gaseous components that are not absorbed by the molten salt liquid are withdrawn from the absorption unit and, optionally, processed in one or more processing unit(s).

38. The method of claim 37, wherein the aluminum-containing feedstock is a feedstock containing aluminum oxide.

39. The method of claim 38, wherein the raw material containing aluminum oxide is one or more types of raw material selected from the group consisting of aluminum oxide (Al2O3), aluminum oxide ore, or aluminum oxide clay mineral.

40. The method according to any one of claims 37-39, wherein the carbon-containing reducing agent is selected from carbon, gaseous CO, gaseous CH4, gaseous CCl4 and COCl2.

41. The method according to any one of paragraphs 37-40, in which the molten salt liquid located in the absorption unit is a mixture of molten salts containing aluminum chloride and one or more salt(s) selected from the group consisting of alkali metal chloride and alkaline earth metal chloride, as well as random impurities.

42. The method according to claim 41, wherein the alkali metal chloride is one or more salts selected from LiCl, NaCl and KCl, and the alkaline earth metal chloride is one or more salts selected from MgCl2 and CaCl2.

43. The method according to claim 42, wherein the mixture of molten salts contains a greater amount of alkali metal chloride salts than alkaline earth metal chloride salts.

44. The method according to any one of paragraphs 37-43, in which the concentration of aluminum chloride in the molten salt liquid located in the absorption unit is from 45 to 90% by weight, with the remainder essentially being said molten salt mixture of alkali metal chloride and / or alkaline earth metal chloride.

45. The method according to any one of paragraphs 37-44, in which the composition of the molten salt liquid, with the exception of aluminum chloride, corresponds to the composition of the molten salt electrolyte to which the said raw material is to be added.

46. ​​The method according to any one of paragraphs 37-45, in which the molten salt electrolyte depleted in aluminum chloride is moved to the absorption unit.

47. The method according to any one of paragraphs 37-46, in which the molten salt liquid enriched with aluminum chloride is moved from the absorption unit to the electrolytic cell through one or more intermediate volumes.

48. The method according to any one of paragraphs 37-47, in which the molten salt electrolyte depleted in aluminum chloride is transferred from the electrolytic cell to the absorption unit through one or more intermediate volumes.

49. The method according to any one of paragraphs 37-48, in which the gaseous medium in the absorption unit contains a chlorinating reagent selected from the group consisting of a mixture of gaseous chlorine and gaseous carbon monoxide, gaseous phosgene, gaseous carbon tetrachloride, a mixture of gaseous methane and / or carbon and gaseous chlorine.

50. The method according to any one of paragraphs. 37-49, further comprising collecting and passing gaseous CO2 exiting the chlorination stage (a) and / or the absorption stage (b) into a reactor in which CO2 is decomposed to form gaseous CO, and also feeding gaseous CO to the chlorination stage (a).

51. A device for implementing a method for producing raw materials containing aluminum chloride, intended for the electrolytic production of aluminum from aluminum chloride in an electrolytic cell with a molten salt electrolyte, comprising: a chlorination reactor vessel (1) comprising a feed channel for an aluminium-containing raw material (2), a feed channel for a chlorinating gas (4) and a feed channel for a reducing agent (3), as well as an outlet (13) for a gas stream (14) of products containing at least gaseous aluminium chloride and gaseous CO2; an absorption unit (5, 35, 75) comprising an inlet (22) for receiving all or part of the product gas stream (14) coming from the chlorination reactor vessel (1), wherein the absorption unit (5, 35, 75) contains a molten salt liquid (6) in which gaseous components of the product gas stream are partially absorbed and thereby form a molten salt liquid enriched in aluminum chloride, and comprising a gas outlet (12, 33, 73) for extracting gaseous CO2 and any gases not absorbed by the molten salt liquid in the absorption unit (5, 35, 7); and means (7, 8) for moving molten salt liquid enriched with aluminum chloride into the electrolytic cell through one or more intermediate volumes (25).

52. The device according to claim 51, wherein the absorption unit is a bubble column or vessel containing means (23) for distributing the gas flow of products in the molten salt liquid (6).

53. The apparatus of claim 51, wherein the absorption unit is a counter-current absorption unit comprising at least an inlet (36) for molten salt electrolyte depleted in aluminum chloride and an outlet (34) for molten salt liquid enriched in aluminum chloride; means (30) configured to circulate molten salt liquid (6) in the counter-current absorption unit; an inlet (32) for a product gas stream and an outlet (33) for extracting gaseous CO2 and any gases not absorbed by the molten salt liquid, wherein the direction (37) of flow of the product gas stream is formed opposite to the direction (31) of flow of the molten salt liquid.

54. The apparatus of claim 51, wherein the absorption unit is a tray absorption tower (75) having a plurality of absorption plates (76) arranged vertically and at a distance from each other in the absorption tower, comprising an inlet (72) for a product gas stream located below a lower plate, and an inlet for an electrolyte depleted in aluminum chloride located above an upper plate, and furthermore an outlet (73) located at the top of the absorption tower for extracting gaseous CO2 and any other gases not absorbed by the molten salt liquid (6), and an outlet (74) for molten salt liquid (78) enriched in aluminum chloride at the bottom of the absorption tower.

55. The device according to any one of paragraphs 51-54, further comprising means for collecting and passing gaseous CO2 from the chlorination reactor vessel and / or the absorption unit (5, 35, 75) into the reactor (20), in which gaseous CO2 is processed and converted into gaseous CO, which is recirculated into the chlorination reactor vessel (1) via a transfer line (16).