ELECTRODES FOR ALUMINUM ELECTROLYZERS AND METHODS OF THEIR MANUFACTURING

Claims

1. A method comprising: (a) shaping the TiB2 raw material into a desired shaped product, wherein the desired shaped product realizes a density of from 40% to 70% of the theoretical density of pure TiB2; and (b) obtaining a final molded product from a given molded product; wherein the production includes exposing the given molded product to an elevated temperature, wherein due to the exposure the final molded product realizes a plurality of pores and at least one of the following properties: (i) density from 85% to 98% of the theoretical density of TiB2; (ii) the average grain size is not more than 15 micrometers; (iii) intergranular porosity from 1 to 15 vol.%; (iv) the average pore size is not more than 120% of the average grain size; and (v) random grain orientation.

2. The method according to claim 1, wherein the TiB2 raw material comprises TiB2 particles, TiB2 granules and combinations thereof.

3. The method of claim 1, wherein the forming step (a) comprises one or more of pressing, rolling compaction, casting and extrusion of the TiB2 raw material to form a desired formed product.

4. The method according to claim 1, wherein step (a) of forming is completed at ambient temperature.

5. The method of any one of paragraphs 2-4, wherein the forming step (a) comprises applying a pressure of at least 5000 psi, or at least 6000 psi, or at least 7000 psi, or at least 7500 psi.

6. The method according to any one of the preceding claims, wherein the desired formed product realizes a density of at least 45%, or at least 50%, or at least 55%, or at least 58%, or at least 60%, of the theoretical density of TiB2.

7. The method according to claim 6, wherein the specified molded product realizes a density of no more than 68% of the theoretical density of TiB2.

8. The method according to claim 1, wherein step (b) of obtaining comprises: first heating a predetermined molded product at a first temperature and for a first period of time; second heating the predetermined molded product at a second temperature for a second period of time, wherein the second temperature is higher than the first temperature.

9. The method of claim 8, wherein the first temperature is at least 200°C, or at least 300°C, or at least 400°C, or at least 500°C.

10. The method according to claim 8 or 9, wherein the first period of time is at least 1 minute, or at least 10 minutes, or at least 30 minutes, or at least 60 minutes.

11. The method according to any of paragraphs 8-10, wherein the first period of time is no more than 48 hours.

12. The method according to any one of paragraphs 8-11, wherein the first temperature is no more than 1200°C.

13. The method according to any one of claims 8 to 12, wherein the second temperature is at least 1600°C, or at least 1700°C, or at least 1800°C, or at least 1825°C.

14. The method according to any one of claims 8 to 13, wherein the second period of time is at least 1 minute, or at least 10 minutes, or at least 30 minutes, or at least 1 hour, or at least 4 hours, or at least 8 hours, or at least 12 hours.

15. The method according to any of paragraphs 8-14, wherein the second period of time is no more than 96 hours.

16. The method according to any one of paragraphs 8-15, wherein the second temperature is no more than 2300°C.

17. The method according to any one of paragraphs. 8-16, wherein the first heating comprises heating from an initial temperature to a first temperature at a first heating rate, wherein the first heating rate is no more than 10°C / min, or no more than 8°C / min, or no more than 6°C / min, or no more than 5°C / min.

18. The method according to claim 17, wherein the initial temperature is the ambient temperature.

19. The method according to claim 17 or 18, wherein the second heating comprises heating from the first temperature to the second temperature at a second heating rate, wherein the second heating rate is no more than 8°C / min, or no more than 7°C / min, or no more than 6°C / min, or no more than 5°C / min.

20. The method according to any of the preceding claims, wherein the final shaped product implements at least two properties from (b)(i) to (b)(v).

21. The method according to any one of the preceding claims, wherein the final moulded product implements at least three properties from (b)(i) to (b)(v).

22. The method according to any one of the preceding claims, wherein the final shaped product implements at least four properties from (b)(i) to (b)(v).

23. The method according to any of the preceding claims, wherein the final molded product implements all the properties of (b)(i) to (b)(v).

24. The method according to any of the preceding paragraphs, wherein the final molded product realizes an average grain size of not more than 12 micrometers, or not more than 10 micrometers, or not more than 8 micrometers, or not more than 6 micrometers, or not more than 4 micrometers.

25. The method according to any of the preceding paragraphs, wherein the final molded product realizes an intergranular porosity of not more than 14 vol.% or an intergranular porosity of not more than 13 vol.%.

26. The method according to any of the preceding claims, wherein the final shaped product realizes an intergranular porosity of at least 2 vol.%, or an intergranular porosity of at least 4 vol.%, or an intergranular porosity of at least 6 vol.%, or an intergranular porosity of at least 8 vol.%.

27. The method according to any of the preceding paragraphs, wherein the final molded product realizes an average pore size of no more than 110% of the average grain size, or an average pore size of no more than 100% of the average grain size, or an average pore size of no more than 90% of the average grain size, or an average pore size of no more than 80% of the average grain size, or an average pore size of no more than 70% of the average grain size, or an average pore size of no more than 60% of the average grain size, or an average pore size of no more than 50% of the average grain size.

28. The method according to any of the preceding paragraphs, wherein the final molded product realizes an FRO intensity of no more than 3 times greater than random, or no more than 2.75 times greater than random, or no more than 2.50 times greater than random, or no more than 2.25 times greater than random, or no more than 2.00 times greater than random, or no more than 1.75 times greater than random, or no more than 1.50 times greater than random.

29. A method according to any of the preceding paragraphs, comprising: preparing TiB2 raw material for the molding stage, wherein the preparation stage includes, prior to the molding stage, spray drying the suspension to thereby obtain TiB2 granules.

30. The method according to claim 29, wherein the suspension comprises a liquid medium, wherein due to at least the dispersing agent and the binder, the TiB2 granules have at least one of: (i) D 90 no more than 200 micrometers; (ii) D 10 at least 10 micrometers; (iii) bulk density from 1.0 to 1.8 g / cm 3 ; (iv) the liquid medium content is not more than 0.5% by weight; and (v) flowability of at least 0.2 g / s.

31. The method according to claim 29, wherein before spray drying the TiB2 powder is combined with a liquid medium, wherein the suspension contains the TiB2 powder, a dispersing agent and a binder.

32. The method according to claim 29, wherein the preparation step comprises: deagglomerating the first TiB2 powder to obtain a second TiB2 powder, wherein the second TiB2 powder implements at least one of the following: (i) D 50 from 0.5 to 4.0 micrometers; (ii) surface area from 1.0 to 3.0 m 2 / G; (iii) not more than 5.0 wt.% O, or not more than 4 wt.% O, or not more than 3 wt.% O, or not more than 2.5 wt.% O, or not more than 2.0 wt.% O, or not more than 1.5 wt.% O, or not more than 1 wt.% O; (iv) not more than 5.0 wt.% C, or not more than 4 wt.% C, or not more than 3 wt.% C, or not more than 2.5 wt.% C, or not more than 2.0 wt.% C, or not more than 1.5 wt.% C, or not more than 1 wt.% C; and (v) incorrect particle morphology.

33. The method according to claim 32, wherein the second TiB2 powder is added to the liquid medium to form a suspension.

34. The method according to any of the preceding claims, wherein the final formed product is an electrode.

35. The method according to claim 34, wherein the electrode is a cathode.

36. The method according to claim 34, wherein the electrode is an anode.

37. An electrolyzer for producing aluminum, comprising an electrode according to any one of paragraphs 34-36.

38. An electrolyzer for refining aluminum, comprising an electrode according to any one of paragraphs 34-36.

39. A method comprising: using the final formed product according to any one of claims 1-33 as an electrode in an electrolytic cell for producing aluminum to produce metallic aluminum.

40. A method comprising: using the final formed product according to any one of claims 1-33 as an electrode in an electrolytic cell for refining aluminum to produce metallic aluminum.

41. A monolithic formed product of titanium diboride (TiB2) containing: (a) at least 50 vol.% TiB2; (b) at least one of the following properties: (i) density from 85% to 98% of the theoretical density of TiB2; (ii) the average grain size is not more than 15 micrometers; (iii) intergranular porosity from 1 to 15 vol.%; (iv) the average pore size is not more than 120% of the average grain size; and (v) random grain orientation.

42. A monolithic formed product of titanium diboride (TiB2) according to claim 41, wherein the monolithic formed product of titanium diboride (TiB2) has at least two of (b)(i)-(v).

43. A monolithic formed product of titanium diboride (TiB2) according to claim 41, wherein the monolithic formed product of titanium diboride (TiB2) has at least three of (b)(i)-(v).

44. A monolithic formed product of titanium diboride (TiB2) according to claim 41, wherein the monolithic formed product of titanium diboride (TiB2) has at least four of (b)(i)-(v).

45. A monolithic formed product of titanium diboride (TiB2) according to claim 41, wherein the monolithic formed product of titanium diboride (TiB2) has all of (b)(i)-(v).

46. A monolithic formed product made of titanium diboride (TiB2) according to claim 41, wherein said at least one of the properties (b)(i)-(v) is preselected.

47. A monolithic formed product made of titanium diboride (TiB2) according to claim 41, wherein the monolithic formed product made of titanium diboride (TiB2) is intended for use in an electrolyzer.

48. A monolithic formed product of titanium diboride (TiB2) according to claim 47, wherein the electrolyzer is an electrolyzer for refining aluminum.

49. A monolithic formed product of titanium diboride (TiB2) according to claim 47, wherein the electrolyzer is an electrolyzer for the production of aluminum.

50. A monolithic formed product of titanium diboride (TiB2) according to claim 41, wherein the monolithic formed product of titanium diboride (TiB2) is an electrode.

51. A monolithic molded product made of titanium diboride (TiB2) according to claim 50, wherein the electrode is a cathode.

52. A monolithic molded product made of titanium diboride (TiB2) according to claim 50, wherein the electrode is an anode.

53. A monolithic formed product made of titanium diboride (TiB2) according to claim 41, wherein the monolithic formed product made of titanium diboride (TiB2) has at least a first face and a second face, wherein the second face is adjacent to the first face or perpendicular to it.

54. A monolithic formed product made of titanium diboride (TiB2) according to claim 53, wherein the monolithic formed product made of titanium diboride (TiB2) has at least (v) a random grain orientation, wherein the random grain orientation is similarly oriented on both the first face and the second face.