Composition for making wettable cathode in aluminum smelting

Patent metadata

Field	Value
Publication number	US-11041250-B2
Application number	US-201816140276-A
Country	US
Kind code	B2
Filing date	Sep 24, 2018
Priority date	Jul 28, 2009
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

Compositions for making wettable cathodes to be used in aluminum electrolysis cells are disclosed. The compositions generally include titanium diboride (TiB2) and metal additives. The amount of selected metal additives may result in production of electrodes having a tailored density and/or porosity. The electrodes may be durable and used in aluminum electrolysis cells.

First claim

What is claimed is:

1. A component, comprising:
0.01 to not greater than 0.45 wt. % metal additives, the balance being TiB 2 and unavoidable impurities, wherein the unavoidable impurities make up less than 2 wt. % of the component;
wherein the metal additives at least include chromium (Cr), wherein the chromium content of the component is not greater than 0.35 wt. %;
wherein the component is crack-free and has a density of at least 90% to not greater than 98% of its theoretical density, and wherein the component has an apparent porosity of 0.05% to 4%.

2. The component of claim 1 , further wherein the component comprises a geometry selected from the group consisting of: a tube, a plate, a rod.

3. The component of claim 1 , wherein the component is configured as an electrode for use in an aluminum electrolysis cell.

4. The component of claim 1 , wherein the metal additives further include one or more of Fe, Ni, Co, and W.

5. The component of claim 1 , wherein the metal additives further include one or more of Mn, Mo, Pt, and Pd.

6. An electrode for use in an aluminum electrolysis cell, the electrode comprising:
0.01 to less than 0.5 wt. % metal additives, the balance being TiB 2 and unavoidable impurities, wherein the unavoidable impurities make up less than 2 wt. % of the electrode;
wherein the metal additives at least include chromium (Cr), wherein the chromium content of electrode is not greater than 0.35 wt. %;
wherein the electrode is crack-free and has a density of at least 90% to not greater than 98% of its theoretical density, and wherein the component has an apparent porosity of 0.05% to 4%.

7. The electrode of claim 6 , wherein the electrode is configured as a cathode in an aluminum electrolysis cell.

8. A method comprising:
(a) blending a first powder comprising TiB 2 with a second powder comprising a selected amount of metal additives to make a TiB 2 composition, the TiB 2 composition comprising:
from 0.01 to not greater than 0.45 wt. % of the metal additives, the balance being TiB 2 and unavoidable impurities, wherein the unavoidable impurities make up less than 2 wt. % of the electrode, wherein the metal additives at least include chromium (Cr), wherein the chromium content of electrode is not greater than 0.35 wt. %; and
(b) producing a TiB 2 component from the TiB 2 composition;
wherein the TiB 2 component is crack-free and has a density of at least 90% to not greater than 98% of its theoretical density, and wherein the component has an apparent porosity of 0.05% to 4%.

9. The method of claim 8 , wherein the producing step further comprises:
pressing the TiB 2 composition; and
sintering the pressed TiB 2 composition to yield the TiB 2 component.

10. The method of claim 8 , wherein the method comprises forming the TiB 2 component, the TiB 2 component comprising a geometry selected from the group consisting of: a plate, a rod, and a tube.

11. The method of claim 8 , wherein the producing step further comprises:
pressureless sintering the TiB 2 composition to yield the TiB 2 component.

12. The method of claim 8 , wherein the producing step further comprises:
sintering the TiB 2 composition at a temperature of between 1400° C. to 2100° C.

13. The method of claim 12 , wherein the producing step further comprises:
pressing the TiB 2 composition at a pressure from 70 kg/cm 3 to at least 350 kg/cm 3 .

14. The method of claim 8 , wherein the metal additives further include one or more of Mn, Mo, Pt, and Pd.

15. The method of claim 8 , wherein the metal additives further include one or more of Fe, Ni, Co, and W.

16. An electrode, comprising:
0.025 to 0.10 wt. % metal additives, wherein the metal additives at least include Cr;
the balance being TiB 2 and unavoidable impurities,
wherein the unavoidable impurities make up less than 2 wt. % of the component;
wherein the component has a density of 88.9% to 98.5% of its theoretical density, and
wherein the component has an apparent porosity of 0.05% to 4%.

17. The electrode of claim 16 , wherein the metal additives further include one or more of Mn, Mo, Pt, and Pd.

18. The electrode of claim 16 , wherein the metal additives further include one or more of Fe, Ni, Co, and W.

Assignees

• Alcoa Usa Corp

Inventors

• Weirauch Douglas A
• Sworts Lance M
• Tielsch Brian J
• Dimilia Robert A

Classifications

• C22B21/00

  Obtaining aluminium · CPC title

• C25B11/04 Primary

  characterised by the material · CPC title

• C25C3/08 Primary

  Cell construction, e.g. bottoms, walls, cathodes · CPC title

• C04B35/64

  Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F}) · CPC title

• C04B35/58071

  based on titanium borides · CPC title