Blend composition comprising petroleum coke and pyrolytic carbon for electrodes

Patent metadata

Field	Value
Publication number	US-12486587-B2
Application number	US-201917250390-A
Country	US
Kind code	B2
Filing date	Jul 15, 2019
Priority date	Jul 19, 2018
Publication date	Dec 2, 2025
Grant date	Dec 2, 2025

Abstract

A blend composition including a mixture of (i) petroleum coke in a content of 20 to 99 weight-%; and (ii) pyrolytic carbon in a content of 1 to 80 weight-%, in view of the total weight of the blend composition, wherein the blend composition contains at least two particle size fractions: (i) granular above 0.5 mm and (ii) fines below 0.5 mm, and wherein pyrolytic carbon is at least present in the granular size fraction, an electrode recipe, and the use of the electrode as an anode in a process of making aluminum.

First claim

The invention claimed is:

1 . An electrode blend composition, comprising:
a mixture of (i) petroleum coke in a content of 20 to 99 weight-%; and (ii) pyrolytic carbon in a content of 1 to 80 weight-%, in view of the total weight of the blend composition, wherein the blend composition contains at least two particle size fractions: (i) granular above 0.5 mm and (ii) fines below 0.5 mm, wherein pyrolytic carbon is at least present in the granular size fraction, wherein said pyrolytic carbon is produced by decomposition of gaseous hydrocarbon compounds at a temperature of 1000 to 2500K and by deposition of said pyrolytic carbon on carbon granules, wherein said pyrolytic carbon has a crystal size in the range of 20 to 60 Å, wherein said pyrolytic carbon is present in the granular size fraction having a particle size of 4-2 mm and/or 8-4 mm, and wherein at least 50 weight-% of the total pyrolytic carbon of the blend composition is in the granular fraction.

2 . The blend composition of claim 1 , wherein the content of said petroleum coke is of 70 to 95 weight-% and the content of said pyrolytic carbon is of 5 to 30 weight-%, in view of the total weight of the blend composition.

3 . The blend composition of claim 1 , wherein at least 70 weight-% of the total pyrolytic carbon of the blend composition is in the granular fraction.

4 . The blend composition of claim 1 , wherein said blend composition contains at least three particle size fractions:
(i) coarse above 4 mm, (ii) intermediate between 4 and 0.5 mm, wherein the coarse and intermediate fractions comprise said granular size fraction, and (iii) said fines below 0.5 mm, and wherein pyrolytic carbon, which has a size between 4 and 0.5 mm, is at least present in the intermediate fraction and/or pyrolytic carbon which has a size above 4 mm is present in the coarse fraction.

5 . The blend composition of claim 4 , wherein at least 30 weight-% of the total pyrolytic carbon of the blend composition is in the intermediate size fraction.

6 . The blend composition of claim 4 , wherein 40 to 100 weight-% of the total pyrolytic carbon of the blend composition is in the intermediate size fraction, 40 to 0 weight-% is in the coarse size fraction, and 20 to 0 weight-% is in the fine fraction.

7 . The blend composition of claim 1 , wherein a density of said pyrolytic carbon is in the range of 1.8 to 2.2 g/cc.

8 . The blend composition of claim 1 , wherein the crystal size of said pyrolytic carbon is in the range of 30 to 50 Å.

9 . The blend composition of claim 1 , wherein the petroleum coke comprises calcined petroleum coke, and wherein a sulfur content is in the range 1.5 to 7.0 weight %, in view of a total weight of the petroleum coke.

10 . The blend composition of claim 1 , wherein the specific surface area of the pyrolytic carbon is in the range of 0.001 to 5 m 2 /g.

11 . The blend composition of claim 1 , wherein the porosity of the pyrolytic carbon is under 15%.

12 . The blend composition of claim 1 , wherein the content of said petroleum coke is 40 to 98 weight-% and the content of said pyrolytic carbon is 2 to 60 weight-%.

13 . The blend composition of claim 1 , wherein 90 to 100 weight-% of the total pyrolytic carbon of the electrode composition is in the granular fraction.

14 . The blend composition of claim 1 , wherein said pyrolytic carbon is produced by decomposition of natural gas at a temperature of 1100 to 1300° C.

15 . A method of making the blend composition of claim 1 , the method comprising:
mixing the pyrolytic carbon and the petroleum coke.

16 . An electrode recipe, comprising:
a mixture of (i) the blend composition of petroleum coke and pyrolytic carbon according to claim 1 , (ii) butts and/or scrap, and (iii) a binder material.

17 . The electrode recipe of claim 16 , wherein 35 to 95 weight-% of the total weight of the electrode recipe is the blend composition, 0 to 40 weight % of the total weight of the electrode recipe are the butts and/or scraps, and 5 to 25 weight-% of the total weight of the electrode recipe is the binder material.

18 . A method of making the electrode recipe of claim 1 , the method comprising:
preheating said blend composition and the butts and/or scraps, and mixing said preheated mixture with a binder.

19 . A method of making a carbon electrode, suitable as an anode in an aluminum reduction cell, the method comprising:
mixing the blend composition according to claim 1 with butts and/or scrap and a binder material at an elevated temperature to form a paste, and baking said solid body at an elevated temperature to form the carbon electrode.

20 . A carbon electrode, suitable as an anode in an aluminum reduction cell, which comprises a blend composition comprising a mixture of (i) petroleum coke in a content of 20 to 99 weight-% and (ii) pyrolytic carbon in a content of 1 to 80 weight-%, in view of the total weight of the blend composition,
wherein the blend composition contains at least two particle size fractions: (i) granular above 0.5 mm and (ii) fines below 0.5 mm, and wherein pyrolytic carbon is at least present in the granular size fraction, wherein said pyrolytic carbon is produced by decomposition of gaseous hydrocarbon compounds at a temperature of 1000 to 2500K and by deposition of said pyrolytic carbon on carbon granules, wherein said pyrolytic carbon has a crystal size in the range of 20 to 60 k, wherein said pyrolytic carbon is present in the granular size fraction having a particle size of 4-2 mm and/or 8-4 mm, and wherein at least 50 weight-% of the total pyrolytic carbon of the blend composition is in the granular fraction.

21 . A method of making aluminum, comprising:
electrolyzing aluminum oxide in an aluminum reduction cell comprising the carbon electrode according to claim 20 as a carbon anode.

Assignees

• Basf Se

Inventors

• Scheiff Frederik
• Leduc Marc
• Bode Andreas
• Eichhorn Sabine
• Daloz William
• Wyss Julien

Classifications

• C25B11/02

  characterised by shape or form · CPC title

• C25B1/00

  Electrolytic production of inorganic compounds or non-metals · CPC title

• C25B11/043 Primary

  Carbon, e.g. diamond or graphene · CPC title

• C04B2235/96

  Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance · CPC title

• C04B2235/77

  Density · CPC title