Method for recycling chromium oxide and forming chromium-alloy steel

Patent metadata

Field	Value
Publication number	US-2022170124-A1
Application number	US-202017432370-A
Country	US
Kind code	A1
Filing date	Mar 17, 2020
Priority date	Apr 1, 2019
Publication date	Jun 2, 2022
Grant date	—

Abstract

Disclosed are processes for recycling chromium oxide and producing chromium-alloy steel. Chromium oxide is reduced to metallic chromium and metallic chromium is mixed with steel to form chromium-alloy steel.

First claim

1 . A process for recycling chromium oxide and forming chromium-alloy steel, the process comprising:
adding an effective amount of a first composition comprising chromium oxide to a second composition comprising molten steel; and reducing the chromium oxide under conditions suitable to form metallic chromium, wherein the metallic chromium gets mixed with the molten steel to form chromium-alloy steel.

2 . The process of claim 1 , wherein the chromium oxide is chromium (III) oxide (Cr 2 O 3 ).

3 . The process of claim 2 , wherein the first composition further comprises alumina.

4 . The process of claim 3 , wherein the first composition comprises 10 to 25 wt. % Cr 2 O 3 and 70 to 85 wt. % alumina.

5 . The process of claim 4 , wherein the first composition further comprises 0 to 5 wt. % SiO 2 and K 2 O.

6 . The process of claim 1 , to wherein the first composition is a spent catalyst.

7 . The process of claim 1 , wherein in step (b) the chromium oxide is reduced by aluminum and the process comprises adding aluminum to the second composition.

8 . The process of claim 7 , wherein the aluminum is added to the second composition before, during, and/or after addition of the first composition to the second composition.

9 . The process of claim 7 , wherein at least a portion of the aluminum added reduces the chromium oxide added, to form the metallic chromium and alumina and at least a portion of the aluminum added reacts with dissolved oxygen in the molten steel, to form alumina.

10 . The process of claim 7 , wherein the aluminum is added as an aluminum dross and/or an aluminum wire.

11 . The process of claim 1 , wherein the step (b) conditions comprise a temperature of 1200 to 2000° C.

12 . The process of claim 1 , to wherein the second composition comprises a slag on a top portion of the molten steel.

13 . The process of claim 12 , wherein in step (a) the first composition is added to the slag.

14 . The process of claim 12 , further comprising adding lime to the slag.

15 . The process of claim 12 , wherein the slag absorbs at least a portion of the alumina formed and added during the process.

16 . The process of claim 1 , to wherein the method further comprises purging an argon containing gas from a bottom portion of the molten steel.

17 . The process of claim 1 , wherein the process is performed during a secondary steel making process.

18 . The process of claim 17 , wherein the process is performed in a ladle furnace.

19 . The process of claim 1 , the process further comprises adding one or more metals to the second composition wherein the one or more metals gets mixed with the molten steel to form one or more metals-chromium-alloy steel.

20 . The process of claim 19 , wherein the one or more metals is selected from the group consisting of molybdenum, cobalt, copper, bismuth, titanium, tungsten, vanadium, manganese and nickel.

Assignees

• Sabic Global Technologies Bv

Inventors

• Alharbi Mansour Nasser
• Almutairi Sami Muteib
• Tadiboyina Malleswara Rao

Classifications

• C22C38/18

  containing chromium · CPC title

• C21C5/5264

  Manufacture of alloyed steels including ferro-alloys · CPC title

• C21C5/54

  Processes yielding slags of special composition · CPC title

• C21C7/0075

  Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle · CPC title

• C21C7/0006 Primary

  Adding metallic additives · CPC title