Selective sulfidation and desulfidation

Patent metadata

Field	Value
Publication number	US-12258672-B2
Application number	US-202017134429-A
Country	US
Kind code	B2
Filing date	Dec 27, 2020
Priority date	Feb 27, 2020
Publication date	Mar 25, 2025
Grant date	Mar 25, 2025

Abstract

Various embodiments utilize selective sulfidation and/or desulfidation for such things as ore and concentrate cracking, metal separation, compound production, and recycling. Selective sulfidation can be used to selectively convert an oxide or other material in a feedstock to a sulfide or other sulfur-containing material, and selective desulfidation can be used to selectively convert a sulfide or other sulfur-containing material in a feedstock to an oxide or other material. In some cases, the material produced by such selective sulfidation/desulfidation of the feedstock can itself be novel and/or commercially valuable, while in other cases, such selective sulfidation/desulfidation can be followed by one or more processes to extract, isolate, or concentrate the converted material.

First claim

What is claimed is:

1. A process for selective sulfidation of a target metal compound of a feedstock material within a reactor, the target metal compound consisting of a metal oxide, oxysulfide, carbonate, sulfate, or sulfide, the process comprising:
introducing a flow of sulfur-containing gas into the reactor through a gas inlet of the reactor; and
passing the flow of sulfur-containing gas through the feedstock material within the reactor while controlling a roasting atmosphere in the reactor about the feedstock material including at least a process temperature and a ratio of sulfur to sulfur dioxide chosen for selective sulfidation of the target component to produce a selectively sulfidized compound including a sulfate, oxysulfide, or sulfide of the target metal, the ratio of sulfur to sulfur dioxide being maintained above a predetermined critical ratio for such selective sulfidation of the target metal compound.

2. A process according to claim 1 , wherein the selective sulfidation is run as a continuous or semi-continuous process.

3. A process according to claim 1 , wherein the selective sulfidation includes high temperature selective sulfidation of an individual metal oxide, sulfate, carbonate, oxysulfide, or sulfide from a mixture of highly chemically-similar metal compounds in the feedstock material.

4. A process according to claim 1 , wherein controlling the roasting atmosphere further includes implementation of a carbothermically-driven sulfur reflux system by back-reacting product sulfur dioxide to control sulfide product selectivity and valency.

5. A process according to claim 4 , wherein implementing the carbothermically-driven sulfur reflux system comprises:
introducing a carbon species into the reactor during selective sulfidation to remove sulfur dioxide from the reactor and reflux it back into sulfur while producing carbon monoxide or carbon dioxide.

6. A process according to claim 1 , wherein the selective sulfidation includes at least one of:
crystallization of the target metal compound from a mixed amorphous or semi-amorphous metal compound; or
spontaneous separation of the selectively sulfidized compound upon sulfidation from a mixed metal compound due to differences in phase stability of the selectively sulfidized compound compared to the original target metal compound.

7. A process according to claim 1 , further comprising:
extracting the selectively sulfidized compound from the feedstock material.

8. A process according to claim 1 , further comprising:
using at least the selectively sulfidized compound in a subsequent molten sulfide electrolysis process.

9. A process according to claim 8 , wherein the selectively sulfidized compound includes at least one of barium sulfide or a rare earth sulfide.

10. A process according to claim 1 , wherein controlling the roasting atmosphere further includes controlling a ratio of carbon monoxide to carbon dioxide within the reactor to stabilize or react the target metal compound.

11. A process according to claim 1 , wherein controlling the roasting atmosphere further includes controlling porosity change of the feedstock material within the reactor to stabilize or react the target metal compound.

12. A process according to claim 1 , further comprising:
pre-treating the feedstock material prior to introducing the feedstock material into the reactor including at least one of calcination, dehalogenation, dephosphorization, or sulfidative sintering.

13. A system for selective sulfidation of a target metal compound of a feedstock material, the system comprising:
a reactor comprising a gas inlet and a receptacle for receiving a feedstock material containing a target metal compound consisting of a metal oxide, oxysulfide, carbonate, sulfate, or sulfide;
a source of sulfur-containing gas; and
a process controller configured to control introduction of a flow of sulfur-containing gas from the source of sulfur-containing gas into the reactor through the gas inlet of the reactor and passing of the flow of sulfur-containing gas through the feedstock material within the reactor while controlling a roasting atmosphere in the reactor about the feedstock material including at least a process temperature and a ratio of sulfur to sulfur dioxide chosen for selective sulfidation of the target component to produce a selectively sulfidized compound including a sulfate, oxysulfide, or sulfide of the target metal, the ratio of sulfur to sulfur dioxide being maintained above a predetermined critical ratio for such selective sulfidation of the target metal compound.

14. A system according to claim 13 , wherein the reactor is configured to run selective sulfidation as a continuous or semi-continuous process.

15. A system according to claim 13 , wherein the selective sulfidation includes high temperature selective sulfidation of an individual metal oxide, sulfate, carbonate, oxysulfide, or sulfide from a mixture of highly chemically-similar metal compounds in the feedstock material.

16. A system according to claim 13 , wherein controlling the roasting atmosphere further includes implementation of a carbothermically-driven sulfur reflux system that back-reacts product sulfur dioxide to control sulfide product selectivity and valency.

17. A system according to claim 16 , further comprising:
a carbon source that introduces a carbon species into the reactor during selective sulfidation to remove sulfur dioxide from the reactor and reflux it back into sulfur while producing carbon monoxide or carbon dioxide.

18. A system according to claim 13 , wherein the selective sulfidation includes at least one of:
crystallization of the target metal compound from a mixed amorphous or semi-amorphous metal compound; or
spontaneous separation of the selectively sulfidized compound upon sulfidation from a mixed metal compound due to differences in phase stability of the selectively sulfidized compound compared to the original target metal compound.

19. A system according to claim 13 , wherein controlling the roasting atmosphere further includes controlling a ratio of carbon monoxide to carbon dioxide within the reactor to stabilize or react the target metal compound.

20. A system according to claim 13 , wherein controlling the roasting atmosphere further includes controlling porosity change of the feedstock material within the reactor to stabilize or react the target metal compound.

Assignees

• Massachusetts Inst Technology

Inventors

• Allanore Antoine
• Stinn Caspar R

Classifications

• C22B1/06

  Sulfating roasting · CPC title

• C22B26/20

  Obtaining alkaline earth metals or magnesium · CPC title

• C22B59/00

  Obtaining rare earth metals · CPC title

• C25C3/34

  of metals not provided for in groups C25C3/02 - C25C3/32 · CPC title

• C22B1/11

  Removing sulfur, phosphorus or arsenic other than by roasting · CPC title