Production of low carbon footprint magnesia

Patent metadata

Field	Value
Publication number	US-2022332596-A1
Application number	US-202217849862-A
Country	US
Kind code	A1
Filing date	Jun 27, 2022
Priority date	Jul 27, 2016
Publication date	Oct 20, 2022
Grant date	—

Abstract

A process for producing magnesia can include contacting CO2-containing emissions with a magnesium-containing material to produce magnesium carbonate; subjecting the magnesium carbonate to calcination to produce a CO2 by-product and magnesia; and recycling at least a portion of the CO2 by-product for contacting the magnesium-containing material to produce the magnesium carbonate. The magnesium-containing material can include mining residues, such as phyllosilicate or chrysotile mining residue, and the magnesium carbonate produced can include precipitated nesquehonite that is subjected to calcination to produce the magnesia.

First claim

1 . A process for producing magnesia, comprising:
contacting CO 2 -containing emissions with a magnesium-containing material to produce magnesium carbonate; subjecting the magnesium carbonate to calcination to produce a CO 2 by-product and magnesia; and recycling at least a portion of the CO 2 by-product for contacting the magnesium-containing material to produce the magnesium carbonate.

2 . The process of claim 1 , wherein the step of contacting further comprises providing the magnesium-containing material in an aqueous slurry and contacting the CO 2 -containing emissions and the CO 2 by-product with the aqueous slurry.

3 . The process of claim 2 , further comprising:
in the contacting step, producing a carbonate loaded slurry comprising precipitable carbonates and substantially free of precipitated alkaline earth metal carbonates; separating the carbonate loaded slurry into an aqueous phase comprising the precipitable carbonates and a solid phase; precipitating the magnesium carbonates from the aqueous phase; and separating the magnesium carbonates from the aqueous phase.

4 . The process of any one of claims 1 to 3 , wherein the CO 2 -containing emissions comprise combustion gas from the magnesia production facility.

5 . The process of claim 4 , wherein combustion gas is derived from the calcination step.

6 . The process of claim 4 or 5 , wherein the combustion gas is derived from a heat activation step of the magnesium-containing material prior to contacting with the CO 2 -containing emissions.

7 . The process of any one of claims 4 to 6 , wherein the CO 2 used to contact the magnesium-containing material is exclusively obtained from the magnesia production facility.

8 . The process of any one of claims 1 to 6 , wherein the CO 2 -containing emissions comprise emissions from a separate emission source.

9 . The process of any one of claims 1 to 8 , further comprising:
subjecting the magnesium-containing material to heat activation pre-treatment prior to contacting with the CO 2 -containing emissions.

10 . The process of claim 9 , wherein the heat activation pre-treatment is performed at a temperature from approximately 600 to 700 degrees Celsius.

11 . The process of claim 10 , wherein the heat activation pre-treatment is performed for a duration of approximately 20 to 60 minutes.

12 . The process of any one of claims 9 to 11 , wherein CO 2 derived from the heat activation pre-treatment is supplied to the contacting step.

13 . The process of any one of claims 1 to 12 , wherein the magnesium-containing material is contacted with a CO 2 feed stream that includes a plurality of CO 2 source streams.

14 . The process of claim 13 , further comprising controlling the relative quantity of each CO 2 source stream in the CO 2 feed stream.

15 . The process of claim 14 , wherein the controlling is performed according to pressure, temperature and/or composition of the CO 2 source streams.

16 . The process of any one of claims 13 to 15 , wherein the CO 2 feed stream further comprises CO 2 derived from an additional magnesia production train.

17 . The process of claim 16 , wherein the additional magnesia production train comprises a conventional production train.

18 . The process of any one of claims 1 to 17 , wherein the magnesium-containing material comprises serpentine or is derived from serpentinite or variants thereof.

19 . The process of any one of claims 1 to 17 , wherein the magnesium-containing material is derived from naturally occurring mineral materials.

20 . The process of claim 19 , wherein the magnesium-containing material is derived from at least one of basalt, peridotite, serpentinized peridotite, ophiolitic rock, mafic rock, ultramafic rocks, peridot, pyroxene, olivine, serpentine, magnesium oxide containing minerals, and/or brucite.

21 . The process of claim 19 or 20 , wherein the magnesium-containing material is pre-treated to produce magnesium-containing particulate material prior to carbonation, and the magnesium-containing particulate material has a magnesium content between about 1 wt % and about 35 wt %.

22 . The process of claim 21 , wherein the magnesium content is between about 10 wt % and about 30 wt %.

23 . The process of any one of claims 1 to 17 , wherein the magnesium-containing material is derived from industrial by-product material.

24 . The process of claim 23 , wherein the industrial by-product material comprises steelmaking slag and/or steelmaking worn magnesium oxide brick.

25 . The process of any one of claims 1 to 17 , wherein the magnesium-containing material is derived from mining residue.

26 . The process of claim 25 , wherein the mining residue comprises phyllosilicate mining residue and/or chrysotile mining residue.

27 . The process of claim 1 , wherein the contacting step comprises contacting the CO 2 with the magnesium-containing material in a substantially dry form in at least one carbonation unit at a carbonation temperature between about 200° C. and about 500° C. and a carbonation pressure between about 1 bar and about 20 bars, for carbonation thereof to produce magnesium carbonates and a CO 2 depleted gas.

28 . The process of any one of claims 1 to 27 , further comprising:
subjecting the magnesium-containing material to size reduction and removal of a magnetic fraction prior to carbonation.

29 . The process of claim 28 , further comprising:
grinding a starting material to provide a particle size between about 200 microns and about 1000 microns to produce a sized material; removing the magnetic fraction from the sized material to produce a non-magnetic fraction; and grinding the non-magnetic fraction to produce the magnesium-containing material having a particle size of at most 75 microns.

30 . The process of any one of claims 1 to 29 , wherein the calcination is conducted in an indirect-heating calcination unit.

31 . The process of any one of claims 1 to 29 , wherein the calcination is conducted in a direct-heating calcination unit.

32 . The process of any one of claims 1 to 31 , further comprising controlling at least one property of the CO 2 -containing gas contacted with the magnesium-containing material.

33 . The process of claim 32 , wherein the controlling comprises regulating the relative quantities of the CO 2 -containing emissions and the CO 2 by-product are used to contact the magnesium-containing material.

34 . The process of claim 32 or 33 , wherein the controlling is performed to control gas pressure, gas temperature and/or CO 2 content of the CO 2 -containing gas contacted with the magnesium-containing material.

35 . The process of any one of claims 1 to 34 , further comprising one or more features of any one of the magnesium carbonate production methods as described herein.

36 . A process for producing magnesia, comprising:
contacting a CO 2 -containing gas with a magnesium-containing material to produce magnesium carbonate; subjecting the magnesium carbonate to calcination to produce a CO 2 by-product and magnesia; and recycling at least a portion of the CO 2 by-product as at least part of the CO 2 -containing gas for c

Assignees

• Inst Nat Rech Scient

Inventors

• Mercier Guy
• Pasquier Louis-César
• Kemache Nassima
• Cecchi Emmanuelle
• Blais Jean-François

Classifications

• C01F5/06 Primary

  by thermal decomposition of magnesium compounds (calcining magnesite or dolomite C04B2/10) · CPC title

• C01F5/02 Primary

  Magnesia · CPC title

• C01B32/50

  Carbon dioxide · CPC title

• C01F5/24

  Magnesium carbonates · CPC title