Method of preparing calcium carbonate using direct carbonation reaction

Patent metadata

Field	Value
Publication number	US-9505629-B2
Application number	US-201414461201-A
Country	US
Kind code	B2
Filing date	Aug 15, 2014
Priority date	Aug 19, 2013
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

Disclosed is a method of preparing calcium carbonate using a direct carbonation reaction. The method includes dissolving fuel gas desulfurization gypsum into an ammonia solution, performing a filtering process after making a carbonation reaction by feeding carbon dioxide into the ammonia solution in which the fuel gas desulfurization gypsum is dissolved, and performing a filtering process after precipitating the calcium carbonate by maintaining a filtered solution in a stationary state.

First claim

What is claimed is:

1. A method of preparing calcium carbonate using a direct carbonation reaction, the method comprising:
dissolving flue gas desulfurization gypsum into an ammonia solution;
performing a filtering process to obtain a filtered solution after making a carbonation reaction by feeding carbon dioxide into the ammonia solution in which the flue gas desulfurization gypsum is dissolved; and
performing a filtering process to obtain solid-phase calcium carbonate after precipitating the calcium carbonate by maintaining the filtered solution in a stationary state,
wherein a solid dosage of the flue gas desulfurization gypsum to the ammonia solution is in a range of 5 g/L to 20 g/L,
wherein the calcium carbonate includes vaterite crystals having 100% whiteness, and
wherein the direct carbonation reaction is performed at normal temperature and normal pressure.

2. The method of claim 1 , wherein an ammonia concentration in the ammonia solution is in a range of 4% by volume to 12% by volume.

3. The method of claim 1 , wherein the dissolving of the flue gas desulfurization gypsum into the ammonia solution comprises performing an agitating process at a rate in a range of 350 rpm to 450 rpm for five minutes.

4. The method of claim 1 , wherein a concentration of the flue gas desulfurization gypsum in the ammonia solution in which the flue gas desulfurization gypsum is in a range of 30 mM to 110 mM.

5. The method of claim 1 , wherein the carbon dioxide is fed at a flow rate in a range of 1 L/min to 3 L/min.

6. The method of claim 1 , wherein the carbonation reaction is performed for five minutes to 20 minutes.

7. The method of claim 1 , wherein the carbonation reaction is completed at pH 7.

8. The method of claim 1 , wherein the filtering process is performed by a 0.2 μm membrane filter.

9. The method of claim 8 , wherein the 0.2 μm membrane filter includes cellulose acetate.

10. The method of claim 1 , further comprising crystallizing the filtered solution after precipitating the calcium carbonate.

11. The method of claim 1 , further comprising adjusting a pH of the ammonia solution, in which the flue gas desulfurization gypsum is dissolved, to at least 9.0 in the carbonation reaction.

Assignees

• Korea Inst Geoscience & Mineral Resources

Inventors

• Song Kyungsun
• Jang Young-Nam
• Chae Soo-Chun

Classifications

• C01P2004/45

  Aggregated particles or particles with an intergrown morphology · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C01P2004/38

  cube-like · CPC title

• C01P2006/80

  Compositional purity · CPC title

• C01P2002/30

  Three-dimensional structures · CPC title