Process for synthesis of calcium oxide

Patent metadata

Field	Value
Publication number	US-9297082-B2
Application number	US-201214361911-A
Country	US
Kind code	B2
Filing date	Nov 30, 2012
Priority date	Dec 1, 2011
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

The present invention relates to processes for making calcium oxide electrolytically using calcium carbonate as a starting material. In a direct process, the present invention involves heating calcium carbonate to a temperature greater than its melting point or heating a molten mixture containing calcium carbonate; and subjecting the molten calcium carbonate or molten mixture to electrolysis to generate calcium oxide and oxygen, and a reduced carbon product. In an indirect process, the present invention involves heating solid calcium carbonate in a closed container to cause thermal decomposition to calcium oxide, and directing the evolved hot carbon dioxide byproduct into a molten carbonate solution, and subjecting the hot carbon dioxide molten mixture to electrolysis to generate solid carbon and oxygen, and a reduced carbon product.

First claim

What is claimed is:

1. A process for producing calcium oxide comprising the step of electrolyzing a molten mixture containing calcium carbonate in an electrolysis vessel to produce calcium oxide, oxygen, and a reduced carbon product, wherein the calcium oxide collects on the bottom of the electrolysis vessel.

2. The process of claim 1 , wherein the calcium carbonate is dissolved in the molten mixture subsequent to or prior to electrolysis.

3. The process of claim 2 , wherein the molten mixture further comprises lithium carbonate, potassium carbonate, sodium carbonate, barium carbonate, or combinations thereof.

4. The process of claim 2 , wherein the molten mixture comprises lithium oxide.

5. The process of claim 1 , wherein the reduced carbon product is carbon.

6. The process of claim 1 , wherein the reduced carbon product is carbon monoxide.

7. The process of claim 1 , wherein the calcium oxide is a precipitate.

8. The process of claim 1 , wherein the electrolysis vessel is exposed to the atmosphere.

9. The process of claim 1 , wherein the electrolysis is conducted with a carbon dioxide pressure of less than about 10 atmosphere.

10. The process of claim 1 , wherein the electrolysis is conducted with a carbon dioxide pressure of greater than about 10 atmosphere.

11. The process of claim 1 , wherein the energy used to electrolyze the molten calcium carbonate is obtained from nuclear, solar, wind, or hydroelectric energy.

12. The process of claim 1 , further comprising collecting the calcium oxide from the bottom of the electrolysis vessel.

13. A process for producing calcium oxide comprising heating calcium carbonate in a vessel to produce calcium oxide and hot carbon dioxide gas; directing said hot carbon dioxide gas into a molten carbonate; and electrolyzing said molten carbonate to generate oxygen and a reduced carbon product, wherein the calcium oxide collects on the bottom of the vessel.

14. The process of claim 13 , wherein the reduced carbon product is solid carbon.

15. The process of claim 13 , wherein the reduced carbon product is carbon monoxide.

16. The process of claim 13 , wherein said molten carbonate comprises lithium carbonate, potassium carbonate, sodium carbonate, barium carbonate, lithium oxide, potassium oxide, sodium oxide, barium oxide, or combinations thereof.

17. The process of claim 13 , wherein said molten carbonate is heated by solar thermal energy.

18. The process of claim 13 , wherein said electrolysis is powered by non-fossil fuel generated electricity.

19. The process of claim 18 , wherein said non-fossil fuel generated electricity is generated by renewable energy.

20. The process of claim 18 , wherein said non-fossil fuel generated electricity is produced by nuclear, solar energy, wind, or hydroelectric energy.

21. The process of claim 13 , wherein the hot carbon dioxide gas is at a temperature of greater than about 900° C.

22. The process of claim 13 , further comprising collecting the calcium oxide from the bottom of the vessel.

Assignees

• Univ George Washington

Inventors

• Licht Stuart

Classifications

• Y02P20/133

  Renewable energy sources, e.g. sunlight · CPC title

• C25B1/18 Primary

  Alkaline earth metal compounds or magnesium compounds · CPC title

• C01F11/06

  of carbonates · CPC title

• C01B32/50

  Carbon dioxide · CPC title

• C01B32/05

  Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30 · CPC title