Intrinsic CO2 capture process for the production of metal oxides, cement, CO2 air capture or a combination thereof

1. A process for producing captured carbon dioxide comprising:

reacting calcium carbonate with sulfur dioxide solution to directly produce solid calcium sulfite and gaseous carbon dioxide without the prior or simultaneous production of bisulfite;

thermally decomposing said calcium sulfite to produce gaseous sulfur dioxide; and

recovering gaseous sulfur dioxide by dissolving it in a solution;

wherein the gaseous carbon dioxide is captured and wherein the reaction of calcium carbonate with sulfur dioxide solution is conducted under conditions to prevent the formation of sulfate salts, wherein said conditions to prevent the formation of sulfate salts in the reaction of calcium carbonate with sulfur dioxide solution comprise gaseous diatomic oxygen concentration of less than 21 vol %.

2. The process of claim 1 wherein said thermal decomposing is conducted in a mixture with calcium carbonate.

3. The process of claim 1 wherein said thermal decomposing is conducted in a mixture comprising a clay, or silicon dioxide, or aluminum oxide, or iron oxide, or iron carbonate, or magnesium carbonate, or magnesium oxide, or a silicate, or an aluminate, or shale, or sand, or fly ash, or ash, or slag, or a sulfur oxide, or a combination thereof.

4. The process of claim 1 , wherein said gaseous diatomic oxygen concentration is less than 20,000 PPM.

5. The process of claim 1 , wherein said gaseous diatomic oxygen concentration is less than 10,000 PPM.

6. The process of claim 1 wherein the thermal decomposing further produces other gases.

7. The process of claim 1 further comprising recovering at least a portion of the gaseous sulfur dioxide resulting from said thermal decomposing by absorption of said gaseous sulfur dioxide into a sulfur dioxide-lean solution to produce a sulfur dioxide-rich solution.

8. The process of claim 1 wherein said calcium carbonate comprises limestone.

9. The process of claim 1 wherein said thermal decomposing is conducted in the presence of at least one hot gas.

10. The process of claim 9 wherein said at least one hot gas comprises a combustion gas.

11. The process of claim 10 wherein said combustion gas originated from combustion of a fuel-rich mixture comprising a ratio of a fuel to an oxidant which is equal to or greater than a stoichiometric ratio of the fuel to the oxidant for complete combustion.

12. The process of claim 10 wherein said combustion gas originated from combustion of a fuel comprising a carbonaceous fuel, or a sulfurous fuel, or a nitrogenous fuel, or a hydrogen fuel, or a combination thereof.

13. The process of claim 10 wherein said combustion gas originated from a combustion process comprising a first combustion step and a second combustion step;

wherein the first combustion step comprises combusting carbonaceous fuel; and wherein the second combustion step comprises combusting hydrogen fuel.

14. The process of claim 10 wherein said combustion gas originated from a combustion process comprising a first combustion step and a second combustion step;

wherein the first combustion step comprises combusting hydrogen fuel; and

wherein the second combustion step comprises combusting sulfurous fuel.

15. The process of claim 10 wherein said combustion gas originated from a combustion process comprising a first combustion step and a second combustion step;

wherein the first combustion step comprises combusting carbonaceous fuel; and wherein the second combustion step comprises combusting nitrogenous fuel.

16. The process of claim 10 wherein said combustion gas originated from a combustion process comprising a first combustion step and a second combustion step;

wherein the first combustion step comprises combusting carbonaceous fuel; and wherein the second combustion step comprises combusting a mixture comprising a sulfurous fuel and a nitrogenous fuel.

17. The process of claim 10 wherein said combustion gas originated from a combustion process comprising a first combustion step and a second combustion step;

wherein the first combustion step comprises combusting carbonaceous fuel; and wherein the second combustion step comprises combusting a mixture comprising a hydrogen fuel and a sulfurous fuel.

18. The process of claim 10 wherein said combustion gas originated from a combustion process comprising a first combustion step and a second combustion step;

wherein the first combustion step comprises combusting carbonaceous fuel; and wherein the second combustion step comprises combusting sulfurous fuel.

19. The process of claim 18 wherein the second combustion step reduces diatomic oxygen concentration.

20. The process of claim 18 wherein sulfur dioxide is provided in the second combustion step to makeup for sulfur dioxide loss in the process.

21. The process of claim 18 wherein said first combustion step comprises combusting the carbonaceous fuel with a diatomic oxygen-rich gas to form a diatomic oxygen-lean gas; and

wherein said second combustion step comprises combusting the sulfurous fuel with the diatomic oxygen-lean gas and to form a diatomic oxygen-ultra-lean gas.

22. The process of claim 1 further comprising recovering at least a portion of the gaseous sulfur dioxide resulting from said thermal decomposing.

23. The process of claim 22 where said recovering comprises absorbing sulfur dioxide in a wash.

24. The process of claim 22 where said recovering comprises condensing sulfur dioxide.

25. The process of claim 1 wherein the sulfur dioxide reacted with the calcium carbonate is in the form of a sulfur dioxide-rich solution and wherein the reaction with the calcium carbonate further produces a sulfur dioxide-lean solution.

26. The process of claim 25 which further comprises recovering at least a portion of the gaseous sulfur dioxide resulting from said thermal decomposing by absorption of said gaseous sulfur dioxide into the sulfur dioxide-lean solution to produce a sulfur dioxide-rich solution.