Carbon dioxide sequestration through formation of group-2 carbonates and silicon dioxide
The present invention relates to carbon dioxide sequestration, including processes in which group-2 silicates are used to remove carbon dioxide from waste streams to form corresponding group-2 carbonates and silica.
1. A method of sequestering carbon dioxide produced by a source, comprising:
(a) obtaining a hydroxide salt in an aqueous mixture:
(b) admixing the hydroxide salt with carbon dioxide produced by the source under conditions suitable to form a first carbonate salt in a first admixture;
(c) chlorinating a group-2 silicate mineral with hydrochloric acid under conditions suitable to form a corresponding group-2 chloride salt, water, and silicon dioxide;
(d) admixing the group-2 chloride salt with the first carbonate salt under conditions suitable to form a group-2 carbonate salt in a second admixture; and
(e) separating said group-2 carbonate salt from the admixture,
wherein the reaction of step (d) occurs in an electrochemical cell which generates a first source of electrical energy, and whereby the carbon dioxide is sequestered into a mineral product form.
2. The method of claim 1 , further comprising:
(f) obtaining a second chloride salt; and
(g) reacting the second chloride salt under chloralkali conditions to form products comprising chlorine, hydrogen and a hydroxide salt.
3. The method of claim 2 , where some or all of the hydroxide salt in step (b) is obtained from step (g).
4. The method of claim 2 , further comprising:
(h) obtaining chlorine; and
(i) liquefying the chlorine under photolytic conditions to form hydrogen chloride.
5. The method of claim 4 , where some or all of the chlorine in step (h) is obtained from step (g).
6. The method of claim 4 , where some or all of the hydrogen chloride of step (i) is used to chlorinate the group-2 silicate mineral in step (c).
7. The method of claim 1 , where step (d) further comprises:
(d)(1) reacting the first carbonate salt with a proton source under conditions suitable to form a first bicarbonate salt; and
(d)(2) reacting the first bicarbonate salt with the group-2 chloride salt to form the group-2 carbonate salt.
8. The method of claim 7 , where the reaction of step (d)(2) further comprises the formation of a second chloride salt.
9. The method of claim 8 , where some or all of the second chloride salt in step (f) is obtained from step (d)(2).
10. The method of claim 1 , where the first source of electrical energy is generated with greater than 70% efficiency based on the theoretical maximum potential of the electrochemical cell.
11. The method of claim 1 , where some or all of the first source of energy is used to drive a part of the reaction of step (g).
12. The method of claim 2 , further comprising:
(j) using some or all of the hydrogen of step (g) to generate a second source of energy.
13. The method of claim 12 , where some or all of the second source of energy is used to drive a part of the reaction of step (g).
14. The method of claim 1 , where some or all of the hydroxide salt is sodium hydroxide.
15. The method of claim 1 , where some or all of the first carbonate salt is sodium carbonate.
16. The method of claim 1 , where some or all of the group-2 silicate mineral is a group-2 inosilicate.
17. The method of claim 1 , where some or all of the group-2 silicate mineral is CaSiO 3 .
18. The method of claim 1 , where some or all of the group-2 silicate mineral is MgSiO 3 .
19. The method of claim 1 , where some or all of the group-2 chloride salt is CaCl 2 .
20. The method of claim 1 , where some or all of the group-2 chloride salt is MgCl 2 .
21. The method of claim 1 , where some or all of the group-2 carbonate salt is CaCO 3 .
22. The method of claim 1 , where some or all of the group-2 carbonate salt is MgCO 3 .
23. The method of claim 2 , where some or all of the second chloride salt is NaCl.
24. The method of claim 4 , where the photolytic condition comprises radiation having a wavelength from about 200 nm to about 400 nm.
25. The method of claim 24 , where the wavelength is about 254 nm.
26. The method of claim 24 , where the wavelength is about 363 nm.
27. The method of claim 1 , where obtaining the hydroxide comprises:
(a)(1) obtaining a group-1 or group-2 salt;
(a)(2) admixing the salt with acid and water, acid and steam, or acid, water, and steam to produce a protonated brine solution; and
(a)(3) electrolyzing the protonated brine solution to produce a hydroxide.