Methods and systems for utilizing calcium compound from calcined limestone

1. A method comprising:

a) calcining limestone to form carbon dioxide and calcium compound comprising calcium oxide, wherein the limestone comprises magnesium carbonate, and wherein the calcium oxide comprises soft burnt lime;

b) treating the calcium compound with N-containing salt in water to produce an aqueous solution comprising calcium salt and solid; and

c) contacting the aqueous solution comprising calcium salt and solid with the carbon dioxide to produce a precipitation material comprising calcium carbonate and solid wherein the calcium carbonate comprises vaterite.

2. The method of claim 1 , wherein the treating step further comprises adding anhydrous ammonia or an aqueous solution of ammonia.

3. The method of claim 1 , wherein the N-containing salt is N-containing inorganic salt, N-containing organic salt, or combination thereof.

4. The method of claim 1 , wherein the N-containing salt is N-containing inorganic salt selected from the group consisting of ammonium halide, ammonium acetate, ammonium sulfate, ammonium sulfite, ammonium nitrate, ammonium nitrite, and combinations thereof.

5. The method of claim 1 , wherein the N-containing salt is ammonium chloride.

6. The method of claim 1 , wherein the N-containing salt is N-containing organic salt that has N-containing organic compound selected from the group consisting of aliphatic amine, alicyclic amine, heterocyclic amine, and combinations thereof.

7. The method of claim 1 , wherein molar ratio of the N-containing salt:calcium compound is between about 0.5:1 to 4:1 by weight.

8. The method of claim 1 , further comprising removing and optionally recovering ammonia and/or N-containing salt using one or more steps of (i) recovering a gas exhaust stream comprising ammonia during the treating and/or the contacting step; (ii) wherein the supernatant aqueous solution comprises residual N-containing salt and further comprising recovering the residual N-containing salt from the supernatant aqueous solution; and (iii) wherein the precipitation material comprises residual N-containing salt and further comprising removing and optionally recovering the residual N-containing salt from the precipitation material.

9. The method of claim 8 , further comprising recovering the residual N-containing salt from the supernatant aqueous solution using recovery process selected from the group consisting of thermal decomposition, pH adjustment, reverse osmosis, multi-stage flash, multi-effect distillation, vapor recompression, distillation, and combinations thereof and/or further comprising recovering the residual N-containing salt from the precipitation material comprises heating the precipitation material between about 150-360° C. to evaporate the N-containing salt from the precipitation material with optional recovery by condensation of the N-containing salt.

10. The method of claim 8 , wherein the step of recovering the gas exhaust stream comprising ammonia comprises subjecting the gas exhaust stream comprising ammonia to a scrubbing process wherein the scrubbing process comprises scrubbing the gas exhaust stream comprising ammonia with the carbon dioxide from the industrial process and water.

11. The method of claim 8 , wherein the step of recovering the gas exhaust stream comprising ammonia comprises subjecting the gas exhaust stream comprising ammonia to a scrubbing process wherein the scrubbing process comprises scrubbing the gas exhaust stream comprising ammonia with hydrochloric acid and water to produce a solution of ammonium chloride.

12. The method of claim 1 , wherein the vaterite is reactive vaterite or stable vaterite.

13. The method of claim 12 , further comprising adding water to the precipitation material comprising reactive vaterite and transforming the vaterite to aragonite wherein the aragonite sets and hardens to form cement or cementitious product.

14. The method of claim 13 , wherein the cementitious product is aggregate; building material; or formed building material selected from masonry unit, construction panel, conduit, basin, beam, column, slab, acoustic barrier, insulation material, and combinations thereof.

15. The method of claim 1 , wherein the solids comprise carbon, silica, iron oxide, aluminum oxide, or combination thereof.

16. The method of claim 1 , wherein the contracting step is under one or more precipitation conditions comprising pH of between 7-8.5 of the aqueous solution, temperature of the solution between 20-80° C., residence time of between 15-60 minutes, or combinations thereof.

17. A product formed by the method according to claim 1 .

18. The method of claim 1 , wherein the calcium oxide further comprises underburnt lime, dead burnt lime, or combination thereof.

19. The method of claim 1 , further comprising adding an additive to the aqueous solution or to the precipitation material, wherein the additive is selected from the group consisting of fatty acid ester, sodium decyl sulfate, lauric acid, sodium salt of lauric acid, urea, citric acid, sodium salt of citric acid, phthalic acid, sodium salt of aspartic acid, magnesium chloride, acetic acid, sodium salt of acetic acid, glutamic acid, sodium salt of glutamic acid, strontium chloride, gypsum, lithium chloride, sodium chloride, glycine, sodium citrate dehydrate, sodium bicarbonate, magnesium sulfate, magnesium acetate, sodium polystyrene, sodium dodecylsulfonate, poly-vinyl alcohol, and combination thereof.

20. The method of claim 1 , wherein the vaterite is unimodal, bimodal, or multimodal distribution of a particulate composition with an average particle size of between 0.1-100 micron.

21. The method of claim 1 , further comprising blending the precipitation material with Ordinary Portland Cement (OPC), aggregate, or combination thereof.

22. The method of claim 1 , further comprising mixing the precipitation material with one or more admixture selected from the group consisting of set accelerator, set retarder, air-entraining agent, foaming agent, defoamer, alkali-reactivity reducer, bonding admixture, dispersant, coloring admixture, corrosion inhibitor, damp-proofing admixture, gas former, permeability reducer, pumping aid, shrinkage compensation admixture, fungicidal admixture, germicidal admixture, insecticidal admixture, rheology modifying agent, water repellent, reinforced material, and combination thereof.

23. The method of claim 22 , wherein the reinforced material is a fiber made of zirconia, aluminum, glass, steel, carbon, ceramic, grass, bamboo, wood, fiberglass, synthetic material, or combination thereof.