Stable synthetic rhodochrosite and a method for the production thereof

1. A stable rhodochrosite comprising manganese carbonate (MnCO 3 ) and 0.03-0.3 wt % of an anion or ligand of phosphoric acid (H 3 PO 4 ), pyrophosphoric acid (H 4 P 2 O 7 ), an organic acid, or a salt of such acids, or 0.03-0.3 wt % of a mixture of such anions and/or ligands.

2. The stable rhodochrosite of claim 1 , wherein the anion or ligand comprises phosphate (PO 4 3− ), pyrophosphate (P 2 O 7 4− ), citrate (C 6 H 5 O 7 3− ), oxalate (C 2 O 4 2− ), acetate (C 2 H 3 O 2 − , tartrate (C 4 H 4 O 6 2− ), and/or the ligand of ethylenediaminetetracetic acid ([EDTA] 4− ).

3. The stable rhodochrosite of claim 1 , wherein the organic acid comprises citric acid (C 6 H 8 O 7 ), oxalic acid (C 2 H 2 O 4 ), acetic acid (C 2 H 4 O 2 ), tartaric acid (C 4 H 6 O 6 ), and/or ethylenediaminetetraacetic acid (C 10 H 16 N 2 O 8 ).

4. The stable rhodochrosite of claim 1 , wherein the salt comprises mono-sodium phosphate (NaH 2 PO 4 ), di-sodium phosphate (Na 2 HPO 4 ), tri-sodium phosphate (Na 3 PO 4 ), tetra-sodium phosphate (Na 4 P 2 O 7 ), mono-sodium citrate (C 6 H 7 NaO 7 ), di-sodium citrate (C 6 H 6 Na 2 O 7 ), tri-sodium citrate (Na 3 C 6 H 5 O 7 ), di-sodium oxalate (Na 2 C 2 O 4 ), mono-potassium acetate (KCH 3 COO), mono-potassium tartrate (C 4 H 5 KO 6 ), and/or tri-potassium ethylenediaminetetraacetic acid (tri-potassium EDTA, C 10 H 13 K 3 N 2 O 8 ).

5. A method of producing stable rhodochrosite comprising manganese carbonate (MnCO 3 ), the method comprising:

providing a rhodochrosite comprising manganese carbonate (MnCO 3 );

treating the rhodochrosite by applying an aqueous treatment solution of phosphoric acid (H 3 PO 4 ), pyrophosphoric acid (H 4 P 2 O 7 ), an organic acid selected from the group consisting of citric acid (C 6 H 8 O 7 ), oxalic acid (C 2 H 2 O 4 ), acetic acid (C 2 H 4 O 2 ), tartaric acid (C 4 H 6 O 6 ), and/or ethylenediaminetetraacetic acid (C 10 H 16 N 2 O 8 ), or a salt of such acids, or a mixture thereof to the provided rhodochrosite to form a treated rhodochrosite; and

drying the treated rhodochrosite to produce stable rhodochrosite.

6. The method of claim 5 , wherein the provided rhodochrosite comprises a manganese carbonate (MnCO 3 ) precipitate and liquid and the application of the aqueous treatment solution comprises displacing the liquid contained in the rhodochrosite with an approximately equal amount of treatment solution.

7. The method of claim 5 , wherein the aqueous treatment solution is sprayed on the rhodochrosite.

8. The method of claim 5 , wherein the aqueous treatment solution is mixed with the rhodochrosite in a blender.

9. The method of claim 5 , wherein the aqueous treatment solution applied to the rhodochrosite comprises 0.3-3.0 grams of anions and/or ligands of the phosphoric acid (H 3 PO 4 ), pyrophosphoric acid (H 4 P 2 O 7 ), organic acids, or salts of such acids for each 1000 grams, on a dried basis, of rhodochrosite that is being treated.

10. The method of claim 9 , wherein the anion or ligand comprises phosphate (PO 4 3− ), pyrophosphate (P 2 O 7 4− ), citrate (C 6 H 5 O 7 3− ), oxalate (C 2 O 4 2− ), acetate (C 2 H 3 O 2 − ), tartrate (C 4 H 4 O 6 2− ), and/or the ligand of ethylenediaminetetracetic acid ([EDTA] 4− ).

11. The method of claim 5 , wherein the salt comprises mono-sodium phosphate (NaH 2 PO 4 ), di-sodium phosphate (Na 2 HPO 4 ), tri-sodium phosphate (Na 3 PO 4 ), tetra-sodium phosphate (Na 4 P 2 O 7 ), mono-sodium citrate (C 6 H 7 NaO 7 ), di-sodium citrate (C 6 H 6 Na 2 O 7 ), tri-sodium citrate (Na 3 C 6 H 5 O 7 ), di-sodium oxalate (Na 2 C 2 O 4 ), mono-potassium acetate (KCH 3 COO), mono-potassium tartrate (C 4 H 5 KO 6 ), and/or tri-potassium ethylenediaminetetraacetic acid (tri-potassium EDTA, C 10 H 13 K 3 N 2 O 8 ).

12. The method of claim 5 , wherein the provided rhodochrosite comprises a manganese carbonate (MnCO 3 ) precipitate obtained by mixing a solution comprising Mn with a solution containing carbonate from which a manganese carbonate (MnCO 3 ) precipitates and a reaction solution is formed.

13. The method of claim 12 , wherein the manganese carbonate (MnCO 3 ) precipitate has been substantially separated from the reaction solution but still contains residual reaction solution.

14. The method according to claim 13 , wherein the manganese carbonate (MnCO 3 ) precipitate has been washed at least once with water to dilute the residual reaction solution remaining in the manganese carbonate (MnCO 3 ) precipitate.

15. The method of claim 5 , wherein the treated rhodochrosite after drying contains at most 3% residual liquid.

16. The method of claim 5 , wherein the stable rhodochrosite comprises 0.03-0.3 wt % of an anion or ligand of the phosphoric acid (H 3 PO 4 ), organic acid, or salt of such acids.

17. A method of producing stable rhodochrosite comprising manganese carbonate (MnCO 3 ), the method comprising:

providing a rhodochrosite comprising manganese carbonate (MnCO 3 );

treating the rhodochrosite by applying an aqueous treatment solution of phosphoric acid (H 3 PO 4 ), pyrophosphoric acid (H 4 P 2 O 7 ), an organic acid, or a salt of such acids, or a mixture thereof to the provided rhodochrosite to form a treated rhodochrosite; and

drying the treated rhodochrosite to produce stable rhodochrosite,

wherein the stable rhodochrosite comprises 0.03-0.3 wt % of an anion or ligand of the phosphoric acid (H 3 PO 4 ), pyrophosphoric acid (H 4 P 2 O 7 ), organic acid, or salt of such acids.

18. The method of claim 17 , wherein the provided rhodochrosite comprises a manganese carbonate (MnCO 3 ) precipitate and liquid and the application of the aqueous treatment solution comprises displacing the liquid contained in the rhodochrosite with an approximately equal amount of treatment solution.

19. The method of claim 17 , wherein the aqueous treatment solution is sprayed on the rhodochrosite.

20. The method of claim 17 , wherein the provided rhodochrosite comprises a manganese carbonate (MnCO 3 ) precipitate obtained by mixing a solution comprising Mn with a solution containing carbonate from which a manganese carbonate (MnCO 3 ) precipitates and a reaction solution is formed.