Process for leaching metal sulfides with reagents having thiocarbonyl functional groups

1. A method of recovering at least one base metal ion from a material comprising at least one base metal sulfide, the method comprising:

contacting the material with an acidic solution comprising halide ions and a reagent having a thiocarbonyl functional group, wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 100 mM, to produce a pregnant solution comprising the at least one base metal ion; and

recovering the at least one base metal ion from the pregnant solution.

2. The method of claim 1 , wherein the acidic solution further comprises at least one oxidizing agent.

3. The method of claim 2 , wherein the at least one oxidizing agent comprises a source of ferric ions.

4. The method of claim 3 , wherein the source of ferric ions comprises ferric sulfate.

5. The method of claim 3 , wherein the source of ferric ions comprises ferric ions generated at least in part by bacteria.

6. The method of claim 2 , wherein the oxidizing agent comprises an oxidation-reduction potential of less than 900 mV.

7. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is sufficient to increase the rate of the at least one base metal ion recovery relative to an acidic solution that does not comprise the reagent.

8. The method of claim 1 , wherein the acidic solution comprises a ferric sulfate solution.

9. The method of claim 1 wherein the acidic solution comprises a sulfate solution.

10. The method of claim 1 , wherein the acidic solution comprises a ferric solution.

11. The method of claim 1 , wherein the acidic solution comprises a ferric media.

12. The method of claim 1 , wherein the acidic solution is replaced with a ferrous sulfate solution.

13. The method of claim 12 , wherein the ferrous sulfate solution comprises a source of F 2+ ions that are actively oxidized by F 3+ by bacteria.

14. The method of claim 1 , wherein the thiocarbonyl functional group of the reagent has a sulfur that bears a partial negative charge, bears a negative electrostatic potential surface, and has an empty π*-antibonding orbital as its lowest unoccupied molecular orbital.

15. The method of claim 1 , wherein the reagent is thiourea (Tu).

16. The method of claim 1 , wherein the reagent is thioacetamide (TA).

17. The method of claim 1 , wherein the reagent is sodium dimethyldithiocarbamate (SDDC).

18. The method of claim 1 , wherein the reagent is ethylene trithiocarbonate (ETC).

19. The method of claim 1 , wherein the reagent is thiosemicarbazide (TSCA).

20. The method of claim 1 , wherein the reagent is not thiourea.

21. The method of claim 1 , wherein the reagent is N-N′ substituted thioureas; 2,5-Dithiobimea; Dithiobiuret; Thiosemicarbazide purum; Thiosemicarbazide; Thioacetamide; 2-Methyl-3-thiosemicarbazide; 4-Methyl-3-thiosemicarbazide; Vinylene trithiocarbonate purum; Vinylene trithiocarbonate; 2-Cyanothioacetamide; Ethylene trithiocarbonate; Potassium ethyl xanthogenate; Dimethylthiocarbamoyl chloride; Dimethyldithiocarbamate; Dimethyl trithiocarbonate; N,N-Dimethylthioformamide; 4,4-Dimethyl-3-thiosemicarbazide; 4-Ethyl-3-thiosemicarbazide; O-Isopropylxanthic acid; Ethyl thiooxamate; Ethyl dithioacetate; Pyrazine-2-thiocarboxamide; Diethylthiocarbamoyl chloride; Diethyldithiocarbamate; Tetramethylthiuram monosulfide; Tetramethylthiuram disulfide; Pentafluorophenyl chlorothionoformate; 4-Fluorophenyl chlorothionoformate; O-Phenyl chlorothionoformate; Phenyl chlorodithioformate; 3,4-Difluorothiobenzamide; 2-Bromothiobenzamide; 3-Bromothiobenzamide; 4-Bromothiobenzamide; 4-Chlorothiobenzamide; 4-Fluorothiobenzamide; Thiobenzoic acid; Thiobenzamide; 4-Phenylthiosemicarbazide; O-(p-Tolyl) chlorothionoformate; 4-Bromo-2-methylthiobenzamide; 3-Methoxythiobenzamide; 4-Methoxythiobenzamide; 4-Methylbenzenethioamide; Thioacetanilide; Salicylaldehyde thiosemicarbazone; Indole-3-thiocarboxamide; S-(Thiobenzoyl)thioglycolic acid; 3-(Acetoxy)thiobenzamide; 4-(Acetoxy)thiobenzamide; Methyl N′-[(e)-(4-chlorophenyl)methylidene]hydrazonothiocarbamate; 3-Ethoxythiobenzamide; 4-Ethylbenzene-1-thiocarboxamide; Tert-butyl 3-[(methylsulfonyl)oxy]-1-azetanecarboxylate; Diethyldithiocarbamic acid; 2-(Phenylcarbonothioylthio)propanoic acid; 2-Hydroxybenzaldehyde; N-ethylthiosemicarbazone; (1R,4R)-1,7,7-Trimethylbicyclo[2.2.1]heptane-2-thione; Tetraethylthiuram disulfide; 4′-Hydroxybiphenyl-4-thiocarboxamide; 4-Biphenylthioamide; Dithizone; 4′-Methylbiphenyl-4-thiocarboxamide; Tetraisopropylthiuram disulfide; Anthracene-9-thiocarboxamide; Phenanthrene-9-thiocarboxamide; Sodium dibenzyldithiocarbamate; 4,4′-Bis(dimethylamino)thiobenzophenone; or any combination thereof.

22. The method of claim 1 , wherein the material is an ore.

23. The method of claim 1 , wherein the material is a concentrate of the at least one base metal sulfide.

24. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 60 mM.

25. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 30 mM.

26. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 20 mM.

27. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 10 mM.

28. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 5 mM.

29. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 2.0 mM.

30. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 1.0 mM.

31. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 0.001 mM to 0.2 mM.

32. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 2 mM to 100 mM.

33. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 2 mM to 60 mM.

34. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 2 mM to 30 mM.

35. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 2 mM to 20 mM.

36. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 2 mM to 10 mM.

37. The method of claim 1 , wherein the concentration of the reagent in the acidic solution is in the range of 2 mM to 5 mM.

38. The method of claim 1 , wherein the at least one base metal comprises copper and the at least one base metal sulfide comprises chalcopyrite.

39. The method of claim 1 , wherein the at least one base metal comprises copper and the at least one base metal sulfide comprises covellite.

40. The method of claim 1 , wherein the at least one base metal comprises copper and the at least one base metal sulfide comprises a copper sulfide of the formula Cu x S y wherein the x:y ratio is between 1 and 2.

41. The method of claim 40 , wherein the copper sulfide comprises chalcocite.

42. The method of claim 40 , wherein the copper sulfide comprises djurleite.

43. The method of claim 40 , wherein the copper sulfide comprises digenite.

44. The method of claim 1 , wherein the at least one base metal comprises copper and the at least one base metal sulfide comprises bornite.

45. The method of claim 1 , wherein the at least one base metal comprises copper and the at least one base metal sulfide comprises enargite.

46. The method of claim 1 , wherein the at least one base metal comprises cadmium and the at least one base metal sulfide comprises greenockite.

47. The method of claim 1 , wherein the at least one base metal comprises nickel and the at least one base metal sulfide comprises pentlandite.

48. The method of claim 1 , wherein the at least one base metal comprises nickel and the at least one base metal sulfide comprises violarite.

49. The method of claim 1 , wherein the method comprises a leach.

50. The method of claim 49 , wherein the leach comprises a percolation leach.

51. The method of claim 49 , wherein the leach comprises a heap leach.

52. The method of claim 49 , wherein the leach comprises a vat leach.

53. The method of claim 49 , wherein the leach comprises a tank leach.

54. The method of claim 49 , wherein the leach comprises a column leach.

55. The method of claim 1 , wherein the leach comprises a temperature between 0° C. and 80° C.

56. The method of claim 1 , wherein recovering the at least one metal from the pregnant solution comprises solvent extraction and electrowinning.

57. The method of claim 1 , further comprising maintaining the operating potential of the acidic solution above 500 mV vs Ag/AgCl.

58. The method of claim 1 , wherein the reagent does not complex/precipitate with the base metal ions.

59. The method of claim 1 , wherein the halide ions comprise chloride ions.

60. The method of claim 59 , wherein the concentration of the chloride ions in the acidic solution is in the range of about 1 g/L to about 200 g/L.

61. The method of claim 59 , wherein the concentration of the chloride ions in the acidic solution is in the range of about 1 g/L to about 60 g/L.

62. The method of claim 59 , wherein the concentration of the chloride ions in the acidic solution is in the range of about 1 g/L to about 20 g/L.

63. The method of claim 1 , wherein the halide ions comprise iodide ions.

64. The method of claim 63 , wherein the concentration of the iodide ions in the acidic solution is in the range of about 1 ppm to about 300 ppm.

65. The method of claim 63 , wherein the concentration of the iodide ions in the acidic solution is in the range of about 1 ppm to about 100 ppm.

66. The method of claim 63 , wherein the concentration of the iodide ions in the acidic solution is in the range of about 1 ppm to about 10 ppm.

67. The method of claim 1 , wherein the halide ions comprise bromide ions.

68. The method of claim 67 , wherein the concentration of the bromide ions in the acidic solution is in the range of about 1 g/L to about 30 g/L.

69. The method of claim 67 , wherein the concentration of the bromide ions in the acidic solution is in the range of about 1 g/L to about 20 g/L.

70. The method of claim 67 , wherein the concentration of the bromide ions in the acidic solution is in the range of about 1 g/L to about 10 g/L.

71. The method of claim 1 , wherein the reagent is ethylene thiourea (ETu).