Process for the dissolution of copper metal

1. A process for producing a copper-containing aqueous solution, comprising dissolving a copper mass in the presence of an oxidant in an aqueous leach liquor containing monoethanolamine and monoethanolammonium carbonate (HMEA) 2 CO 3 , and maintaining the pH of the aqueous leach liquor between 8 and 13, wherein said aqueous leach liquor is produced by partially carbonating the monoethanolamine, the aqueous leach liquor comprises about 30% and about 45% by weight of total monoethanolamine, and wherein the aqueous leach liquor dissolves between 100 grams and 130 grams of copper per liter of aqueous leach liquor in 48 hours or less.

2. The process according to claim 1 , wherein said oxidant is selected from the group consisting of air, oxygen, or mixture thereof.

3. A process according to claim 1 , wherein the process is carried out at a temperature of 25-100° C.

4. A process according to claim 1 , wherein the process is carried out at a temperature of 40-80° C.

5. A process according to claim 1 , wherein said temperature is 45-55° C.

6. The process according to claim 1 , wherein the step of dissolving comprises circulating the aqueous leach liquor through the copper mass with a circulation pump, wherein the copper mass is a three dimensional open network that is permeable to the leach liquor.

7. The process according to claim 6 , wherein said circulating is carried out at a rate of about 2 to about 10% of the volume of the leach solution per minute.

8. A process according to claim 1 , wherein the reaction is represented by the following equation:

Cu+3.5MEA+(1-x)CO 2 +0.5O 2 +xH 2 →Cu(MEA) 3.5 (CO 3 ) (1-x) (OH) 2x .

9. The process according to claim 1 , wherein said partial carbonating of said the monoethanolamine is according to the following equation:

3.5MEA+xCO 2 +H2O→(3.5−2x)MEA+(HMEA) 2x [CO 3 ],

where x is less than or equal to 1.0.

10. A process according to claim 1 , wherein partial carbonation is achieved using carbon dioxide.

11. A process according to claim 10 , wherein the carbon dioxide is present in an amount of about 0.5-30% by weight.

12. The process according to claim 1 , wherein the pH is 9 to 12.5.

13. The process according to claim 1 , wherein the pH is 9.5 to 12.5.

14. A process according to claim 1 , wherein ratio of copper surface area to volume of leach liquor is about 200:1.

15. A process according to claim 1 , wherein ratio of copper surface area to volume of leach liquor is about 10-20:1.

16. A process according to claim 1 , performed as a batch process.

17. A process according to claim 16 , wherein the average copper dissolution rate is about 2.5-40 g/l-hour.

18. A process according to claim 16 , wherein the average copper dissolution rate is about 8-18 g/l-hour.

19. A process according to claim 1 , performed as a continuous process.

20. The process according to claim 1 , wherein the carbon dioxide is added in an amount of about 0.5-5% by weight.

21. The process according to claim 1 , wherein the carbon dioxide is added in an amount of about 1-18% by weight.

22. A process for producing a copper-containing aqueous solution product, said process comprising:

providing in a packed tower a copper mass having a three dimensional open network permeable to an aqueous solution;

providing an aqueous leach liquor comprising water, monoethanolamine, and (HMEA) 2 CO 3 , wherein said aqueous leach liquor is produced by forming an aqueous composition comprising between 0.5% and 30% by weight of carbon dioxide and about 30% and about 45% by weight of monoethanolamine;

providing air, oxygen, or mixture thereof; and

contacting the aqueous leach liquor with the air, oxygen, or mixture thereof and with the copper mass, thereby causing dissolution of a portion of the copper mass and forming the copper-containing aqueous solution product, wherein the aqueous leach liquor pH is between 8 and 13 and the temperature is between 25° C. and 100° C., and wherein the aqueous leach liquor dissolves between 100 grams and 130 grams of copper per liter of aqueous leach liquor in 48 hours or less.

23. The process of claim 22 , wherein the temperature of the leach liquor is maintained at a temperature between about 40° C. and about 80° C. wherein the leach liquor comprises between of monoethanolamine and between about 1% and 18% by weight of carbon dioxide, and wherein the aqueous leach liquor dissolves between 100 grams and 130 grams of copper per liter of aqueous leach liquor in 12 hours or less.

24. The process of claim 22 , wherein the leach liquor comprises between about 32% and about 40% by weight of monoethanolamine and between about 0.5% and about 5% by weight of carbon dioxide.

25. The process of claim 22 , wherein the pH of the aqueous leach liquor is between 9 and 12.5.

26. The process of claim 23 , wherein the pH of the leach liquor is between 9.5 and 12.5.

27. The process of claim 22 , wherein the pH of the leach liquor is between 10.2 and 12.7.

28. The process of claim 22 , wherein the pH of the leach liquor is between 11.7 and 12.2.

29. The process of claim 22 , wherein the pH of the leach liquor is maintained at about 11.9.

30. The process of claim 23 , wherein the temperature is between 45° C. and 65° C. and wherein the aqueous leach liquor dissolves between 100 grams and 130 grams of copper per liter of aqueous leach liquor in 8 hours or less.

31. The process of claim 22 , wherein the leach liquor is free of ammonium hydroxide and alkali metal hydroxides.

32. The process of claim 22 , wherein the leach liquor is free of polyamines.

33. The process of claim 23 , wherein the leach liquor is free of alcohols and carboxylic acids.

34. The process of claim 22 , wherein the step of contacting the leach liquor with the copper mass comprises circulating the aqueous leach liquor through the copper mass with a circulation pump, wherein the copper mass is immersed in the leach liquor.

35. The process of claim 34 , wherein said circulating comprises withdrawing aqueous leach liquor from a location below the copper mass and reintroducing the withdrawn aqueous leach liquor at a location above the copper mass.

36. The process of claim 34 , wherein said circulating is at a rate of about 0.02 to 0.1 of the aqueous leach liquor volume per minute.

37. The process of claim 22 , further comprising contacting the aqueous leach liquor with a heat exchanger and removing heat from the aqueous leach liquor.

38. A process for producing a copper-containing aqueous solution comprising:

providing an aqueous leach liquor comprising water, monoethanolamine, and carbon dioxide, wherein the temperature of the leach liquor is maintained at a temperature between 25° C. and 100° C. and the pH of the leach liquor is between 9 and 12.5;

providing oxygen; and

contacting the leach liquor and the oxygen with copper metal, thereby causing dissolution of at least a portion of the copper metal and forming the copper-containing aqueous solution.

39. The process of claim 38 , wherein gas comprising molecular oxygen is a mixture of oxygen and air.

40. The process of claim 38 , wherein gas comprising molecular oxygen further comprises carbon dioxide.

41. The process of claim 33 , wherein the contacting is done in a packed tower having a volume, wherein the step of adding oxygen comprises adding air at a rate of between about 12,000 to about 24,000 standard cubic feet per hour per 11,500 gallons of volume.

42. The process of claim 41 , wherein wherein leach liquor is circulated from the bottom of the packed tower to the top of the packed tower.

43. The process of claim 38 , wherein the rate of dissolution of copper metal is between about 5 and about 36 grams of copper metal dissolved per liter of leach liquor per hour.

44. The process of claim 38 , wherein the rate of dissolution of copper metal is at least 17 grams of copper metal dissolved per liter of leach liquor per hour.