Patent EA-005279-B1 (EA)
Title: Processing elemental sulfur-bearing materials using high temperature pressure leaching for sulfuric acid production and metal recovery
Inventor: MARSDEN JOHN O
IPC: C22B3/06
Filed: 2001-07-25
Abstract: 1. A treatment process comprising the steps of: pressure leaching said sulfur-bearing material at a temperature in the range of about 220 degree C to about 275 degree C in an oxygen-containing atmosphere in an agitated multiple-compartment pressure leaching vessel to form a product slurry comprising a sulfuric acid solution; separating at least a portion of said sulfuric acid solution from said product slurry to yield a residue; recovering at least one metal value from said residue. 2. The process of claim 1, wherein said elemental sulfur bearing material comprises a sulfur product stream from a pressure leaching operation carried out at a temperature in the range of about 140 degree C to about 180 degree C. 3. The process of claim 2 further comprising the step of adding a dispersant to said pressure leaching vessel during pressure leaching. 4. The process of claim 3 wherein said step of adding a dispersant to said pressure leaching vessel during pressure leaching comprises adding a sufficient amount of ground sand or mineral processing tailings. 5. The process of claim 4 wherein said step of recovering metal values from said residue comprises recovering at least one precious metal from said residue. 6. The process of claim 4 wherein said step of pressure leaching said sulfurbearing material comprises pressure leaching at temperatures above about 235 degree C. 7. The process of claim 4 wherein said step of pressure leaching said sulfurbearing material comprises pressure leaching at temperatures in the range of about 250 degree C. 8. A process for recovering metal values from the solid residue of a pressure leaching process carried out at a temperature in the range of about 140 degree C to about 180 degree C, the process comprising the steps of: comminuting the solid residue from the pressure leaching process carried out at a temperature in the range of about 140 degree C to about 180 degree C to produce a feed material; forming a feed slurry by combining said feed material with a sufficient amount of fluid medium; pressure leaching said feed slurry at a temperature in the range of about 220 degree C to about 275 degree C in an oxygen-containing atmosphere to yield a pressure leach product slurry comprising a sulfuric acid solution; reducing the temperature and pressure of said product slurry; separating at least a portion of said sulfuric acid solution from said product slurry to yield a solid residue; recovering at least one metal value from said solid residue. 9. The process of claim 8 wherein said step of recovering at least one metal value from said solid residue comprises recovering one or more precious metals contained in said residue. 10. The process of claim 8 wherein said step of reducing the temperature and pressure of said product slurry comprises flashing said product slurry. 11. The process of claim 8, said process further comprising the step of utilizing at least a portion of said sulfuric acid solution in connection with other processing operations. 12. The process of claim 8 wherein said step of pressure leaching said feed slurry is conducted at a temperature in the range in excess of about 235 degree C. 13. The process of claim 8 wherein said step of forming a feed slurry further comprises adding a dispersant. 14. The process of claim 13 wherein said step of forming a feed slurry further comprises adding a sufficient amount of ground sand or mineral processing tailings. 15. The process of claim 8 further comprising the step of adding a dispersant during pressure leaching. 16. The process of claim 15 wherein said step of adding a dispersant during pressure leaching comprises adding a sufficient amount of ground sand or mineral processing tailings. 17. A process for the production of sulfuric acid and recovery of precious metals from an elemental sulfur-bearing material comprising the steps of: pressure leaching said elemental sulfur-bearing material at a temperature in the range of about 220 degree C to about 275 degree C in an oxygen-containing atmosphere in an agitated multiple-compartment pressure leaching vessel to form a product slurry comprising a sulfuric acid solution; adding a dispersant during said pressure leaching step; d) separating at least a portion of said sulfuric acid solution from said product slurry to yield a solid residue; recovering at least one precious metal value from said solid residue. 18. The process of claim 17 wherein comprises providing a sulfur-containing product stream from a pressure leaching operation carried out at a temperature in the range of about 140 degree C to about 180 degree C. 19. The process of claim 18 wherein said step of adding a dispersant comprises adding a sufficient amount of ground sand or mineral processing tailings. 20. The process of claim 19 wherein said step of pressure leaching comprises pressure leaching at a temperature of about 235 degree C. 21. A process for recovering metal values from the solid residue of a pressure leaching process carried out at a temperature in the range of about 140 degree C to about 180 degree C, the process comprising the steps of: comminuting the solid residue from the pressure leaching process carried out at a temperature in the range of about 140 degree C to about 180 degree C to produce a feed material; forming a feed slurry by combining said feed material with a sufficient amount of fluid medium and by adding a sufficient amount of ground sand or mineral processing tailings; pressure leaching said feed slurry at a temperature in the range of about 220 degree C to about 275 degree C in an oxygen-containing atmosphere to yield a pressure leach product slurry comprising a sulfuric acid solution; reducing the temperature and pressure of said product slurry; separating at least a portion of said sulfuric acid solution from said product slurry to yield a solid residue; recovering at least one metal value from said solid residue. 22. A process for recovering metal values from the solid residue of a pressure leaching process carried out at a temperature in the range of about 140 degree C to about 180 degree C, the process comprising the steps of: comminuting the solid residue from the pressure leaching process carried out at a temperature in the range of about 140 degree C to about 180 degree C to produce a feed material; forming a feed slurry by combining said feed material with a sufficient amount of fluid medium; adding a sufficient amount of ground sand or mineral processing tailings; pressure leaching said feed slurry at a temperature in the range of about 220 degree C to about 275 degree C in an oxygen-containing atmosphere to yield a pressure leach product slurry comprising a sulfuric acid solution; adding a sufficient amount of ground sand or mineral processing tailings; reducing the temperature and pressure of said product slurry; separating at least a portion of said sulfuric acid solution from said product slurry to yield a solid residue; recovering at least one metal value from said solid residue.