1 / 34

Elution behaviour of metals from carbon SAIMM 2009

Elution behaviour of metals from carbon SAIMM 2009. M Jeffrey R Pleysier K Bunney. Background. National Pollution Inventory reporting (NPI) 93 reportable substances Objectives Help industry and government with environmental planning and management

issac
Download Presentation

Elution behaviour of metals from carbon SAIMM 2009

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Elution behaviour of metals from carbon SAIMM 2009 M Jeffrey R Pleysier K Bunney

  2. Background • National Pollution Inventory reporting (NPI) • 93 reportable substances • Objectives • Help industry and government with environmental planning and management • Provide communities with information on emissions • Promote waste minimisation, cleaner production and efficiency • Gold mines • Identified as major emitter of Hg • Not amalgamations but as ppm levels in cyanide leach liquors. CSIRO. Elution behaviour of metals from carbon 2

  3. Project Objectives - general • ID toxic trace elements in CIP streams • Deportment • Understand of the dissolution of toxic trace elements. (cyanide) • Potential to avoid or sequester in benign form. • Adsorption/elution characteristic • Hg, Ni, Cu, Sr, Cd, As,Pb, Si,Se, Sb, Te, Cr, ……..(19) CSIRO. Elution behaviour of metals from carbon 3

  4. Project Objectives - specific • Hg speciation ( carbon) • Mine site - Hg only partly elutes •  EW and smelt •  regen gases • Manage Hg in one concentrated stream • Elution Column – construct , description (better stripping of Hg) CSIRO. Elution behaviour of metals from carbon 4

  5. Laboratory Elution Column CSIRO. Elution behaviour of metals from carbon 5

  6. Laboratory Elution Column • Pump • Altex model 110A (PD piston type) • 0.1 – 10 mL/min • 0 – 25,000 kPa (4000 psi) CSIRO. Elution behaviour of metals from carbon 6

  7. Laboratory Elution Column • Pump • Gauges (2) • 0 – 1500 kPa (0-230 psi) CSIRO. Elution behaviour of metals from carbon 7

  8. Laboratory Elution Column • Pump • Gauges • PRV (2) • 70 – 1500 kPa adjustable • (10 – 225 psi) CSIRO. Elution behaviour of metals from carbon 8

  9. Laboratory Elution Column • Pump • Gauges • PRV • Column • ØID 25 x 600 mm SS swagelok fittings • 100 g carbon capacity • 150 mL void volume. • Screens top and bottom (300μm) CSIRO. Elution behaviour of metals from carbon 9

  10. Laboratory Elution Column • Pump • Gauges • PRV • Column • Heating • Electrical heating tape/insulated • T/C (type k) • PID controller (Eurotherm CE 375) • Pre heater coil for eluant. CSIRO. Elution behaviour of metals from carbon 10

  11. Laboratory Elution Column • Pump • Gauges • PRV • Column • Heating • Cooling • SS coil in water bucket CSIRO. Elution behaviour of metals from carbon 11

  12. Laboratory Elution Column • Pump • Gauges • PRV • Column • Heating • Outlet • 3 way • - to gauge • - prv • - needle control valve CSIRO. Elution behaviour of metals from carbon 12

  13. Commissioning • Samples • Local mine site • C1 (Au 909 g/t Hg 187 g/t) • C1 aw (Au 1140 g/t Hg 229 g/t) • C2 aw (Au 355 g/t Hg 92 g/t ) • Commissioning • AARL • (2% NaCN + 2% NaOH) • 130OC • Pressure 200 kpa • 30 min bake • 20 BV DI CSIRO. Elution behaviour of metals from carbon 13

  14. Commissioning -profiles • Pressure • 200 kpa gave poor flow control • 700 kpa gave better flow and temp control • Profile similar-not effected by pressure CSIRO. Elution behaviour of metals from carbon 14

  15. Commissioning -profiles • Pressure • Profiles similar • Hg eluted sl faster • Recovery sl lower • Earlier than gold • Typical plant recovery 50-60% CSIRO. Elution behaviour of metals from carbon 15

  16. Plant sample –Au profiles • Samples • 3 loaded carbon samples from local minesite • Good profiles and good recoveries for gold • Results similar to plant data. CSIRO. Elution behaviour of metals from carbon 16

  17. Plant sample – Hg profiles • Samples • As previous • Hg recovery only 57% • Lower if not acid washed 41%. • Mechanism of improvement yet to be determined. CSIRO. Elution behaviour of metals from carbon 17

  18. Vary temp – Au profiles • Effect of temp • 130oC = 93% Au • 160oC = 97% Au • Higher temp • Faster elution • Higher [Au]s • Higher recovery. CSIRO. Elution behaviour of metals from carbon 18

  19. Vary temp – Hg profiles • Effect of temp • 130oC = 57% Hg • 160oC = 40% Hg • Higher temp = • LESS mercury. • Higher temp decomposes NaCN ? CSIRO. Elution behaviour of metals from carbon 19

  20. Vary cyanide – Au profiles • Effect of cyanide • Increasing [NaCN] • Increases rate Au • Increases recovery CSIRO. Elution behaviour of metals from carbon 20

  21. Vary cyanide – Hg profiles • Effect of cyanide • Increasing [NaCN] • Increases rate Hg • Increases recovery • But still only 61% • Potential to leave Hg on carbon CSIRO. Elution behaviour of metals from carbon 21

  22. Zadra – Au profiles • Zadra • Maintains [CN] • Slower rate Au * * soak period added to determine impact on Hg elution CSIRO. Elution behaviour of metals from carbon 22

  23. Zadra – Hg profiles • Zadra • Maintains [CN] • Similar rate Hg • Improved recovery • 76% Hg recovery CSIRO. Elution behaviour of metals from carbon 23

  24. Zadra – Au at 110oC • Zadra • Maintains [CN] • Much slower rate • Very poor recovery • Temp important for Au CSIRO. Elution behaviour of metals from carbon 24

  25. Zadra – Hg at 110oC • Zadra • Maintains [CN] • Rapid elution • Recovery 87% CSIRO. Elution behaviour of metals from carbon 25

  26. Data Split elution • Gold Mercury • high temp low temp • low [CN] high [CN] • Mutually exclusive conditions  split elution? • Zadra at 90oC + 130oC AARL CSIRO. Elution behaviour of metals from carbon 26

  27. Split • Conditions • Zadra at 90oC • 2% NaOH • 2% NaCN • 1500 mL • AARL at 130oC • 30 min soak • DI elution 1000 mL CSIRO. Elution behaviour of metals from carbon 27

  28. Split elution results • Mercury • 98% recovery in 10BV at 90oC • Eluate… high Hg, low Au • Hg recovery via S ppt etc • Gold • 10-15% Au into Hg eluate • Further refinements possible (lower temp further???) • Gold recycle recovery? CSIRO. Elution behaviour of metals from carbon 28

  29. Summary • Recovery of Hg into one stream possible. (ie removal from carbon/regen circuit desirable  solution) • Elute/separate Hg/Au with one set of elution conditions not possible, • But split or sequential elutions works well • Further optimisation/recovery possible CSIRO. Elution behaviour of metals from carbon 29

  30. Further work / objectives • ID other toxic trace elements in CIP streams • Hg started, As, Se, Cd, Sb, Te, Pb, Cr, Ni, organics ??? • Deportment • What accumulate where? • Potential to avoid or sequester in benign form. • Adsorption/elution characteristic • Effect of acid washing? • Impact on silver • In progress. CSIRO. Elution behaviour of metals from carbon 30

  31. Contact Us Phone: 1300 363 400 or +61 3 9545 2176 Email: enquiries@csiro.au Web: www.csiro.au Thank you Minerals Ron Pleysier Project Scientist Phone: 08 9334 8923 Email: ron.pleysier@csiro.au Web: www.csiro.au/group

  32. Split elution - Ag • Silver • Elutes with Hg at low temp in CN • Residual with gold CSIRO. Elution behaviour of metals from carbon

  33. Split elution – reverse method • Silver • Partially elutes with Au at high temp low CN • But needs CN to elute bulk • Best conditions for silver elution 130oC with 2%NaCN and NaOH CSIRO. Elution behaviour of metals from carbon

  34. Hg Elutions - updates • 10M HNO3 will strip Hg from carbon on the bench overnight. • NaCN strips (atmospheric) at 40, 60, 75, 90oC CSIRO. Elution behaviour of metals from carbon 34

More Related