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NICKEL LATERITES characteristics, classification and processing options

NICKEL LATERITES characteristics, classification and processing options. Charles Butt August 2007. NICKEL DEPOSITS: LATERITES AND SULPHIDES. CUBA. 22 o N. PHILIPPINES. INDONESIA. 22 o S. NEW CALEDONIA. AUSTRALIA. SULPHIDES. LATERITES. NICKEL LATERITE.

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NICKEL LATERITES characteristics, classification and processing options

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  1. NICKEL LATERITES characteristics, classification and processing options Charles Butt August 2007

  2. NICKEL DEPOSITS: LATERITES AND SULPHIDES CUBA 22oN PHILIPPINES INDONESIA 22oS NEW CALEDONIA AUSTRALIA SULPHIDES LATERITES

  3. NICKEL LATERITE • Regolith, derived from ultramafic rocks, that contains commercially exploitable reserves of nickel (and, commonly, cobalt) i.e., an economic term, implying high grades and/or tonnages of Ni-rich material • ultramafic rocks, >~2500ppm Ni Peridotite: 40-90% olivine + pyroxene Dunite: >90% olivine ophiolite, komatiite; layered intrusives (all ± serpentinized)

  4. NICKEL SUPPLY: LATERITES AND SULPHIDES

  5. CLASSIFICATION OF NICKEL LATERITES A: Hydrous Mg-Ni silicate deposits (~35% of total resource) Altered serpentines, népouite, “garnierite” in saprolite High grade: global mean 1.53% Ni Moderate to high relief; savanna, tropical rainforest B: Smectite silicate deposits (~15% of total resource) Clays (e.g., nontronite) in upper saprolite and pedolith Low grade: global mean 1.21% Ni Low relief; savanna, semi-arid C:Oxide deposits (~50% of total resource) Fe and minor Mn oxides, in upper saprolite and pedolith Low grade: global mean 1.06% Ni Most environments CRMB

  6. EAST PINARES Cuba Oxide Photo: Mick Elias

  7. GORO New Caledonia Oxide; some hydrous silicate CRMB

  8. CAWSE Western Australia Oxide CRMB

  9. OXIDE NICKEL LATERITE PROFILE: CAWSE Ni% Co % MgO% Fe % SiO % 2 0.08 0.04 1.0 7.6 70.8 CAWSE Duricrust 0.20 0.07 0.3 8.5 82.3 Mottled and plasmic clays 1.26 44.1 0.04 1.1 35.9 Mn oxides Silica Shear Ferruginous 0.46 0.15 0.08 18.1 72.3 saprolite Mn oxides Mg discontinuity 0.47 0.16 29.4 26.7 7.2 Saprolite Shear Magnesite 0.19 0.09 39.5 5.8 28.3 Saprock Bedrock 0.25 0.12 42.3 8.3 36.6 Serpentinized dunite CRBs021-01 CRMB

  10. PRINCIPAL NICKEL MINERALS OXIDE DEPOSITS CRMB

  11. PLATEAU New Caledonia Hydrous silicate; minor oxide CRMB

  12. PLATEAU New Caledonia Hydrous silicate CRMB

  13. CIRCE New Caledonia Hydrous silicate “garnierite” ore CRMB

  14. HYDROUS SILICATE (GARNIERITE) – OXIDE PROFILE Oxide

  15. PRINCIPALNICKEL MINERALS HYDROUS NI-MG SILICATES CRMB

  16. BULONG Western Australia Smectite silicate CRMB

  17. MURRIN MURRIN Western Australia Smectite silicate CRMB

  18. MURRIN MURRIN Smectite silicate Western Australia magnesite Photo: Martin Wells

  19. SMECTITE SILICATE PROFILE CRMB

  20. PRINCIPALNICKEL MINERALS SMECTITE DEPOSITS Minor goethite, asbolan CRMB

  21. PROCESSING OPTIONS FOR NICKEL LATERITES CRMB

  22. PROCESSING OPTIONS RELATIVE TO DEPOSIT TYPE Oxide (or smectite) Transition Hydrous silicate (after Elias 2001)

  23. ~77% of total production in 2000 33% or less of new capacity NICKEL LATERITE PROCESSING Smelting Ni: >2.0% Co: 0.04% Fe: 20% MgO: 25% Hydrous silicate ore (“garnierite”; serpentine) Too costly for smectite F E E D Upgrading e.g., tumbling of boulder ore P R O C E E S S Drying Reduction roast 1400 - >1600ºC; high energy cost Smelting Converting P R O D U C T SiO2/MgO <2 or >2.5 = ferronickel SiO2/MgO 1.8-2.2 = matte Fe-Ni or Ni matte 90% recovery CRMB

  24. NICKEL LATERITE PROCESSING Caron process Ni: 1.8% Co: 0.1% Fe: 25-40% MgO: <12.0% High grade oxide ore, some hydrous silicate; tolerates more Mg than HPAL. Too costly for smectite. F E E D Grinding, drying P R O C E E S S ~700ºC; high energy cost Reduction roast Leach ammoniacal CO3 Cobalt separation Complex pyrometallurgical - hydrometallurgical process; high energy cost with lower recoveries than smelting and PAL. No new plants anticipated Ni carbonate precipitation Calcining P R O D U C T Ni: 94% recovery Co: 90% recovery CRMB

  25. NICKEL LATERITE PROCESSING High pressure acid leaching Ni: 1.3% Co: 0.13% MgO: <5.0% Oxide or smectite ore, low Mg and Al to reduce acid consumption F E E D Upgrade oxide by screening to remove barren silica Ore preparation S P R O C E E S S 240-270ºC; lower energy cost cf Caron process Acid plant Leach H2SO4 High capital costs, with new plants having numerous teething problems in plant and process. Wash/neutralize Energy SX-EW or precipitate P R O D U C T Product options include sulphides: Murrin2, Halmahera hydroxide: Ravensthorpe, Vermelho carbonate: Cawse Ni: 94% recovery Co: 90% recovery CRMB

  26. Murrin Murrin

  27. NICKEL LATERITE PROCESSING Atmospheric leaching Ravensthorpe, Gag Island: oxide, serpentine saprolite (hydrous silicate) Sechol: oxide, saprolite Oxide ore (but, potentially, any ore type, including low grade hydrous silicate) F E E D Ore preparation S Enhanced high pressure acid leaching (EPAL); 80-105ºC P R O C E E S S Acid plant or excess from HPAL Agitate, heat and leach H2SO4 Sechol/Jaguar tested HCl/MgCl2 leach at 80-105ºC. Process could also yield MgO and magnetite concentrate as products. Trial discontinued Wash/neutralize Energy SX-EW or precipitate P R O D U C T Ni (Co) hydroxide ~80-90% recovery CRMB

  28. NICKEL LATERITE PROCESSING Heap leaching Caldag, Nornico - oxide; Murrin Murrin - smectite Potentially, any ore type, including low grade hydrous silicate and rejects F E E D Crush; upgrade by screening to remove barren silica Ore preparation S P R O C E E S S Acid plant or excess from HPAL Heap, irrigate for 12-18 months Neutralize using low grade saprolite ore Wash/neutralize Energy SX-EW or precipitate P R O D U C T Suitable for smaller deposits; low capex and opex Ni (Co) hydroxide ~80% recovery CRMB

  29. Çaldağ Heap Leach project, Turkey Istanbul * Çaldağ Izmir * 20 km 50 km 200 m From top of Heap 2 looking at Çaldağ mountain Demonstration precipitation plant European Nickel plc 2006

  30. PROCESSING OPTIONS FOR NICKEL LATERITES $US/lb Ni Source: Minara Resources, 2006 CRMB

  31. NICKEL LATERITE PROCESSING: Summary and conclusions 1: Nickel laterites form ~ 75% of known Ni resources 2: By 2010, over 50% of Ni will be derived from NiL 3: Three main ore types: oxide, hydrous silicate, smectite; all products of humid weathering, ± later modification 4: “Traditional” processing (smelting, Caron) is generally very energy intensive 5: HPAL plants use less energy but require high capital expenditure and are yet to be fully optimized; best suited to large deposits CRMB

  32. NICKEL LATERITE PROCESSING: Summary and conclusions (continued): 6: Acid leaching at lower temperatures and ambient pressures offer lower capital expenditure (but lower recovery). Suited for treating lower grade ore and small or remote deposits 7: Better mineralogical characterization is needed to optimize grade control, beneficiation and processing CRMB

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