Presentation is loading. Please wait.

Presentation is loading. Please wait.

characteristics, classification and processing options

Similar presentations


Presentation on theme: "characteristics, classification and processing options"— Presentation transcript:

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

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

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: % olivine + pyroxene Dunite: >90% olivine ophiolite, komatiite; layered intrusives (all ± serpentinized)

Yes

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 Oxide; some hydrous silicate
GORO New Caledonia Oxide; some hydrous silicate CRMB

8 CAWSE Western Australia Oxide CRMB

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

15 PRINCIPAL NICKEL 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 PRINCIPAL NICKEL MINERALS
SMECTITE DEPOSITS Minor goethite, asbolan CRMB

21 PROCESSING OPTIONS FOR NICKEL LATERITES
ORE PRODUCT COMMENT Smelting 1859, New Caledonia Hydrous silicate Ferro-nickel matte Energy intensive; (smelting ~1600ºC) Caron process Reduction & ammoniacal leach 1944, Cuba Oxide; hydrous silicate (Mg <4%) Ni oxide; Ni briquettes Energy intensive (reduction ~700ºC) low Co recovery High pressure acid leach (HPAL) 1959, Moa Bay, Cuba Oxide; smectite (Mg <4%) Ni briquettes; electronickel; oxide, sulphide, carbonate Less energy intensive. Plant & process problems Enhanced high pressure acid leach (EPAL) Ni-Co hydroxide Atmospheric leach after HPAL Acid heap leach H2SO4 Atmospheric leach H2SO4 HCl/MgCl2 Oxide; smectite hydrous silicate Lower capital cost; Lower recoveries CRMB

22 PROCESSING OPTIONS RELATIVE TO DEPOSIT TYPE
Oxide (or smectite) Transition Hydrous silicate Could process smectites by smelting but too costly (after Elias 2001)

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

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

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

26 Murrin Murrin

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

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

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

30 PROCESSING OPTIONS FOR NICKEL LATERITES
$US/lb Ni HPAL Atmospheric leach Heap leach Capital expenditure $17-22 $13-16 $8-12 Operating expenditure $2.50 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


Download ppt "characteristics, classification and processing options"

Similar presentations


Ads by Google