jean clement boyeme zogo, university of johannesburg
TRANSCRIPT
INTRODUCTION
• Manganore Iron Formation is
slumped into sinkhole structures
of the Campbellrand Subgroup
and occurs exclusively on the
Maremane Dome.
• Maremane Dome is an open
domal structure located between
Postmasburg in the south and
Kathu in the north, in the Northern
Cape Province of South Africa.
• Manganore Iron Formation is
Eroded in the centre of the
Maremane Dome.
IRON ORE BENEFICIATION AFRICA
INTRODUCTION • Manganore Iron Formation hosts bulk of high-
grade deposits of South Africa
• High-grade iron ores are produced at Sishen,
Khumani, Beeshoek and Kolomela (Sishen
South)
• Almost 84% of iron ore produced in South Africa;
• Presence of low grade material 34-36 wt. % Fe
• Hematite and quartz with specific gravity 5.2gcm-3
and 2.7 g.cm-3
• Beeshoek and Khumani mines are operated by
Assmang Ltd;
• 3 types of ore products: Lumpy – Fines – DR
lump;
• Materials containing less than 60 wt. % Fe are
discarded;
IRON ORE BENEFICIATION AFRICA
STRATIGRAPHY AND OCCURRENCE OF LOW-GRADE IRON ORES
Oxidized and partly ferruginized MIF occurs closely associated with high-grade iron ore; 1. Banded MIF type occurs below high-grade laminated iron ore; 2. Breccia textured type MIF occurs above a chert breccia unit, Wolhaarkop Breccia; Both MIF types has been evaluated from drill cores -(34 -102m thick) and hand samples .
IRON ORE BENEFICIATION AFRICA
Unconformity
Gamagara Formation
Campbellrand Subgroup
Palin Shale
Dolomite
Wolhaarkop Chert Breccia
BIF Breccia
Iron Ore
Doornfontein Conglomerate
Sishen Shale
Marthaspoort quartzites
Manganore Iron
Formation
BACKGROUND AND MOTIVATIONS: PROJECTS GRIQUALAND WEST BASIN
• Hotazel (This Study)
• Sishen B Grade (Koumba)
• Sep 1B (Koumba)
• Shishen Concentrate (K.)
• Pipeline (Koumba)
• Aquila
• Beeshoek Village
(Assmang)
TRANSVAAL BASIN/ BUSHVELD
• Gulukwane iron project
• Malemane
• Turquoise Moon
• Phoenix (Thabazimbi)
• Zandrivierspoort
SAMPLE COLLECTION • Drilled cores; open pits,
waste damps IRON ORE BENEFICIATION AFRICA
Modified after the Council of Geoscience
PHYSICAL CHARACTERIZATION: Texture & Mineralogy Banded MIF • Randomly alternating chert and hematite bands (<mm to 1cm) • Parallel, wavy, meandering, • Silica bands: chert or red jasper • Iron rich bands: laminated hematite; • Crosscut by fissures and micro-faults • Secondary mineralization • Mineralogy: Hematite/Specularite, Quartz, Apatite,…
IRON ORE BENEFICIATION AFRICA
Massive Iron Ore
Hematite Lutite Brecia Ore
Hematite Greenalite lutite
Thinly Laminate Ore
Thickly Laminate Ore
BIF/Breccia BIF
BIF Shale
Carbonaceous shale
PHYSICAL CHARACTERIZATION: Texture & Mineralogy
IRON ORE BENEFICIATION AFRICA
Massive Iron Ore
Hematite Lutite Brecia Ore
Hematite Greenalite lutite
Thinly Laminate Ore
Thickly Laminate Ore
BIF/Breccia BIF
BIF Shale
Carbonaceous shale
Breccia textured MIF • Lies immediately below the banded MIF • Formed in response to the collapse of banded MIF and high-grade
iron ore • Mixture of angular to subrounded fragments of BIF, chert, jasper, old
hematite ore,… • Clasts size: mm to cm • Pore spaces filled by crystalline hematite or specularite - clast or
matrix supported • Mineralogy: Hematite/specularite, Martite, Quartz, minor magnetite
PHYSICAL CHARACTERIZATION: Grain Size Analysis
IRON ORE BENEFICIATION AFRICA
Sieve Size (µm)
Average Chemical Composi6on of the Breccia-‐textured MIF size frac6ons SiO2 TiO2 Al2O3 Fe2O3 Mn3O4 MgO CaO K2O P2O5 S
(wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %) (wt. %)
+4000 29.4 0.01 0.24 67.3 0.02 0.10 0.12 0.00 0.10 0.19
-‐4000+2000 27.7 0.03 0.41 67.8 0.02 0.17 0.18 0.04 0.10 0.04
-‐2000+1000 28.2 0.01 0.27 68.7 0.02 0.11 0.13 0.00 0.12 0.11
-‐1000+600 24.9 0.04 0.60 71.6 0.04 0.16 0.17 0.08 0.11 0.01
-‐600+425 21.7 0.05 0.71 76.8 0.07 0.06 0.10 0.10 0.13 0.11
-‐425+212 24.3 0.03 0.68 71.6 0.07 0.15 0.17 0.08 0.13 0.05
-‐212 28.8 0.02 0.35 70.0 0.07 0.01 0.06 0.01 0.13 0.11
Average Chemical Composi6on of the Banded MIF size frac6ons +4000 42.7 0.02 0.29 51.9 0.01 0.12 0.15 0.00 0.11 0.08
-‐4000+2000 41.9 0.01 0.24 54.7 0.01 0.12 0.14 0.00 0.10 0.07
-‐2000+1000 44.2 0.01 0.12 52.5 0.02 0.09 0.10 0.01 0.06 0.05
-‐1000+600 48.5 0.01 0.12 48.1 0.03 0.10 0.11 0.00 0.06 0.11
-‐600+425 47.1 0.02 0.30 49.7 0.05 0.09 0.13 0.01 0.12 0.15
-‐425+212 42.3 0.02 0.43 53.1 0.07 0.18 0.18 0.01 0.11 0.16
-‐212 43.5 0.01 0.23 54.0 0.08 0.24 0.23 0.01 0.05 0.12
• In Breccia MIF: 67.3 to 76.8 wt. % Fe2O3 - (Si : 21.7 – 29.4 wt. %)
• In Banded MIF: 48.1 to 54.7 wt. % Fe2O3 – (Si: 41.9 – 48.5 wt. %)
• Significant iron enrichment up to 76.8 wt.% Fe2O3 in breccia textured
MIF for [-600+425µm]
• Texture important parameter for the liberation of ore mineral
GRAVITY SEPARATION: METHODOLOGY
IRON ORE BENEFICIATION AFRICA
Gravity Separation: MDS Mintek (mineral density
separator)
• PLC controlled air-pulsed batch jigging
• Separates according to mineral specific gravity
• Cylindrical Chamber: Clamped rings connected to
a water chamber ( Diam.: 385mm; H: 50mm);
• Pulsations: provided by air valves with PLC
controlling the frequency and the upstroke, holding
and release times;
• Input and output pressures: 200kPa/m and 14kPa/
mm;
• Valve Control Pressure: 400kPa/m
• Water flow: 1000l/h
• Residence time: 30 minutes
• Water: first turn to maximum then to low flow
• Sample Collection using a tray
• One layer = ring content
GRAVITY SEPARATION: RESULTS
IRON ORE BENEFICIATION AFRICA
(1) Breccia Textured MIF Average Layer SG Determina6ons
Layer Dry Mass Mass Cum. Mass M1 M2 M3 M5 Ave. SG Cum. SG SI
No g % % g g g g g.cm-‐3 g.cm-‐3 BoYom 1 4792.2 17.0 17.0 -‐29.8 1.4 2465.2 1902.4 4.63 4.63 0.67
2 4269.7 15.2 32.2 -‐29.0 3.2 2132.0 1608.0 4.33 4.49 0.37 3 4176.2 14.8 47.0 -‐29.6 2.0 2121.0 1583.0 4.18 4.39 0.22 4 3396.4 12.1 59.0 -‐29.8 2.6 1729.0 1268.0 4.03 4.31 0.07 5 3690.2 13.1 72.1 -‐29.4 2.4 1932.0 1406.0 3.90 4.23 0.06 6 3976.2 14.1 86.2 -‐29.2 2.4 2019.0 1438.0 3.67 4.13 0.29 7 2795.6 9.9 96.2 -‐29.4 2.8 1440.4 965.0 3.24 4.01 0.72
Top 8 1079.3 3.8 100.0 -‐29.2 3.0 510.8 308.2 2.98 3.96 0.98 Total 28175.8 100.0 3.96 0.38
(2) Banded MIF Average Layer SG Determina6ons
Layer Dry Mass Mass Cum. Mass M1 M2 M3 M5 Ave. SG Cum. SG SI
No g % % g g g g g/cc g/cc BoYom 1 4217.1 18.9 18.9 -‐28.8 3.0 2171.2 1624.4 4.21 4.21 0.72
2 3701.6 16.6 35.6 -‐28.2 4.0 1908.0 1375.8 3.81 4.01 0.31 3 3594.5 16.1 51.7 -‐28.2 3.8 1774.2 1256.0 3.64 3.89 0.15 4 3406.5 15.3 67.0 -‐27.6 4.8 1753.2 1212.4 3.44 3.78 0.05 5 2813.6 12.6 79.7 -‐29.0 2.8 1435.2 959.0 3.22 3.68 0.27 6 2990.7 13.4 93.1 -‐28.8 3.4 1495.2 956.8 2.95 3.55 0.55
Top 7 1537.7 6.9 100.0 -‐28.8 3.6 778.8 477.4 2.88 3.49 0.61 Total 22261.7 100.0 3.49 0.37
M1= Mass of basket in hair; M2= Mass of “water on basket” in air; M3= Sample in air (+ “Water on basket”); M4= Sample in air M3-M2; M5= sample in Water; SG = Specific gravity (= (M4)/[M4-(M5-M1)]
GRAVITY SEPARATION: RESULTS
IRON ORE BENEFICIATION AFRICA
(1) Breccia Textured MIF Average Layer SG Determina6ons
Layer Dry Mass Mass Cum. Mass M1 M2 M3 M5 Ave. SG Cum. SG SI
No g % % g g g g g.cm-‐3 g.cm-‐3 BoYom 1 4792.2 17.0 17.0 -‐29.8 1.4 2465.2 1902.4 4.63 4.63 0.67
2 4269.7 15.2 32.2 -‐29.0 3.2 2132.0 1608.0 4.33 4.49 0.37 3 4176.2 14.8 47.0 -‐29.6 2.0 2121.0 1583.0 4.18 4.39 0.22 4 3396.4 12.1 59.0 -‐29.8 2.6 1729.0 1268.0 4.03 4.31 0.07 5 3690.2 13.1 72.1 -‐29.4 2.4 1932.0 1406.0 3.90 4.23 0.06 6 3976.2 14.1 86.2 -‐29.2 2.4 2019.0 1438.0 3.67 4.13 0.29 7 2795.6 9.9 96.2 -‐29.4 2.8 1440.4 965.0 3.24 4.01 0.72
Top 8 1079.3 3.8 100.0 -‐29.2 3.0 510.8 308.2 2.98 3.96 0.98 Total 28175.8 100.0 3.96 0.38
(2) Banded MIF Average Layer SG Determina6ons
Layer Dry Mass Mass Cum. Mass M1 M2 M3 M5 Ave. SG Cum. SG SI
No g % % g g g g g/cc g/cc BoYom 1 4217.1 18.9 18.9 -‐28.8 3.0 2171.2 1624.4 4.21 4.21 0.72
2 3701.6 16.6 35.6 -‐28.2 4.0 1908.0 1375.8 3.81 4.01 0.31 3 3594.5 16.1 51.7 -‐28.2 3.8 1774.2 1256.0 3.64 3.89 0.15 4 3406.5 15.3 67.0 -‐27.6 4.8 1753.2 1212.4 3.44 3.78 0.05 5 2813.6 12.6 79.7 -‐29.0 2.8 1435.2 959.0 3.22 3.68 0.27 6 2990.7 13.4 93.1 -‐28.8 3.4 1495.2 956.8 2.95 3.55 0.55
Top 7 1537.7 6.9 100.0 -‐28.8 3.6 778.8 477.4 2.88 3.49 0.61 Total 22261.7 100.0 3.49 0.37
M1= Mass of basket in hair; M2= Mass of “water on basket” in air; M3= Sample in air (+ “Water on basket”); M4= Sample in air M3-‐M2; M5= sample in Water; SG = Specific gravity (= (M4)/[M4-‐(M5-‐M1)]
CONCLUSION
IRON ORE BENEFICIATION AFRICA
Chemical and Physical Proper6es • Essen%al from explora%on to metallurgical
processes development stages; • Ore textures: rela%onships between iron-‐bearing
and gangue minerals – predic%on of the communi%on efficiency
• Breccia-‐textured: clast or matrix supported with angular clasts – Easy to liberate;
• Par%cle size analyse: most par%cles were found in -‐4000μm +2000μm;
• 70 wt.% Fe2O3 in <600 μm Breccia textured MIF;
• 54 wt.% Fe2O3 in <425 μm Banded MIF;
• Mineralogy and density of ore and gangues
• Chemical composition: deleterious elements for the smelting characteristics and product quality;
• Magne%c separa%on vs. Froth Flota%on vs. Gravity Separa%on (cheap and environmental friendly);
• Breccia and Banded MIF materials are high Silicon, low P, low Al and low S.
Amenability to Beneficia6on • Equipment requirements: MDS can only
operates par%cles size between 20 to 1mm • Texture of Breccia and Banded MIF: thickness of
individual clasts and bands (iron-‐rich and chert-‐rich) varies from less than a millimetre
• Recovery and Efficiency:
• MDS not suitable for par%cles less than 1 mm;
• Block the filter and impede the pulsing ac%on;
• Ability to process very fine material will Improve significantly the beneficia%on of iron ore by gravity separa%on;
THANK YOU FOR YOUR ATTENTION
IRON ORE BENEFICIATION AFRICA 2014
ACKNOWLEDGEMENTS:
• N.J. BEUKES for the opportunity and for organizing the finances for this project;
• Jens Gutzmer, for the encouragements and the advices;
• Marius Burger and Willem Grobblar (Assmang Ltd, Iron Ore Division)
• Ashma Singh and Sandi Gcangi (Mintek, Mineral Processing Department)