ZINCOR OPERATIONS - SAIMM · Copsa Mica Boleslaw Port Pirie Huangmu 75.0 80.0 85.0 90.0 95.0 100.0 Total Slab Zinc (kt) Typical Recovery (%) Recovery versus Slab Production Zincor
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ZINCOR OPERATIONS
Contents
• History
• Market
• Process and production data
• Comparisons with other zinc smelters
• Challenges
Corporate History
• 1965: GFSA closes Vogelstruisbult Gold Mine in Springs. Facility is temporarily converted to process uranium
• 1967: Zincor is established (65% GFSA; 35% Iscor)
• 1969, Apr: First ingot cast
• 1999, Feb: GFSA unbundles; Iscor acquires Zincor
• 2001, Nov: Iscor unbundles; mining division of Iscor, including Zincor, is consolidated into a new entity – Kumba Resources
• 2002-2006: Anglo American acquires controlling stake in Kumba Resources
• 2006, Nov: Kumba Resources is unbundled; iron ore business is separated to form Kumba Iron Ore Company; remaining assets and EyesizweCoal are consolidated into a new entity - Exxaro Resources. Zincor is now a division of Exxaro Base Metals
Exxaro Base Metals: 100% Zincor, 26% Black Mt and Gamsberg; 49% of Rosh Pinah; minor shareholding in Chifeng Smelter in China
GFSA – Gold Fields of South Africa
Iscor – now ArcelorMittal South Africa
Slab Production Milestones
• 1969: First ingot is cast
• 1970: 35 kt/a
• 1996: 101 kt/a
• 2002: 111 kt/a
• 2003: 112 kt/a
Zincor’s Role in the Economy
• Zincor is the only primary zinc producer in South Africa
• Slab zinc production of approximately 100 kt/a with inherent capacity up to 115 kt/a
• Sulphuric acid production of approximately 170 kt/a. Supplies 25% of traded sulphuric acid market
Domestic Market: Zinc
74%
4%
3%
19%
Market: Zinc and Acid Usage
Total Galvanizing73%
Zinc Alloys9%
Total Battery2%
Total Chemical9%
Total Other<1%
Brass Alloys7% Sasol
17%
Fertilisers6%
Distributors54%
Other Cust.20%
Exporters3%
Zinc Sulphuric Acid
Product Range: Zinc
Production by TeckCominco, Canada. Distributed by Zincor to general galvanisers. Mitigate effects of reactive steels on galvanising process
1% Ni-Zn master alloyNickel alloy
* CGL – continuous galvanizing line
CGL’s only – ArcelorMittal and Duferco0.6% Al Pre-alloy jumbo ingots
CGL’s and general galvanisers for Al additions to pots
10% Al alloyZincal-10
Battery manufacturer and general galvanisers0.95 – 1.35% PbZn 4
Battery manufacturerSub-grade – Low Cd
Galvanising customers, excluding CGL’sSub-grade – High Pb
Galvanising customers, including CGL’s*Min 99.95% ZnZn 2
Customers requiring lowest impurities
Spot exports
Min 99.995% ZnSHG
UseCompositionGrade
Supply and Product Chain
ZINCOR
IntermediateFertilizerProduct
GalvanisingAlloys
BatteriesChemicals
Chemical Process Applications
AutomotiveTransport
General ConsumersInfrastructureConstruction
Raw Materials Smelter
SulphuricAcid
Zinc metal
Agricultural Industry
Primary Consumers Final Consumers
Primary Consumers Final Consumers
Rosh PinahBlack Mountain
Imports(ZnS)
ZnO(from DRC)
Production Data
112115
176650
105620
165325
103686
170873
92967
129045
101989
153497
89033
129508
60000
80000
100000
120000
140000
160000
180000
Tonn
es
2003 2004 2005 2006 2007 2008
Zinc Acid
2004: Shortage of concentrate2005 – 2007: Poor concentrate grade2006 – 2008: Roaster rebuild
Process Flowsheet
H2S04
Acid Plant
Impure ZnS04
ROASTING
Calcine (Zn0)
S02
residue
Impure ZnS04
Cd CakePurified ZnS04
Cathode Zinc
Zinc products
spent
Concentrate
Dross to process/sale
ZnS
Residue Dam
EFFLUENT TREATMENT
Weak acid bleed to Effluent Treatment
Solution to evaporation dam
Pb/Ag residue
Bleed to treatment
Cu/Co/As Cake
RESIDUE TREATMENT
solutionsolids
calcine
spen
t
Drossex melting
Conc. H2SO4
NEUTRAL LEACH
ELECTROWINNING
Cu Cement
Zn dust to PurificationMELTING/CASTING
PURIFICATIONFe residue
Washed Oxide
Purification
Upgraded Cd Cake
to storage
Impure ZnS04
Zinc Dust
Cu/Co Removal
As2O3 soln
Filtration
Cd Removal
Zinc Dust
Cu/Co/As Caketo further
processing
Filtration
Cd Scavengercake
Hot Purified solution
To Neutral Leach
Cd Upgrading
Spentstorage
Cd-free, Zn-rich solution with Cu solids
To Purified Solutionstorage/Gypsum RemovalZno + M++ = Mo + Zno;
M = Cu, Co, Ni and Cd
Cu Cementation
Cu Cement to storage
Cu-sulphateproduction
Zinc Dust
Spent
Zinc Dust
Filtration
Cell House
• 44 banks; 12 cells/bank; 528 cells
• 21,120 cathodes; 21,648 anodes
• Cathode area: 1.23 m²
• Anodes – 10 mm thick; Pb-Ag-Ca-Al; 0.5% Ag; 0.06% Ca; 0.012 %Al
• Cathodes – 7 mm; 1050 Al alloy
• Cathode current density: 508 –569 A/m2
• Deposition time: 24 hours
• Cathode life = 2 years
• Anode life = 6.5 years
Residue Treatment
Hot Acid Leach
Steam
Neutral Leach Residue
Thickener
Super Hot AcidLeach
SteamConc. H2S04
Weak AcidLeach
Thickener
Pb/Ag Residueto Tailings
Water
O/F
U/F
O/F
U/F
Filtrate
Thickener
Belt Filter
Spent electrolyte
U/F
Solution to Fe Precipitation
Spent electrolyte
O/F
Iron Removal
ZnSO4 Solution to Neutral Leach
Calcine
Iron Precipitation
Fe Residueto Tailings
O/F
U/F
Slurry tank
Water
Spent electrolyte
FiltrateBelt Filter
Thickener
Steam
Slurry tank
Zn OxideProcess
Water
Fe solution(from Weak Acid Leach thickener)
Iron Residue Composition
16.2
1:1
96.7
8.5
40
VM -Goethite
1:1.31: 1.51:1 Fe:Acid
19.2
94.6
10
34
Para-goethite
113.5Zn content, %
3529Fe content, %
2322.5Fe residue, t/100 t concentrate
93.5**97.9Overall Zn recovery, %
Zincor *Jarosite
* paragoethite with 50% oxides)** best
Zinc Industry
• Global slab production in 2008 was 11.6 Mt
• Over 90% of zinc is produced by electrolysis
• Largest smelters: San Juan de Nieva - 480 kt/a; Onsan – 450 kt/a
• Last cyclical peak was in 2006; price peaked at US$4500/t
• Pricing in 2009 is expected to stabilise at $1270/t
• Next predicted cyclical peak is in 2014
• Key to survival, apart from economy of scale: high zinc recovery, diversified product range and by-product recovery
Global Smelter Slab Production (kt/a)
Source: Data from Brook Hunt :
0
50
100
150
200
250
300
350
400
450
500
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(IS
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ISF
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arta
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Zincor
92.5
0
50
100
150
200
250
300
350
400
450
500
Ons
an
Odd
a
Kam
ioka
Nor
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am
Juiz
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For
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(EL)
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(VR
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(Fan
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Cop
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Bol
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w
Por
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Hua
ngm
u 75.0
80.0
85.0
90.0
95.0
100.0
Total Slab Zinc (kt) Typical Recovery (%)
Recovery versus Slab Production
Zincor
73% of Zn is produced at recoveries above 95%
Source: Data from Brook Hunt
Challenges
Environmental issues
• Current residue disposal facility is nearing end of life
• Construction of new a facility and closure of existing one
• Treatment of discharge water to remove sulphates in the near future, in line with new environmental legislation
Electrical Energy
• Uncertainty over electrical energy capping for the next four years
Skills
• A general shortage of skills – common to most industries in South Africa
Challenges
Raw Materials Supply
• Uncertain long-term supply of local concentrates
• High transportation cost associated with imported material
Product Range• Need to diversify value-added product range:
- increase CGL grade production- grow local market for Ni-alloy
• Extract maximum value from associated base metals
Challenges
Metallurgical issues
Zincor needs to increase zinc recovery to 95%:
• Fuming technology, as practiced by Korea Zinc, is the most appropriate technology to treat residues and maximise recovery. This technology is not an option at present due to uncertainty in long-term local concentrate supply and high capital investment
• Eliminate use of calcine in Fe Removal circuit by increased use of fumed zinc oxide as well as basic zinc sulphate
• Recovery of soluble zinc from solution run-off from residue dam as a basic zinc sulphate
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