corby anderson

The Effective Hydrometallurgical

Treatment of Arsenic Bearing Copper

Ores and Concentrates

Eur Ing Dr. Corby G. Anderson QP CEng FIMMM FIChemE

Harrison Western Professor

Kroll Institute for Extractive Metallurgy

Colorado School of Mines

Golden, Colorado USA 80401

CORNISH MAN ENGINE

MOUNTAIN MINE CIRCA 1850

Allihies, Beara Peninsula, Cork, Ireland

PERUMIN

30th Convencion Minera

ANCESTORS - ANACONDA SMELTER

The Stack was built by the Alphons Custodis Chimney Construction Company of New York. At the time it was built,

May 5, 1919 it was the tallest masonry structure of any kind in the world at 585 feet.

PERUMIN


Butte, Montana, USA

Granite Mountain Fire Memorial

June 8, 1917 – 168 Men Died

Dr. Corby G. Anderson

PERUMIN


Big Creek, Idaho, USASunshine Fire - May 2, 1972 - 91 Men Died

PERUMIN



• Est. 1874

• Golden, Colorado

• 21 majors

• 193 Faculty

• 4300 students

• “…have a unique mission in energy, mineral, and materials science and engineering…”

PERUMIN


Department of Metallurgical & Materials

Engineering - MME

• 20 full time faculty members

• 5 Centers and Institutes:

–– Kroll Institute for Extractive MetallurgyKroll Institute for Extractive Metallurgy– Colorado Center for Advanced Ceramics

– Advanced Steel Processing & Products Res. Ctr.

– Center for Welding, Joining & Coating Research– Center for Welding, Joining & Coating Research

– Advanced Coatings & Surface Engineering Res. Ctr.

• Degrees:– PhD, MS, ME & BS in Metallurgical & Materials Engineering

– PhD & MS in Materials Science

– PhD & MS in Nuclear Engineering

• Students:– Graduate level: 120

– Undergraduate level: 50 per year

PERUMIN


KIEM KIEM -- Kroll Institute for Extractive Metallurgy &CCRR 33 -- Center for Resource Recovery & RecyclingCenter for Resource Recovery & Recycling

Patrick R. Taylor Gerard P. Martins Brajendra Mishra Corby G. Anderson D. Erik Spiller Paul B. Queneau

Director, KIEM

G.S. Ansell

Distinguished

Professor of

Chemical

Metallurgy

EXPERTISE

�Mineral Processing

�Extractive Metallurgy

�Recycling

�Waste Treatment &

Minimization

�Thermal Plasma

Processing of Materials

�Thermal Plasma

Processing of Wastes

Professor of

Metallurgical and

Materials Engineering

EXPERTISE

�Process and

extraction metallurgy

�Engineered ceramic

and metal powders

�Electrochemical

systems

�Corrosion

�Transport phenomena

�Reactor Design &

kinetics

Director, CR3

Associate Director

KIEM, Professor of

Metallurgical and


EXPERTISE

�Pyrometallurgy

�Electrochemistry

�Materials synthesis

�Waste Processing

�Recycling

�Molten Salt

Processing

�Oxidation

�Reactive &

radioactive metals

�Glove box processing


of Metallurgical and


EXPERTISE

�Extractive Metallurgy


�Recycling

� Waste Treatment &

Minimization

Research Professor of

Metallurgical and


EXPERTISE


�Comminution

�Physical separation

�Recycling

�Flotation

�Leaching

�Liquid-solid

separation

�Project management

Research Professor of

Metallurgical and

Materials

Engineering

EXPERTISE

�Extractive and

process metallurgy

�Pyrometallurgy

�Recycling

�Waste treatment

and minimization

PERUMIN


KIEMKIEM

The Kroll Institute for Extractive Metallurgy The Kroll Institute for Extractive Metallurgy -- KIE MKIEMDepartment of Metallurgical and Materials Engineeri ngDepartment of Metallurgical and Materials Engineeri ngColorado School of MinesColorado School of Mineswww.mines.eduwww.mines.edu

ARSENIC

PERUMIN


ARSENIC

Name: Arsenic Symbol: As Atomic Number: 33 Atomic Mass: 74.9216 amuMelting Point: 817.0 °C (1090.15 K, 1502.6 °F) Boiling Point: 613.0 °C (886.15 K, 1135.4 °F) Boiling Point: 613.0 °C (886.15 K, 1135.4 °F) Number of Protons/Electrons: 33 Number of Neutrons: 42 Classification: MetalloidCrystal Structure: RhombohedralDensity @ 293 K: 5.72 g/cm3

Color: Gray

PERUMIN


ARSENIC

PERUMIN


MERCURY

PERUMIN


MERCURY

Name: Mercury

Symbol: Hg

Atomic Number: 80

Atomic Mass: 200.59 amu

Melting Point: -38.87 °C (234.28 K, -37.966 °F)

Boiling Point: 356.58 °C (629.73 K, 673.844 °F) Boiling Point: 356.58 °C (629.73 K, 673.844 °F)

Number of Protons/Electrons: 80

Number of Neutrons: 121

Classification: Transition Metal

Crystal Structure: Rhombohedral

Density @ 293 K: 13.456 g/cm3

Color: Silver

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MERCURY

PERUMIN


MERCURY

Aktashite Cu6Hg3As4S12

Cinnabar HgS

Clearcreekite Hg (CO3)(OH)• 2H2O

CorderoiteHg3S2(Cl,Br)2

Kadyrelite Hg H(Br,Cl)3O2

Livingstonite HgSb4S8

Moschellandsbergite Ag2Hg3

Mosesite Hg N(Cl,SO ,MoO ,CO )•(H O) Mosesite Hg2N(Cl,SO4,MoO4,CO3)•(H2O)

Myrickite Cinnibar in Quartz

RouthieriteTl(Cu,Ag)(Hg,Zn)2(As,Sb)2S6

Terlinguaite Hg2OCl

Tiemannite HgSe

Montroydite HgO

Calomel HgCl

PERUMIN


ANTIMONY

PERUMIN


ANTIMONY

Name: Antimony

Symbol: Sb

Atomic Number: 51

Atomic Mass: 121.76 amu

Melting Point: 630.0 °C (903.15 K, 1166.0 °F)

Boiling Point: 1750.0 °C (2023.15 K, 3182.0 °F)

Number of Protons/Electrons: 51

Number of Neutrons: 71 Number of Neutrons: 71

Classification: Metalloid

Crystal Structure: Rhombohedral

Density @ 293 K: 6.684 g/cm3

Color: bluish

PERUMIN


ANTIMONY

PERUMIN


Technical Routes of Treatment

Pressure Oxidation

Roasting

Selective Leaching of Impurities

PERUMIN



Pressure Oxidation

Advantage: Proven technology.

Disadvantage: High costs and complex plant Disadvantage: High costs and complex plant design and operation.

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Roasting

Advantage: Proven technology.

Disadvantage: Challenges in containment Disadvantage: Challenges in containment and fixation of impurities.

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Selective Leaching of Impurities

Advantage: proven technology with moderate costs and control and fixation of contaminants.

Disadvantage: Established technology but not well known.

PERUMIN


ANDERSON ENARGITE PROJECTS

Marca Punta - Peru

El Galeno - Peru

Caspiche – Chile

Chelopech - Bulgaria

Lepanto – Phillipines

Tampaken – PhillipinesTampaken – Phillipines

Frieda River - New Guinea

Golpu – New Guineau

Mt. Carlton – Australia

El Indio - Chile

PERUMIN


Hydrometallurgical Processing of Gold

Bearing Copper Enargite Concentrates

Dr. Corby G. AndersonDr. Larry G. Twidwell

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Alkaline Sulfide Leaching Copper Concentrate

Industrial Plants

ASLASL -- Sunshine Mining 1945 Sunshine Mining 1945 –– 20022002

11stst and Longest Operating Copper and Longest Operating Copper Concentrate Alkaline Sulfide Leach Concentrate Alkaline Sulfide Leach Concentrate Alkaline Sulfide Leach Concentrate Alkaline Sulfide Leach Plant.Plant.

Produced Produced SbSb metal and removed metal and removed Hg and As providing clean Cu Hg and As providing clean Cu smelter concentrate.smelter concentrate.

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Nitrogen Species Catalyzed Leaching Copper

Concentrate Industrial Plants

NSCNSC -- Sunshine Mining 1984 Sunshine Mining 1984 ––19951995

11stst and Longest Operating and Longest Operating Copper Concentrate Pressure Copper Concentrate Pressure Leach Plant.Leach Plant.

Produced Ag and Cu.Produced Ag and Cu.

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Nitrogen Species Catalyzed Leaching

Copper Concentrate Industrial Plants

Sunshine Mining 1984 Sunshine Mining 1984 –– 19951995

11stst and Longest Operating and Longest Operating 11 and Longest Operating and Longest Operating Copper Concentrate Pressure Copper Concentrate Pressure Leach Plant.Leach Plant.

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Industrial Copper Pressure

Leach History

Anaconda Arbiter ProcessAnaconda Arbiter Process 19741974

SunshineSunshineMiningMining 19841984

Mt. GordonMt. Gordon 19981998Mt. GordonMt. Gordon 19981998

Phelps DodgePhelps Dodge 20032003

OxianaOxiana 20052005

KansanshiKansanshi 20052005PERUMIN


Nitrogen Species Catalyzed

Metallurgical Uses

–– Dissolution of Yellow CakeDissolution of Yellow Cake

–– Dissolution of Spent Uranium Fuel ElementsDissolution of Spent Uranium Fuel Elements

–– Pickling Agent for Stainless SteelPickling Agent for Stainless Steel–– Pickling Agent for Stainless SteelPickling Agent for Stainless Steel

–– Uranium Concentrate LeachingUranium Concentrate Leaching

–– Leaching of Phosphate RockLeaching of Phosphate Rock

–– 1st Proposed 1909 for Metal Sulfide Oxidation1st Proposed 1909 for Metal Sulfide Oxidation

PERUMIN



Leaching Fundamentals

3 MeS (S)+ 2HNO3 (Aq)+ 3H2SO4 (Aq) ��

3 MeSO4 + 3So (S) + 2NO (G) + 4H2O

NaNO2 (Aq) + H+ �� HNO2 (Aq) + Na+

HNO2 (Aq) + H+ �� NO+ (Aq) + H2O

2MeS (S) + 4NO+(Aq) �� 2Me+2

(Aq) + 2So + 4NO (G)

PERUMIN




Relative Potentials of Hydrometallurgical Oxidizers.

E0hOxidant

Redox Equation (pH = 0, H2 ref.)

Fe+3 Fe+3 + e- �� Fe+2 0.770 VFe+3 Fe+3 + e- �� Fe+2 0.770 V

HNO3 NO3- + 4H+ +3e- �� NO(g) + 2H2O 0.957 V

HNO2 NO2 - + 2H+ + e- �� NO(g) + H2O 1.202 V

O2 (g) O2 + 4H+ + 4e- ��2H2O 1.230 V

Cl2 (g) Cl2 (g) + 2e - �� 2 Cl- 1.358 V

NO+ NO+ + e- �� NO(g) 1.450 V

PERUMIN




2NO (G) + O2 (G) < --> 2NO2 (G)

2NO2 (G) <--> 2NO2 (Aq)2NO2 (G) <--> 2NO2 (Aq)

2NO2 (Aq) + 2NO (Aq) + 4H+ <--> 4NO+ (Aq) + 2H2O

PERUMIN


2MeS (G) + 4H+ + O2 (G) �� 2Me+2(Aq) + 2So + 2H2O



PERUMIN


NSC Process Advantages

1.1. First and Only Long Term Industrial Pressure First and Only Long Term Industrial Pressure Leach Process for Copper ConcentratesLeach Process for Copper Concentrates

2.2. Faster Reaction RateFaster Reaction Rate3.3. Smaller Reaction Autoclave Volume RequiredSmaller Reaction Autoclave Volume Required4.4. Eh/ORP Very HighEh/ORP Very High5.5. No Exotic/Expensive Materials of ConstructionNo Exotic/Expensive Materials of Construction5.5. No Exotic/Expensive Materials of ConstructionNo Exotic/Expensive Materials of Construction6.6. No Titanium NeededNo Titanium Needed7.7. No Fire DangerNo Fire Danger8.8. No Oxygen Dip TubeNo Oxygen Dip Tube9.9. Low Autoclave Temperatures (125Low Autoclave Temperatures (125ooC or170C or170ooC)C)10.10. Low Pressures (620 Low Pressures (620 kPagkPag or 975 or 975 kPagkPag))

PERUMIN


NSC Process Advantages

11.11. No Brick or Lead Autoclave LinersNo Brick or Lead Autoclave Liners12.12. Less and Simpler Autoclave MaintenanceLess and Simpler Autoclave Maintenance13.13. No Special Agitator System for ONo Special Agitator System for O22 Mass Transfer toMass Transfer to

SolutionSolution14.14. Easier Feed Pump, Choke and Flash System DesignEasier Feed Pump, Choke and Flash System Design

and Operation along with Direct Heat Exchange/Recovery and Operation along with Direct Heat Exchange/Recovery 15.15. Like Smelting, Au and Ag Recovery is ExcellentLike Smelting, Au and Ag Recovery is Excellent16.16. No Complex Chloride Chemistry or Corrosion toNo Complex Chloride Chemistry or Corrosion to16.16. No Complex Chloride Chemistry or Corrosion toNo Complex Chloride Chemistry or Corrosion to

Deal with.Deal with.17.17. No Major Economic or Environmental IssuesNo Major Economic or Environmental Issues

Because of Limited Nitrogen Species Use in ProcessBecause of Limited Nitrogen Species Use in Process18.18. Lower Capital and Operating CostsLower Capital and Operating Costs19.19. Simple, Industrially Proven BySimple, Industrially Proven By--Product Sulfur Handling Product Sulfur Handling

Results in Value Added Products or Regenerated Reagents.Results in Value Added Products or Regenerated Reagents.

PERUMIN



Current Applications-- Copper Copper EnargiteEnargite Concentrates : South AmericaConcentrates : South America

–– Molybdenum Disulfide/Rhenium Concentrates : Molybdenum Disulfide/Rhenium Concentrates : United StatesUnited States

–– Gold Pyrite Concentrates : ChinaGold Pyrite Concentrates : China

–– Gold Gold ArsenopyriteArsenopyrite Concentrates : AsiaConcentrates : Asia–– Gold Gold ArsenopyriteArsenopyrite Concentrates : AsiaConcentrates : Asia

–– Gold Pyritic Tailings : South AmericaGold Pyritic Tailings : South America

–– Silver Bearing Concentrates and Pyritic Ores : So uth Silver Bearing Concentrates and Pyritic Ores : Sout h AmericaAmerica

-- Copper, Zinc, Nickel, Cobalt PM’s Copper, Zinc, Nickel, Cobalt PM’s –– AustraliaAustralia

-- Cobalt, Copper, Gold Cobalt, Copper, Gold –– United States United States –– Detailed Detailed Design UnderwayDesign Underway

PERUMIN


Partial Nitrogen Species

Catalyzed Oxidation of a

Copper Enargite Concentrate

Composition of Enargite Concentrate Tested

Cu, % Fe, % As, % Au, g/T Tot. S. % p80 %

19.7 24.3 5.4 4.3 34.3 25 micron19.7 24.3 5.4 4.3 34.3 25 micron

PERUMIN


PERUMIN


STAT EASE

This commercially licensed program based on

fundamentals of design of experimentation provides

highly efficient:

Two-level factorial screening studies so that the vital

factors which affect a process can be identified.factors which affect a process can be identified.

Response surface methods to find ideal process

settings and achieve optimal performance.

Mixture design techniques to discover optimal

outcomes.

PERUMIN


STAT EASE

The ‘Google’ product of applied testing and optimization.

Industrial laboratory testing and optimization clients

want;

Maximum results

Short turnaround

Low cost

Usually they have minimal amounts of representative

samples.

PERUMIN


DOE NSC MATRIX

TABLE 1. STAT EASE DESIGN EXPERT ¼ TEST MATRIX.

Std Run Grind Time Initial Acid Max. Temp. Leach Time

1 1 0 min 50 g/L 150 C 120 min

7 2 0 min 100 g/L 130 C 60 min

5 3 0 min 50 g/L 150 C 60 min

10 4 5 min 75 g/L 140 C 90 min10 4 5 min 75 g/L 140 C 90 min

3 5 0 min 100 g/L 130 C 120 min

4 6 10 min 100 g/L 150 C 60 min

6 7 10 min 50 g/L 130 C 120 min

2 8 10 min 50 g/L 130 C 60 min

8 9 10 min 100 g/L 150 C 120 min

9 10 5 min 75 g/L 140 C 90 min

PERUMIN


NSC TEST CONDITIONS

TABLE 2. NSC ENARGITE PARTIAL OXIDATION


Partial Oxidation Leach Conditions.

Grind Time = Table 1

Initial Free Sulfuric Acid = Table 1Initial Free Sulfuric Acid = Table 1

Reactor Working Pressure = 620 kPag

Slurry Solids Content = Table 1

Maximum Temperature = Table 1

Total Time = Table 1

Nitrogen Species Concentration = 2.0 g/L

PERUMIN


NSC DOE TEST RESULTS

TABLE 3. NSC TESTING RESULTS

Std Run As Rec. Cu Rec Fe, Rec

1 1 38.21 % 38.96 % 80.57 %

7 2 18.34 % 26.56 % 84.15 %

5 3 27.75 % 30.03 % 80.34 %

10 4 48.44 % 53.81 % 78.55 %

3 5 11.38 % 19.18 % 58.29 % 3 5 11.38 % 19.18 % 58.29 %

4 6 29.73 % 74.39 % 1.07 %

6 7 65.63 % 68.80 % 69.92 %

2 8 58.99 % 86.92 % 32.17 %

8 9 53.30 % 55.97 % 65.92 %

9 10 48.44 % 53.81 % 78.55 %

PERUMIN


NSC STAT EASE MODEL

Final Copper Equation in Terms of Actual Factors

Cu Recovery =

+62.98042

+4.2837 * Grind Time

-0.12732 * Solids

-0.28707 * Initial Acidity

-0.026375 * Temperature

+0.061833 * Leach Time+0.061833 * Leach Time

+2.13467E-003 * Solids * Initial Acidity

-2.76833E-003 * Solids * Leach Time

Std. Dev. 0.000 R-Squared 1.00

Mean 50.84 Adj R-Squared 1.00

PERUMIN


NSC STAT EASE RESPONSE

DESIGN-EXPERT Plot

Cu RecoveryDesign Points

X = B: SolidsY = C: Initial Acidity

Actual FactorsA: Grind Time = 10.0D: Temperature = 130.0E: Leach Time = 60.0

Cu Recovery

C: Initial Acidity

62.5

81.3

100.0

76.0

72.8

B: Solids

C: Initial Acidity

50.0 62.5 75.0 87.5 100.0

25.0

43.8

62.5

81.0

PERUMIN


NSC STAT EASE RESPONSE

DESIGN-EXPERT Plot

As RecoveryX = B: SolidsY = C: Initial Acidity

Actual FactorsA: Grind Time = 10.0D: Temperature = 140.0E: Leach Time = 60.0

As Recovery

C: Initial Acidity

81.3

100.0

43.955.0

51.0

48.7

B: Solids

C: Initial Acidity

50.0 62.5 75.0 87.5 100.0

25.0

43.8

62.5

34.6

39.3

43.955.0

PERUMIN


NSC STAT EASE RESPONSES Oxidized, %

44

63

81

100

26.0

28.0

30.0

33.1

32.0

32.0

Initial

Acidity, g/L

Influence of initial acidity and solids content on sulfur oxidized

(Constants: Grind Time, 10 min; T 130 C; Leach Time, 60 min)

Solids, g/L

50 63 75 88 100

25

26.0

24.0

PERUMIN


NSC STAT EASE RESPONSEAcid Generation, g/g concentrate

44

63

81

100

0.40

0.60

0.30

0.10

0.20

Initial

Acidity, g/L

Solids, g/L

50 63 75 88 100

25

44

0.05

Influence of initial acidity and solids content on acid generation

(Constants: Grind Time, 10 min; T 130 C; Leach Time, 60 min)

PERUMIN


OPTIMIZED NSC

PARTIAL OXIDATION


Partial Oxidation Leach Conditions.

Grind Time = 25 minutes

Initial Free Sulfuric Acid = 25 g/L


Slurry Solids Content = 50 g/LSlurry Solids Content = 50 g/L

Maximum Temperature = 130 C

Total Time = 60 minutes


Copper Recovery = 95.01 %

Iron Recovery = 78.46 %

Arsenic Recovery = 86.93 %

Acid Generation = 0.125 g/g Concentrate

% Sulfur Oxidized to Solution = 67.11

PERUMIN


Leaching Cycles = 8

Grind Time = 40 minutes

Initial Free Sulfuric Acid = 25 g/L


Slurry Solids Content = 50 g/L

Maximum Temperature = 130 C

Total Leach Tine = 45 minutes


Particle Size = 80% passing 15 micron

OPTIMIZED LOCKED CYCLE NSC PARTIAL OXIDATION

Particle Size = 80% passing 15 micron

Copper Recovery = 97.8 %

Iron Recovery = 51.2 %

Arsenic Recovery = 72.1 %

Mass Reduction = 64.91 %

Acid Generation = 0.06 g/g Concentrate

% Sulfur Oxidized to Solution = 62.66 %

Oxygen Consumption = 0.891 g/g concentrate

PERUMIN


ARSENIC REMOVAL AND FIXATION

Three methods for removing arsenic from solution

were investigated:

Elevated Ambient Temperature Formation of Scorodite

Autoclave Formation of ScoroditeAutoclave Formation of Scorodite

Ambient Temperature (25 C) Removal of Arsenic by

Ferrihydrite Formation and Adsorption

PERUMIN


Scorodite was produced to be used as seed for subsequent experiments

by precipitation from one-liter of 0.3 M Ferric Nitrate, 25 g/L As(V)

solution at 160 C, 24 hours.

PERUMIN


Autoclave Formation of Scorodite

Autoclave leach solution-1 was pH adjusted to 1.06 and

subjected to autoclave precipitation. The experimental test

conditions were: 1-liter of solution was placed in the autoclave.

20-g/L of scorodite seed was added, the temperature was

raised to 160 C, held for 5-hr. The results are presented in the raised to 160 C, held for 5-hr. The results are presented in the

next slide This approach was successful and may be a viable

option, i.e. the arsenic is effectively removed as scorodite, yet

little copper is lost to the solids.

PERUMIN



Solution pH Removed from Solution,% (final conc, mg/L)

As Cu

1.06 Head 0 (1760) 0 (7262)

1.11 97.9 (36.5) 1.9 (7127)1.11 97.9 (36.5) 1.9 (7127)

Final phase formed confirmed by XRD is scorodite.

PERUMIN



PERUMIN


Ambient Temperature (25 C) Removal of

Arsenic by Ferrihydrite Formation and Adsorption

Solution pH Concentration, mg/L

As Fe Cu

0.7 (head) 2774.0 11720.0 8352.0

3.1 105.94 823.7 8681.43.1 105.94 823.7 8681.4

4.0 6.78 139.5 8151.2

4.5 <0.03 DL 52.0 5221.7

4.6 <0.03 DL 48.4 4396.4

5.0 <0.03 DL 44.0 2568.3

PERUMIN


Removal by Ferrihydrite Adsorption

8000

10000

12000

[M],

mg/

L As

Ambient Temperature (25 C) Removal of

Arsenic by Ferrihydrite Formation and Adsorption

0

2000

4000

6000

0 1 2 3 4 5

pH

[M],

mg/

L As

Fe

Cu

PERUMIN


NSC Partial Oxidation Enargite Flowsheet

Enargite Concentrate

H2SO4 NaNO2 O2

Solids to ASL Gold Recovery

BALL MILL

MIXING TANK

AUTOCLAVE

THICKENER

Split Thickener Overflow A

Split T

hickener Overflow

B

Solids to ASL Gold Recovery

Scorodite

Copper Cement

Ferrihydrite Precipitation

Copper Metal

AUTOCLAVE (for Scorodite)

FILTER PRESSFILTER

PRESS

FILTER PRESS

MIXER SETTLER TANKELECTROWINNING

CELL

CEMENTATION TANK

Copper Solution

Raffinate

Iron Metal

Split T

hickener Overflow

B

PERUMIN


Cu, % Co, % Fe, % As, % Au, Total S,

Partial Nitrogen Species Catalyzed Pressure

Oxidation of a Cobaltite Chalcopyrite Concentrate

It is now proposed that the NSC pressure leach facility be used to treat a gold bearing

chalcopyrite and cobaltite concentrate. NSC concentrate leach testing has been

conducted at and the results were as follows.

Table 35.Composition of Concentrate Tested.

Cu, % Co, % Fe, % As, % Au, o/T

Total S, %

7.2 14.4 14.4 20.0 0.42 19.0

PERUMIN


Operating Criteria Unit

Initial Free Sulphuric Acid 100 g/L

Reactor Working Pressure 620 kPag

Slurry Solids Content 100 g/L

Solids Size 80% -10 micron

Maximum Temperature 125°C

Nitrogen Species Catalyzed Partial Nitrogen Species Catalyzed Partial Nitrogen Species Catalyzed Partial Nitrogen Species Catalyzed Partial Oxidation Leach Conditions.Oxidation Leach Conditions.Oxidation Leach Conditions.Oxidation Leach Conditions.

Maximum Temperature 125°C

Nitrogen Species Concentration

2.0 g/L

Reaction Time 20 min

PERUMIN


Cu,

%

Co, %

Fe, %

As %

Au, %

Mass Distribution of Nitrogen Species Catalyzed PressureMass Distribution of Nitrogen Species Catalyzed PressureMass Distribution of Nitrogen Species Catalyzed PressureMass Distribution of Nitrogen Species Catalyzed PressureLeaching of Cobaltite, Chalcopyrite Gold Concentrate.Leaching of Cobaltite, Chalcopyrite Gold Concentrate.Leaching of Cobaltite, Chalcopyrite Gold Concentrate.Leaching of Cobaltite, Chalcopyrite Gold Concentrate.

As seen the copper, cobalt and arsenic are solubilized and can be separated by conventional means with the sulphide oxidized to sulphurin a minimum amount of time.The gold is concentrated in the solids forrecovery by alkaline sulphide leaching solids.

% % % % %Solution 97.3 97.7 97.7 93.40.0 Solid 2.7 2.3 2.3 6.6 100.0

PERUMIN


�Very selective lixiviant.

� Only As, Hg, Sb, Au and Sn have

significant solubilities.

Alkaline Sulfide Hydrometallurgy

Fundamentals

� Used industrially for Sb production in,

USA, USSR and China.

� Piloted for Sb and Au in Australia

PERUMIN



Current Applications

---- Antimony and PM : Australia and EuropeAntimony and PM : Australia and Europe

–– Gold Pyrite Concentrates : ChinaGold Pyrite Concentrates : China

–– Gold Gold ArsenopyriteArsenopyrite Concentrates : AsiaConcentrates : Asia

–– Gold Pyritic Tailings : South AmericaGold Pyritic Tailings : South America

–– Copper Copper EnargiteEnargite : South America: South America

-- Copper Copper EnargiteEnargite : Asia/South Africa: Asia/South Africa

-- Copper Copper EnargiteEnargite : Asia./Australia: Asia./Australia

PERUMIN


Alkaline Sulfide Hydrometallurgy - Sulfur Stability

Diagram.


Fundamentals

PERUMIN


4S + 6OH- → 2S2- + S2O32- + H2O

(X-1)S + S2- → S2-X (where X = 2 to 5)

S 2- + 2(X-1)e- → xS2-


Fundamentals

SX2- + 2(X-1)e- → xS2-

S22- + 2e- → 2S2-

PERUMIN



Fundamentals

Alkaline Sulfide Hydrometallurgy - Sulfur Meta Stable Diagram.

PERUMIN


Alkaline Sulfide SolutionsAlkaline Sulfide Hydrometallurgy

Fundamentals

PERUMIN


Na2S + As2S3 �� 2NaAsS2

NaAsS2 + Na2S �� Na3AsS3


Fundamentals

1.5 H2O + 2 Na2S + ½ As2O3 ��NaAsS2 + 3 NaOH

NaAsS2 + Na2S �� Na3AsS3

PERUMIN


Na3AsS4 + 2 O2 � Na3AsO4

2 O2 + Na2S � Na2SO4

3.5 O2 + 2NaOH + Na2S2 � 2Na2SO4 + H2O

8 O2 + 8NaOH + Na2S5 � 5Na2SO4 + 4H2O

2NaOH + 2 O + Na S O � 2Na SO + H O


Fundamentals

2NaOH + 2 O2 + Na2S2O3 � 2Na2SO4 + H2O

Arsenic is then precipitated by iron salt addition.

PERUMIN


Alkaline Sulfide Waste Solution Treatment

• ~ 100% sulfide oxidation to sulfate

• Sodium sulfate crystals were precipitated from the treated

solution

• XRD scans confirmed Na2SO4

PERUMIN


Sodium Sulfate (Na2SO4) and Gypsum (CaSO4)

As a Value Added By-product or for Sodium Hydroxide Regeneration


Pulp and Paper Manufacture, Glass Industry, Ceramic Industry,

Detergents, Feed Supplements, Textile Dyes, Bleaching,

Photography

Sodium Sulfate

Photography

Soil Amendment for Agriculture or Cement Manufacture

Key Reagent Regenerations from Sodium Sulfate

Sulfuric Acid and Caustic Required for Process

Ammonium Sulfate Fertilizer can be Produced

Gypsum

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2O2 + Na2S �� Na2SO4

3.5O2 + 2NaOH + Na2S2 �� 2Na2SO4 + H2O

8O2 + 8NaOH + Na2S5 �� 5Na2SO4 + 4H2O

2NaOH + 2O2 + Na2S2O3 �� 2Na2SO4 + H2O

Sodium Sulfate Production

Gypsum Production


Na2SO4 + Ca(OH)2 �� CaSO4 + NaOH

Key Reagent Regeneration Reactions from Sodium SulfateNa2SO4 + 2H2O �� H2SO4 + 2NaOH

Or

2NH4OH + Na2SO4 ⇄⇄⇄⇄ 2NaOH + (NH4)2SO4

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Laboratory Electrodialysis Cell.

Key Reagent Regeneration Reactions from Sodium SulfateNa2SO4 + 2H2O �� H2SO4 + 2NaOH

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Gold lixiviation in the alkaline sulfide system

postulated to be the result of oxidation by

polysulfide and complexation as a sulfide .

Leaching may occur as;

Au + S AuS + e-

EPD 2003, March 2-6

Auo + S5-2 � AuS5

- + e-

Recovered by EW, cementation, chemical or

gaseous precipitation, IX, SX.

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Alkaline Sulfide Gold Leaching Design of Experiments

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Alkaline Sulfide Gold Leach Head Solution Assay.

Volume L Au Sb As Hg Sn

Alkaline Sulfide Gold Recovery

Adsorption


0.5 88.7 ppm 21.0 g/L 5.31 g/L 274 ppm 1.84 g/L

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Alkaline Sulfide Gold Leach Head Final Assay.



Adsorption

0.5 1.5 ppm 21.1 g/L 5.21 g/L 274 ppm 1.89 g/L

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Overall Gold Selectivity and Recovery.

Liquid Solid

Gold 1.7% 98.3%

Antimony 100.0% 0.0%


Adsorption

Antimony 100.0% 0.0%

Arsenic 100.0% 0.0%

Tin 100.0% 0.0%

Mercury 100.0% 0.0%

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• Electrowinning

• Cementation

• Gaseous Precipitation


• Gaseous Precipitation

• Chemical Precipitation

• Solvent Extraction

• Ion Exchange

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Electrowinning of Alkaline Sulfide

Leach Solution for Gold Recovery

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ANALYSIS OF ENARGITE CONCENTRATE

Table 1. Concentrate Analysis.

Cu, % Fe, % As, % Au, o/T SiO2, % Ca, % Al, %


Application

2

15.83 16.59 0.87 0.10 20.11 1.21 3.56

X-ray diffraction analysis and MLA was undertaken to characterize the concentrate. The major phases present are Enargite, Cu3AsS4 and Quartz, SiO2.

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Alkaline Sulfide Hydrometallurgy Enargite

Application

Alkaline Sulfide Leaching Conditions.

Slurry Solids Content = 400 g/L

Maximum Temperature = 103o C

NaOH Concentration = 25.0 g/LNaOH Concentration = 25.0 g/L

S-2 Concentration = 60.0 g/L

Total Time = 12 Hours

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Application

Alkaline Sulfide Timed As Recoveries.

Time, Hr % As Leached

0 0.0

1 64.3

2 84.3

4 91.2

6 91.6

12 91.6

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Application

Mass Distribution of Alkaline

Sulfide Leach Products

Cu , % As , % Au, %

Solution 0.0 91.6 32.6 Solution 0.0 91.6 32.6

Residue 100.0 8.4 67.4

Mass Reduction = 0.41 %

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As, Au and Cu Leaching 400 g/L Solids, 103 C & 6 Ho urs.

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0P

erce

nt

0.0

10.0

20.0

30.0

10.0 20.0 30.0 40.0 50.0 60.0 70.0

S-2 Concentration (g/L)

SOLUTION Cu% SOLUTION As% SOLUTION Au% RESIDUE Cu% RESIDUE As% RESIDUE Au%

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ApplicationLocked Cycle Leaching Results

Slurry Solids = 400 g/L

Leach Temperature = 100O C

NaOH = 25.0 g/L

S-2 = 60.0 g/L

Reaction Time = 4.0 Hrs

Locked Test Cycles = 7

Final Concentrate Weight Gain = 8.05 %Final Concentrate Weight Gain = 8.05 %

Reagent Consumption

NaOH = 17.65 Kg/Dry Tonne Concentrate

Na2S = 73.2 Kg/Tonne Dry Concentrate

Copper Recovered to Liquid = 0.00 %

Arsenic Recovered to Liquid = 93.72 %

Antimony Recovered to Liquid = 50.15 %

Silver Recovered to Liquid = 0.00 %

Gold Recovered to Liquid = 22.98 %

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Application

Final Locked Cycle Leached Concentrate Analysis.

Cu, % Fe, % As, % Au, o/T SiO , % Ca, % Al, % Cu, % Fe, % As, % Au, o/T SiO2, % Ca, % Al, %

16.54 16.61 0.01 0.07 20.11 1.21 3.56

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ALKALINE SULFIDE ENARGITE FLOWSHEET

Enargite Concentrate

ASL

Leaching

Thickener

Liquid

Recycle 95 %Solid

Drum Filter

Drum Filter

Solids to Smelter

Liquid

LiquidLiquid

SolidSolid

Solid

Tank

Autoclave

Gold

Recovery

Bleedstream 5 %

Tails Treatment

Tank

Iron Salts

Filter Press

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THE INDUSTRIAL ALKALINE SULFIDE

HYDROMETALLURGICAL

TREATMENT OF MERCURY BEARING

ANTIMONY ORES AND CONCENTRATESANTIMONY ORES AND CONCENTRATES

Corby G. Anderson

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Mercury is commonly found in association with antimony ores.

Cinnabar, HgS

Livingstonite, HgSb4S7

Tetrahedrite, Cu12Sb4S13

Stibnite, Sb SStibnite, Sb2S3

Found in Algeria, Mexico, USSR, Slovakia, Tajikistan, China and North America.

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Alkaline Sulfide

Hydrometallurgy Fundamentals

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The alkaline sulfide system is a very selective

lixiviant for antimony, arsenic, tin, gold and

mercury in lieu of other metals .

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Na2S + Sb2S3 � 2NaSbS2

NaSbS2 + Na2S � Na3SbS3

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Na2S + HgS � + Na2HgS2

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0

1

2

HgS

HgO

Hg2SO4

Hg(l)

HgSO4(a)

Hg2+

S

SO42-HSO4

-volts)

Eh-pH Diagram for Mercury in the Alkaline Sulfide System.

-2

-1

0

0 2 4 6 8 10 12 14

HgS

Hg(l)

HgS22-

HS-H2S(a) S2-

pH

Eh (v

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Na2S + SnS2 � + Na2SnS3

3Na S + As S � 2Na AsS3Na2S + As2S3 � 2Na3AsS3

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4So + 6NaOH � 2Na2S + Na2S2O3 + 3H2O

(X-1) So + Na S � Na S (where X= 2 to 5) (X-1) So + Na2S � Na2SX (where X= 2 to 5)

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Gold lixiviation in the alkaline sulfide system

postulated to be the result of oxidation by

polysulfide and complexation as a sulfide .

Leaching may occur as;

Au + S AuS + e-Auo + S5-2 � AuS5

- + e-

Recovered by EW, cementation, chemical or

gaseous precipitation, IX, SX.

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Na2SX + (X-1)Na3SbS3 � (X-1)Na3SbS4 + Na2S

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Electrowinning of Antimony

The primary anode reactions are;

4OH- �� 4e- + 2H2O + O2

S-2 �� 2e- + SO

The primary cathode reaction is;

SbS3 -3 + 3e- �� SbO + 3S-2

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Sodium Hydroxy Antimonate Production

2H2O + 2NaOH + Na3SbS4 + 4O2 �� NaSb(OH)6 + 2Na2S2O3

2Na2HgS2 + H2O + O2 �� 2HgS + Na2S2O3 + 2NaOH

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Applications to Antimony Ores

Slovakia

Tajikistan

Chile

Peru

Mexico

North America

Australia

Sweden ????

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Roznava Tetrahedrite Concentrate.

Sb, %, As, % Hg, %, Cu, %, Fe, % Ag, ppm Au, ppm TS, %

17.3 1.85 0.55 26.1 12.4 6,400 2.0 22.0

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Alkaline Sulfide Leach Testing Conditions.

Leach Time = 12 Hr.

Roznava Concentrate = 100 g/L

Leach Temperature = 105O C

Sulfur Addition = 20 g/L

Sodium Hydroxide = 35 g/L

Sb Leached = 95.0 % As Leached = 60.0 %

Hg Leached =95.0 % Au Leached = 20.0 %

Cu Leached = 0.0 % Ag Leached = 0.0 %

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Roznava Concentrate After Alkaline Sulfide Leaching.

Sb, %, As, % Hg, %, Cu, %, Fe, % Ag, ppm Au, ppm TS, %

0.87 0.74 0.03 26.1 12.4 6,400 1.6 22.0

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Proposed Slovakian Plant Technology.

Alkaline sulfide leaching.

Solution purification by selective crystallization.

Mercury removal along with waste antimonate production.

Mercury selectively leached, stabilized, encapsulated and stored.

Alkaline sulfide lixiviated gold recovered by IX.

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Slovakian Alkaline Sulfide Hydrometallurgical Economics.

There was some existing infrastructure.

Local costs for reagents, manpower and utilities were used.

Mercury is separated, stabilized and locally stored.

The plant produces 1,000 tons of high grade antimony per year by

electrowinning from Roznava mercury bearing tetrahedriteelectrowinning from Roznava mercury bearing tetrahedrite

concentrates.

The capital costs include installed equipment, piping, instrumentation

and engineering.

Copper concentrates suitable for smelter treatment will be produced.

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Estimated Unit Operating Costs.

Sulfur = $ 0.025 USD/lb EW Sb produced

Caustic = $ 0.20 USD/lb EW Sb produced

Steam = $ 0.20 USD/lb EW Sb produced

Electricity = $ 0.20 USD/lb EW Sb produced

Oxygen = $ 0.10 USD/lb EW Sb produced

Waste treatment = $ 0.025 EW USD/lb Sb producedWaste treatment = $ 0.025 EW USD/lb Sb produced

Wages = $ 0.10 USD/lb EW Sb produced

Maintenance = $ 0.05 USD/lb EW Sb produced

Total Operating Cost = $ 0.90 USD /lb EW Sb produced

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Estimated Unit Capital Costs.

Leaching and Solid Liquid Separation = $ 3,500,000.00 USD

Solution Purification = $ 1,500,000.00 USD

Electrowinning = $ 2,500,000.00 USD

Waste Treatment = $ 1,000,000.00 USD

First Fills and Working Capital = $1,500,000.00 USDFirst Fills and Working Capital = $1,500,000.00 USD

Total Capital Cost = $ 10,000,000.00 USD

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Alkaline Sulfide Recovery Of Gold Utilizing

Nitrogen Species Catalyzed Pressure

Leaching

Dr. Corby G. Anderson

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Gold Concentrate Treated With Complete NSC Sulfide Oxidation

Gold = 35 g/T Iron = 25.0% Arsenic = 6.31% Total Sulfur = 24.0%

This Kazakh arsenopyrite concentrate also This Kazakh arsenopyrite concentrate also has high carbon leading to preg robbing.

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Nitrogen Species Catalyzed Complete Sulfide Oxidation Leach Conditions.

Initial Free Sulfuric Acid = 20 g/LReactor Working Pressure = 975 kPag

.

Reactor Working Pressure = 975 kPagSlurry Solids Content = 100 g/LSolids Size = 80% minus 10 micronMaximum Temperature = 170o C Nitrogen Species Concentration = 2.0 g/LReaction Time = 45 minutes

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CIL Gold Recovery From Complete NSC Sulfide Oxidation.

CIL Au recovery = 94.2%

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Gold Concentrate Treated With Partial NSC Sulfide Oxidation

Gold = 35 g/T Iron = 25.0% Arsenic = 6.31% Total Sulfur = 24.0%Arsenic = 6.31% Total Sulfur = 24.0%

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Nitrogen Species Catalyzed Partial Sulfide Oxidation Leach Conditions.

Initial Free Sulfuric Acid = 50 g/LReactor Working Pressure = 620 kPagReactor Working Pressure = 620 kPagSlurry Solids Content = 100 g/LSolids Size = 80% minus 10 micronMaximum Temperature = 125o C Nitrogen Species Concentration = 2.0 g/LReaction Time = 30 minutes

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Alkaline Sulfide Recovery With Partial NSC Sulfide Oxidation.

Alkaline Sulfide Au recovery = 93.3%

No cyanide is used to avoid preg robbing !!

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Conclusion

Hydrometallurgy is very effective in the treatment of complex copper concentrates which contain impurities such as arsenic, antimony and mercury.

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Thank you for this opportunity !

I look forward to my next visit to Peru.

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The Effective Hydrometallurgical

Treatment of Arsenic Bearing Copper

Ores and Concentrates

Eur Ing Dr. Corby G. Anderson QP CEng FIMMM FIChemE


Kroll Institute for Extractive Metallurgy


Golden, Colorado USA 80401

corby anderson

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