MaxR Technology for Impurity Removal[1]

8/13/2019 MaxR Technology for Impurity Removal[1]

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MMAXAXRR

PRECIPITATIONPRECIPITATIONTREATMENT TECHNOLOGYTREATMENT TECHNOLOGY

for HYDROMETALLURGYfor HYDROMETALLURGY

MMMA COLLOQUIM

24 August 2007

Footnote:This presentation is based on information provided in the MaxR Treatment Process brochure. First is the two basic

types of applications:impurities removal used at European Nickels Caldag project in Turkey designed by Aker Kvaerner in Brisbane

Effluent discharge used for acid mine water at Iron Mountain in California, USA and recently by Cameco a uraniumproducer in Saskatchewan, Canada at Rabbit Lake and Key Lake. Using MaxR treatment was the only way toremove uranium, selenium and molybdenum to g/l concentrations before discharge into the water shed.


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HYDROMETALLURGYHYDROMETALLURGY Goal is to dissolve metals in ore or concentrate:

Desir ed metalsCo, Cu, Ni, U and,

Undesired metalsAl, Fe, Mg, Mn, etc.

Impurities removal is required to cont rol so lub i l i tyor

meet water discharge requir emen ts. MaxRTechn ology c ontro ls p art ic le size

dist r ib ut ion and encapsulates elem ents.

Footnote:This sl ide identifies that sulfuric acid as a l ixivant dissolves both desirable and undesi rable metals and the

undesirable metals must be removed. There is always excess acid that creates gypsum in addition to the sulfatesof the metallic sal ts.

Controlling soluble impurities concentrates is necessary to continue to dissolve more metals in the recycle streamand if solvent extraction is used to remove iron and other metals that could contaminate the product metals.


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Undesired Metal Removal forUndesired Metal Removal for

Solubi l i ty Contro lSolubi l i ty Con tro l Soluble concentrations measured as (g/l),

Solubility is decreased by increasing pH with lime or

limestone,

Pregnant liquor will contain soluble desired metalsthat must be recovered by filtrating and washing the

precipitated solids,

Footnote:It is important to note that for solubility control the dissolved metals are measured in g/l or more than three orders

of magnitude in acid mine water of waste stream to be discharged into water sheds.It is also important to note that value dissolved metals must remains in solution, therefore all excess acid and iron

will be removed at pH ~4. This is where most gypsum is precipitated and where the MaxR technology is mostvalued as increasing the particle size distribution increases both gravity sedimentation and filtration allowing theuse of HBF with washing.


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Undesired Metal Removal to MeetUndesired Metal Removal to Meet

Discharge Requ irementsDischarge Requ irements

Soluble concentrations measured as (mg/l) in

feed streams and (g/l) in discharge streams,

pH >8 will be required to precipitate all metals

Two stages of precipitation is required.

Footnote:Discharge requirements are at mg/l and or g/l so not to pollute the environment. In this case the pH is typical ly

increased to >8 to precipitate all contaminates. Depending on the mixture of metals two stages of precipitation mybe required. This is the case at the two Cameco installations. The encapsulation of toxic metals with gypsum was

the only way to prevent re-dissolving or the only way to capture the suspended solids.


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Typ ical FlowsheetsTyp ical Flows heets Conventional Solids Precipitation Once through

Nucleation or finest particles

Conventional Solids Precipitation with Recycle

Multiple passes

Partial nucleation and particle growth

MAXR

Solids Precipitation

Multiple passes

Minimal nucleation and maximum particle growth or largest

particles

Footnote:Discharge requirements are at mg/l and or g/l so not to pollute the environment. In this case the pH is typical ly

increased to >8 to precipitate all contaminates. Depending on the mixture of metals two stages of precipitation mybe required. This is the case at the two Cameco installations. The encapsulation of toxic metals with gypsum was

the only way to prevent re-dissolving or the only way to capture the suspended solids.


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Conventional Sol ids Prec ipi tat ionConvent ional Sol ids Precip i tation

Footnote:This is the conventional once through flowsheet typical ly with 3-5 reactions tanks depending on scale formation and operating

temperature. Kinetics are slower with lower temperature and limestone as it takes time for large pieces of limestone to dissolveore react with sulfates.

In many cases the filtration must be via pressure filtration and vacuum filtration is typically much


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Convent ionalConvent ional Sol idsSol idsPrecip itat ion withPrecip itat io n withRecycleRecycle

Footnote:This shows the

typical recyclescheme with a wide

range of recyclerates. Few use aflash mix tank to

coat the suspended

solids particles.Sometime this can

produce suspendedsolids that can be

filtered on a HBF atrates of 50-100kg/h/m2.


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MMAXAXRR

Solids PrecipitationSolids Precipitation

O2 (Air)

Ca(OH)2 or

CaCO3

Solids Recycle

O/F

Diluted

Flocculant

Neutralization and Precipitation Tanks

pH 3.5-4.5Thickener

Filter Cake

Horizontal Belt Filter

Wash Wa ter

Filtrate

2ndStage Water

Solids

Contact

Tank

Raffinate or

Pregnant Liquor

Recycle or

to Recovery

Footnote:MaxR will typically produce

filtration rate of >150-250kg/h/m2. Recycle ratios can

be 2-20 times suspendedsolid production depending onconcentrations.


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Precipi tat ion Process VariablesPrecipi tation Process Variables

Solution Composition & Concentrations

Free Acid:Fe Ratio

Amount of gypsum

Fe+2:Fe+3 Ratio

Amount of air

Neutralization Chemicals

CaO, CaCO3, NaOH, Na2CO3, Quality

pH and Redox potential

Residence Time Mixing System Design

Recycle Rate and Type

Footnote:These are general process variable.

Obvious ly the composition and concentrations of soluble metals is very importantGreater free acid and less soluble Fe makes much gypsum and easy precipitation. However minimizing excess

acid saves operating cost but make S/L separation difficult. The lower the excess acid the more dramatic MaxRFerrous oxidation to ferric defines the oxygen needLimestone generates CO2 and must be striped with air or carbonic acid will buffer the pH. Pour quality limestone

can act as a filter aid.Residence time is most in fluenced by temperature and limestone particle size.The mixing system must be properly designed to dissolve oxygen and maintain solids suspension


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Typical Impu r i t ies Chem istryTypical Impu r i t ies Chem istry

Footnote:This is the chemistry and the key point is defining the quantity of gypsum produced. Notice Fe and Al produce

gypsum and also are trivalent atoms that settle slowly.


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CPSCPSTank 1Tank 1

Before React ionsBefore React ions

Footnote:This shows a conventional precipitation with soluble metal

salts and reagents before reaction. Each reaction will formone single small compound that are very small and difficult

to separate.


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CPSCPSTank 2Tank 2

Partial ly ReactedPartial ly Reacted

Footnote:This shows the composition based on the chemical

equations identified earlier. Al, Mg, Mn are slowerto precipitate that Fe and sulfuric acid. The

reactions are only partially complete.


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CPSCPSTank 3 or 4?Tank 3 or 4?

React ion s Comp lete Nuclear Part ic lesReact ion s Comp lete Nuclear Part ic les

Footnote:This is completed reactions although Al, Mg, and Mn will still

remain soluble if pH is 4.0 for Fe and acid removal.


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MMAXAXRR 11s ts tRecy cle Tank 1Recycle Tank 1

Before React ionsBefore React ionsFootnote:This shows what happens

on the first recycle ofsolids before the

chemistry kicks in. Thelimestone coats thesuspended solids.


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MMAXAXRR11s ts tRecy cle Tank 2Recy cle Tank 2

Before React ionsBefore React ionsFootnote:This shows the precipitation of

metals and gypsum on thesuspended solids significantly

increasing particle size. Thereare always some individualparticles generated.


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MMAXAXRR 22ndndRecy cle Tank 1Recy cle Tank 1


CaCO3

CaCO3

CaCO3

CaSO4

Al(OH)3

CaSO4Fe(OH)3

CaCO3

CaCO3

CaCO3CaCO3

CaCO3

CaSO4

CaSO4

Al(OH)3

Fe(OH)3

CaCO3

CaCO3 CaCO3CaCO3

CaSO4

Fe(OH)3Al(OH)3

CaSO4

CaCO3

H2SO4

H2SO4

H2SO4

Fe2(SO4)3

Fe2(SO4)3

MgSO4

MnSO4

FeSO4

Al2(SO4)3

O2

FeS

O4

Insoluble Precipitates

Reagents

Soluble Impurities

Footnote:This shows the second recycle

with agglomerated particlesbeing coated again by the

limestone and the samesoluble concentration ofdissolved metals. The particle

size has increased and thesurface area for reaction hasincreased.


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MMAXAXRR 33rdrdRecy cle Tank 1Recy cle Tank 1


CaCO3

CaCO3

CaCO3

CaCO3

CaCO3

CaCO3

CaCO3

CaCO3

CaSO4

CaSO4

Al(OH)3Fe(OH)3

CaSO4

Fe(OH)3

MnOH

CaSO4

CaCO3CaSO4

CaSO4

Al(OH)3

CaSO4

CaSO4

Fe(OH)3

Al(OH)3

Fe(OH)3

CaSO4

CaCO3

CaCO3

CaCO3

CaCO3

O2

O2

H2SO4

H2SO4

H2SO4

Fe2(SO4)3

Fe2(SO4)3

MgSO4

MnSO4

Al2(SO4)3

FeSO4

O2

FeS

O4

Insoluble Precipitates

Reagents

Soluble Impurities

Footnote:This show the results

on the third recycle ofsolids. There are

many large particlesthat get bigger. Theselarge particles can be

flocculated easily andfilter very fast.


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Advantages Due toAdvantages Due to MMAXAXRRTechnologyTechnology

Larger particles

Denser particles

Heterogeneous precipitates with gypsum as ballast

Gypsum encapsulated dilute metals

Increased reaction kinetics

Improved solid/liquid separation rates

Footnote:This is a summary of the benefits.

Increased the particle size dis tribution make S/L separation easier.The particles are actually denser with a greater bulk density created by the layered particle growth and the fact that

the particle are heterogeneous in composition with gypsum compressing the Al and Fe hydroxides.The sketches showed how the encapsulation process occurs

A greater suspended solids concentration and resulting surface area increases the reaction kinetics


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MaxRMaxRIron Mountain Acid Mine DrainageIron Mountain Acid Mine Drainage

85.3 m Diameter Thickener/Clarifier

Footnote:This shows the faci lity at Iron

Mountain, located in California,USA. The Environmental

Protection Agency mandated

the use of the MaxR technologyfor this project to reduce the

sludge volume that wasgenerated by the process. Thelife of the disposal site was

extended by nearly 2X usingthis technology.

EIMCO s upplied a 280-ftdiameter thickener and

upgraded the aeration andtreatment system.


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ACID MINE WATER TREATMENTACID MINE WATER TREATMENT

IRON MOUNTAIN, CAL IFORN IA, USAIRON MOUNTAIN, CAL IFORN IA, USACOMPARISONCOMPARISON

Conventional Solids

Precipitation 'CSP.MaxR

Technology

Reactor Effluent Solids, wt% 6 20

Thickener Underflow Solids, wt% 15-20 40-60

Thickener Unit Area, m2/t/d 6.3-8.1 0.8-1.3

Ultimate Solids in Drying Pond, wt% 35-40 65-70

Vacuum Filtration Rate, kg/hr/m2 15-25 318-440

Vacuum Filter Cake Solids, wt% 40-50 75

Treatment pH 9-9.5 7.9-8.1


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MaxRMaxRReference Ins tal lat ion sReference Ins tal lat ionsReference

Year

I nstalled Application Location

Equipment

Size Comments

INCO Argentia 2005 Fe RemovalNewfoundland,

Canada

(1) 2 m

ThickenerDemonstration plant

Arco MontanaResources

2003Mine WaterInfiltration

Montana, USA1-150 ft & 1-

175 ftThickener

Iluka Resources 2002TiO2acid

NeutralizationVirginia, USA

(1) 35 ftThickener

Classic Flowsheetwith (1) Reactor

Occidental Chemical 2001NaOH-Cl2Brine

TreatmentLouisiana,

USA(1) 70 HRB

HRB w/externalrecycle

Westlake Chemical 2001NaOH-Cl2Brine

Treatment

Kentucky,

USA(1) 65 HRB

HRB w/external

recycle

Vulcan Chemical 2000NaOH-Cl2Brine

TreatmentLouisiana,

USA(1) 100 ft

HRB

HRB w/externalrecycle, OTG

polishing

Homer City

Generation

2000Electric Power

Plant Wastewater

Pennsylvania,

USA

System

Iron Mountain 1997Acid MineDrainage

California,USA

(1) 280 ftThickener

Classic Flowsheetwith (2) Reactors

Footnote:This is an installation list that can or may not be used at your discrestion.


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MaxRMaxRReference Instal lat io nsReference Ins tal lat ions

ReferenceYear

I nstalledApplication Location

Equipment

SizeComments

BaoSteel 1997Acid/AlkaliWastewater

Shanghai,China PRC

(2) 15 mMRCs

MRC w/externalrecycle,

(1) Reactor

BaoSteel 1997Chromium

WastewaterShanghai,China PRC

(2) 10 mMRCs

MRC w/externalrecycle,

(1) ReactorNational FertilizerPublic Company

1997Fertilizer

WastewaterThailand

(2) 15 mThickeners

Barrick Goldstrike 1997Mine WaterInfiltration

Nevada, USA(2) 280 ft

Thickeners

SCM Chemicals (II) 1996 Acid Wastewater Ohio, USA(1) 12.3 mThickener

SCM Chemicals (I) 1995 Acid Wastewater Ohio, USA(1) Drum

Filter

Kennecott Copper /Rio Tinto

1994 Fe Removal Utah, USA

ICI Americas 1992 HF WastewaterLouisiana,

USA

(1) 10 mHRB, (1)

Delta Stak


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MaxRMaxRReference Instal lat io nsReference Ins tal lat ions

ReferenceYear

InstalledApplication Location

Equipment

SizeComments

Copebras (Anglo-

American Group) 1991

Calcium

Phosphate

Cubatao, Sao

Paulo, Brazil

(2) 22 m

HRBs

2-StagePrecipitation

HRB w/externalrecycle,

(1) Reactor ea.

Morton Thiokal 1989Chemical

WastewaterMississippi,

USA

(1) 11 mThickener, (2)

30 m HRB,(2) 7.5 m2 E-

belt Filters

Kikkoman 1988 Food BrineTreatment

Wisconsin,USA

(1) 12 ft HRB,GMF

Molycorp 1984 PbS RefineryCalifornia,

USA


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MaxRMaxRCurren t Pro jectsCurren t Pro jects

Project Year Application Location

Caldag Nickel 2006Fe & Al Removal from

NiSO4 Turkey

Key Lake 2007Se, Mo, Fe Removal from

UCanada

Rabbit Lake 2007Se, Mo, Fe Renoval from

UCanada

Vermelho 2008 Fe Renoval from Ni Brazi l

Tenke Fungurume 2006 Fe Removal from CuDemocratic Republico

of Congo

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MaxR Technology for Impurity Removal[1]