Transcript Document

There and Back Again 2.5
Who Did What in Solvent Extraction
A Demonstrated & Proven Technology for
Uranium Recovery from Phosphoric Acid
Vaughn Astley
Regis Stana
Symphos 2013
Agadir, Morocco
6th to 10th May, 2013
Our Backgrounds and
Experience
Regis & I Have
Background and Experience
– I had Technical and Development Responsibility
for Freeport Agrico Uranium Extraction Plants at
Uncle Sam and Faustina from 1982 to 1995
– Rege with Westinghouse R&D, Worked on Several
Processes for Recovery of Uranium from WPA Acid
and other Sources (Including IX and Membranes)
…..Three Years at Operating Plant
– Hired By IMC in 1981 to “Fix” their Uranium
Recovery Plants
• One Complete Plant at New Wales
• Two First Cycles at Two CF Plants)
.
Regis & I Have
Background and Experience
– In 1993 IMC and Freeport Agrico Merged Giving
Rege and I Access to Each Others Uranium
Recovery Experience.
•
•
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.
What
What
What
What
was done that did not work.
did work.
we would not do again.
would a better design encompass.
– Extensive Performance and Cost Data for All 4
Plants over their Operational Years
– Contacts With The People that Ran These Facilities
– We are Concerned About Loss of This Memory.
The Three Waves
1. Started in 1950s, ended early 1960s –
Emphasis on Military Stockpiling
2. Started late 1970s, ended 1990s –
Nuclear Power
3. 2010s? – Nuclear Renaissance/ Era of
Resource Conservation and
Sustainability, Carbon Dioxide Mitigation
4. Renewed Interest in Uranium Supply.
.
P2O5
A Potential Major Source for Uranium
• Phosphate Deposits Contain Uranium
– Nature and Value of Deposits are in a Phase of
Extreme Transition
• Uranium Recovery is a Well-Tested Additional
Opportunity in Phosphoric Acid Production
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Range: 0.1-7 Kg/Tonne of P2O5
Typically: 0.3-0.6 Kg U per Tonne P2O5
Price: Volatile, but in 2007, U3O8 Reached $300/KG
Currently About $90/Kg on Spot Market and $150/Kg
for Some Long Term Contracts
.
History of Uranium Recovery from
Phosphoric Acid:
First Wave
• First Plant was Built in 1952 in Joilet Illinois.
It Precipitated the Uranium as a Phosphate
• Two Plants were Built in 1955 & 1957 in
Florida. These Used a Solvent Extraction
Process (Octyl Pyro Phosphoric Acid)
• All Three Plants Operated until the Early 60s,
when the Low Cost Production of Uranium
from Western Mines Depressed the Price
.
History of Uranium Recovery from
Phosphoric Acid
Second Wave
• The Price of Uranium Increased Dramatically
in the 1970s
• Eight new Plants were Built in the United
States for the Recovery of Uranium From
Phosphoric Acid
• Six were in Florida and Two were in Louisiana
• Plants were also Built in Canada, Spain,
Israel, Belgium, Iran, Iraq, China and Taiwan
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Westinghouse Plant at Farmland Industries
UR Plant Area 1 Hectare
Refinery Building
First Stage Mixer Settlers
.
Control Room
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IMC Plant at New Wales
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IMC Plant at New Wales
UR Plant Area 2.5 Hectares
Clarifiers and Carbon Columns
First Stage Mixer Settlers
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Uranium Recovered From
Phosphoric Acid in the USA
1.5
Millions 1
of Kg of
U3O8 0.5
0
1978 1982 1986 1990 1994 1998
Total U3O8 Recovered Approximately 20 Million Kgs
.
Flow Sheets of Recent U.S.A. Plants
Incoming
Acid Pretreatment
30% Acid
Pregnant
Solvent
Second Cycle
Extraction
First Cycle Extraction
Raffinate
Post Treatment
Barren
Solvent
First Cycle Strip
Loaded
Strip Acid
Strip Acid
Pregnant
Solvent
Second Cycle
Strip
Loaded
Strip Solution
.
Precipitation of Uranium,
Drying, and Calcining
Ship to
Converter
Flow Sheets of Recent U.S.A. Plants
• All Plants Extracted Uranium from Acid
Produced by Dihydrate Processes (27-28%
P2O5 Plus 1.5-3% Sulfate)
• All Acids were Produced from Central Florida
Rock
• U3O8 Content of All Acids was About 0.5
Kg/Tonne P2O5
• All Used a Solvent Extraction Process
• The Processes were Developed by
Westinghouse, IMC (3 Plants), Uranium
Recovery Corp., Freeport (2 Plants), and
. Gardinier
Flow Sheets of Recent U.S.A. Plants
• Acid Pretreatment
– Westinghouse Flash Cooled to 38 oC,
Clarified with Flocculent and Reheated to
40 oC
– IMC Used Spiral Coolers to Cool 49 oC,
Added Clay and Flocculent Before
Clarification, then Passed Acid Through
Carbon Columns (Abandoned after 6
Years)
.
Flow Sheets of Recent U.S.A. Plants
• Pretreatment (Contd)
– URC Did Not Cool, and Clarified Only
– Freeport Did Not Cool, but Added a
Flocculent and Clarified
– Gardinier Cooled the Acid to 32 oC Using 2
Stage Flash coolers and Clarified the Acid.
The Acid was Reduced with Scrap Iron and
then Filtered Using Pressure Leaf Filters
.
Flow Sheets of Recent U.S.A. Plants
• Oxidation Change
– Westinghouse Used Nitric Acid to Oxidize Acid
(and Uranium)
– IMC Used Hydrogen Peroxide (Later Changed to
Oxygen) to Oxidize Acid (and Uranium)
– URC Used Ferro Silicon to Reduce Acid (and
Uranium)
– Freeport Used Oxygen to Oxidize Acid (and
Uranium)
.
Flow Sheets of Recent U.S.A. Plants
• Uranium Extractant Solvents
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–
–
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Westinghouse Used DEPA/TOPO
IMC Used DEPA/TOPO
URC Used Octyl Pyro Phosphoric Acid
Freeport Used DEPA/TOPO
• Mixer Settler Design
.
– Westinghouse Used Holms and Narver Low Profile
Pumper/Mixers/Rectangular Settlers
– IMC Used Circular M/S
– URC Used Deep Cone Bottom Tank M/S
– Freeport Used Low Profile Pumper/Mixers & Racked
Rectangular M/S
Flow Sheets of Recent U.S.A. Plants
• CRUD
– When Any Organic Solvent is Mixed with Wet Process
Phosphoric Acid, a Third Interfacial Phase is Formed that is
Termed “Crud” or “Gunk”.
– It Must be Removed from the Settlers or it will Interfere with
the Performance of the Settler
– “Crud” Contains About 50% Solvent, so the Solvent Must be
Recovered
• Crud Removal
.
– Westinghouse Continuously Over Flowed Crud from First
Settler and Intermittently Pumped from the Rest
– IMC Pumped Crud From All Circular Settlers
– URC Batch Overflowed Crud From Settlers
– Freeport Used Interface Drag Devices to Pull Crud Out of
Settlers
Flow Sheets of Recent U.S.A. Plants
• Crud Processing
– Westinghouse Used Centrifuge (Abandoned) and
Pre Coat Vacuum Drum Filter
– IMC Initially Used Plate and Frame Filters and
then Pre Coat Vacuum Drum Filter
– URC Used Centrifuges and Pre Coat Vacuum Drum
Filter
– Freeport Used Chemical Treatment, a Patented
Centrifuge Separation, and a Crud Maker System
.
Flow Sheets of Recent U.S.A. Plants
• First Cycle Stripping
– Westinghouse Used 27% P2O5 Acid Reduced with
Scrap Iron Plus Powdered Iron Within Stages
– IMC Used 31% P2O5 Acid Plus Sulfuric with Iron
Ball Towers for Each Stage for Reduction
– URC Used 40% P2O5 Acid Plus Peroxide
– Freeport Used a Boosted Strength 31% P2O5 Acid
With Iron Ball Towers for Each Stage for
Reduction
– Gardinier Stripped the Solvent Using 15% HF
.
Flow Sheets of Recent U.S.A. Plants
• Second Cycle Oxidation
– Westinghouse Used Nitric Acid to Oxidize Acid
(and Uranium)
– IMC Used Hydrogen Peroxide (Later Changed to
Oxygen) to Oxidize Acid (and Uranium)
– URC First Cycle Acid Was Already Oxidized
– Freeport Used Oxygen to Oxidize Acid (and
Uranium)
– The Gardinier Process Did not Require Oxidation
.
Flow Sheets of Recent U.S.A. Plants
• Second Cycles
– All Plants (Except Gardinier) Used DEPA/TOPO in
Second Cycle with Rectangular Mixer Settlers for
Extraction and Strip
– All Used Ammonium Carbonate for Stripping
– Each Precipitated the Uranium as an Ammonium
Compound
– All Calcined to a Black Oxide and Shipped in 55
Gallon Drums
.
Operating Experience with Plants
• Westinghouse Plant Operated With 98+ %
On Stream Factor and 92+% U3O8 Recovery
– Turn Around After 2 Years and Down for
Mechanical Problems Only
– Organic Advance was Being Increased to Increase
Recovery to 96% when Price of Uranium Dropped
and Plant Closed
• IMC Plants Operated at 92% On Stream
Factor and 96% U3O8 Recovery (Down
– Weekly for Line Scrubs and Yearly Turn Around)
.
Operating Experience with Plants
• URC Plant Operated at Less Than 60% On
Stream Factor and Less than 80% Recovery
(Lots of Mechanical Problems and Problems
with Crud Build Up)
• Freeport Plants Operated at 92% On Stream
Factor and 95% U3O8 Recovery (Down
Weekly for Line Scrubs and Yearly Turn
Around)
• The Gardinier Plant Obtained About 90%
Recovery
.
Operating Experience with Plants
• Westinghouse Plant Produced Over 137,000 Kg/Yr
U3O8.
• IMC New Wales Plant Produced as Much as 591,000
Kg/Yr U3O8. CF Plant City Module Produced as Much
as 409,000 Kg/Yr U3O8. One CF Plant Closed Down
After Less than 3 Years of Operation
• URC Plant Produced About 45,000 Kg/Yr U3O8.
• Freeport Plants Produced as Much as 482,000 Kg/Yr
U3O8. (Combined)
.
Plant / Design
Gardinier
IMC
Spiral coolers
cool - 49oC
Clay
/flocculant
added before
clarification
Colour
removal activated C
Oxidised with
H2O2. Later O2
DEHPA/TOPO
Pretreatment
Cooling
Solids
Removal
No cooling
Flocculant added
before
clarification
2-stage flash
cooling - 32oC
Filtered using
pressure leaf
filters
Further
Pretreatment
None
None
Oxidation
State Change
First Cycle
Solvent
Oxidised with
oxygen
DEHPA/TOPO
Mixer Settler
Design
Low profile
rectangular
pumper-mixer
settlers
31% P2O5 acid
plus iron
Reduced
with scrap Fe
Octyl pyrophosphoric
acid (OPPA)
Rectangular
pumper-mixer
settlers
First Cycle
Strip Solution
Second Cycle
Oxidation
State Change
Second Cycle
Solvent
Uranium
Precipitate
Form
.
Freeport
Circular mixer
settlers
Oxidised with
oxygen
15% HF
precipitated U
as green salt
Dissolved in
nitric acid
DEHPA/TOPO
TBP
31% P2O5 acid
plus sulphuric
acid and iron
Oxidised with
H2O2. Later
used oxygen
DEHPA/TOPO
Ammonium
diuranate
Ammonium
diuranate
Uranyl
peroxide
Uranium
Recovery Corp.
No cooling
Westinghouse
Flash cool - 38oC
Flocculant added
before
clarification
Flocculant added
before
clarification
None
None
Reduced using
ferro-silicon
Octyl pyrophosphoric acid
(OPPA)
Deep-cone
bottom settlers
Oxidised using
nitric acid
DEHPA/TOPO
Low profile
rectangular
pumper-mixer
settlers
27% P2O5 acid
plus iron
40% P2O5 acid
plus hydrogen
peroxide
No oxidation
change required
DEHPA/TOPO
DEHPA/TOPO
Ammonium
uranyl
tricarbonate
Ammonium
uranyl
tricarbonate
Oxidised using
nitric acid
Economics of Previous Plants
• Westinghouse Total Capital Cost was Less Than
$20,000,000.
(About 20% of the Equipment was Not Used or
Eliminated)
• IMC Total Capital Cost was About $200,000,000 (3
Plants)
(At Least 30% of the Equipment was Eventually
Eliminated)
• URC Total Capital Cost was About $30,000,000
• Freeport Total Capital Cost was $40,000,000 for
Uncle Sam and $30,000,000 for Faustina
(About 10% of the Equipment was Eventually
Eliminated)
• The Gardinier Capital Cost was About $25,000,000
.
Economics of Previous Plants
• Westinghouse Total Cash Cost (Including Royalty,
Cost of Acid Dilution, Losses and Reheat) was About
$37/Kg U3O8 ($24/Kg w/o Royalty etc)
• IMC (New Wales) Cash Operating Costs (No Royalty,
Dilution, Reheat or Loss Cost) was About $24/Kg
U3O8
• URC Total Cash Cost (Including Royalty, Cost of Acid
Dilution and Acid Losses) was About $100/Kg U3O8
(Low Throughput and Operating Factor)
• Freeport Cash Operating Costs (No Royalty, Dilution,
Reheat or Loss Cost) was About $26/Kg U3O8
• Gardinier Cash Operating Cost was About $40/Kg
U3O8
.
Economics of Previous Plants
• Operating Labor Requirements
• Flow Sheet A Required 5 Shift Supervisors, 4
Chief Operators, and 2 Operators.
• Flow Sheet B Required 3 Shift Supervisors, 4
Chief Operators, 5 Operators and 2 Laborers.
• Flow Sheet C Required 1 Shift Supervisor, 2
Chief Operators, 1 Operator and 1 Laborer.
• Flow Sheet E Required 2 Shift Supervisor, 2
Chief Operators, 3 Operators and 3 Laborers.
.
Opportunities to Reduce Cost of “Next
Generation” Third Wave Plants
• Each of the Previous Plants had its
Strong Points and Weak Points.
• Combining the Best of Each can Reduce
Both Capital and Operating Costs
.
Opportunities to Reduce Cost of “Next
Generation” Third Wave Plants
• For Example
.
– Solvent Losses Varied by Over a factor of Three ($4->$12/Kg
U3O8)
(Flow Sheet C the Lowest, Flow Sheet A the Highest)
– Pretreatment Costs Varied by More than a Factor of Three.
($0.50->$9.00/Kg U3O8)
(Flow Sheet A the Lowest, Flow Sheet B the Highest)
– The Total of Solvent Loss Cost and Pretreatment Cost Varied by
Over a Factor of Three ($5.70->$17.00/Kg U3O8)
– Flow Sheets A and C Required 5 First Cycle Stages of Extraction
Whereas Flow Sheet B Only Required 4
– Flow Sheet A Required 5 First Cycle Stages of Strip, Whereas Flow
Sheets C and B Only Required 3.
– Both Flow Sheets A and C Experienced “Reduced Extraction
Coefficients” (Solvent Poisoning), Flow Sheet B did not
Opportunities to Reduce Cost of “Next
Generation” Third Wave Plants
• For Example
.
– Average Solvent Concentrations in the Raffinate Ranged
From 5 ppm to 100 ppm
(Flow Sheet C the Lowest, Flow Sheet A the Highest)
– P2O5 Losses Ranged from <0.1% to ~1%
– Acid Dilution Ranged from Nil to >1%
– Strip Coefficients Ranged from 15 to 150
(Flow Sheet B the Lowest, Flow Sheet C the Highest)
– Solvent Loss Due to Settler Cleanings Ranged from <.1 to
>.5 Kg/tonne P2O5 Processed
– Some Equipment Remains From the Original Plants and is
Still Operating
– Some Plants had Negative Impact on Fertilizer Production,
Some Had Positive Impact
Opportunities to Reduce Cost of “Next
Generation” Third Wave Plants
• For Example
.
– Oxidation Cost Ranged from $0.10 to $1.65/Tonne
P2O5
(Flow Sheet A the Lowest, Flow Sheet C the
Highest)
– Fe+2/Fe Added ranged from < 2 to >3
(Flow Sheet B the Lowest, Flow Sheet D the
Highest)
– Second Cycle Operating Costs Were Similar, but
One had a Significantly Lower Capital Cost
(Flow Sheet B the Lowest)
.
Opportunities to Reduce Cost of “Next
Generation” Third Wave Plants
• During the Operation of the Plants, Studies were
Conducted to Understand the Reasons for these
Differences
• Most are Well Understood
• Most Significantly, the Causes of Crud Were
Determined
• Taking Advantage of this Understanding can
Significantly Reduce Both the Capital and Operating
Costs of the “Next Generation” Plants
• Reductions as Much as 40% in Both Capital and
Operating Costs Are Likely
.
Estimates of Current Operating Costs
Third Wave
• Current Operating Costs Will be Higher Due
to:
– Lower Uranium Content of Rock (for Central
Florida Plants)
(0.50 Kg/Tonne Previously to Estimated 0.40-0.45
Kg/Tonne for Next 10 Years)
– Somewhat Higher Solvent Cost
– Higher Electricity Cost
– Higher Labor Cost (Can be Offset with Automatic
Controls)
– Total Cash Operating Costs Should be Less than
$40/Kg
– + Regulations ??? $
.
Estimates of Current Capital Costs
• Capital Costs (Adjusted for Inflation) Should
Be Lower than Previous Plants, but Highly
Dependent on Flow Sheet Adopted
.
• What if we do the Best of the Best and
Avoid the Worst and the Failures.
• Say a facility of 1,000,000 # U3O8/Yr,
450,000 Kg/yr.
• FEED Study……………….
• Capital $100MM to $150MM
• Operating Cost < $20/#, < $44/Kg
• Looks Good, Eh!!!!!!!
Risks
• Most Fertilizer Producers are Concerned with
the Effect the Uranium Recovery Plant Will
Have on Their Operations
–
–
–
–
–
P2O5 Losses
Effect on Rubber Lined Equipment
Acid Dilution
Acid Reheat
Product Grade of Fertilizer Products
• All These were Found to be Minimal or
Positive in the Better Designed and Operated
Plants
.
Risks
• Not Much Detail Has been Published On the Plants
from the Previous Generation
• Many Documents Have Been Destroyed for Legal
Reasons or from Neglect
• Most of the “Know How” is in the Memories and
Personal Archives of a Diminishing Number of Key
People
• Average Age of the Most Knowledgeable People is in
the 70s
• We Are Probably Losing “Know How” and Operational
Expertise at the Rate of 10%/yr
• Relearning this Information Would Cost Several 10’s
of Millions of Dollars
.
Risks
• The Most Effective Way to Capture this
Valuable Knowledge is to Build a “ReDemonstration Plant” as Quickly as Possible.
• Training Programs For Those Interested.
• The Second Most Effective Way to Capture
this Valuable Knowledge is to Conduct in
Depth Interviews with the Key People
• As We Speak, the Phosphate Industry is
“Throwing Away” Enough Uranium every Four
Days to Fuel a Nuclear Power Plant for a
Year!
.
What About Hemi or 40% Clarifies Acid?
• Octyl Phenol Phosphoric Acid Solvent has
Been Demonstrated to Work Effectively in Lab
• Operating and Capital Costs will be about the
Same per Pound as Central Florida
• Piloting Will be Required fro any New Solvent
or Acid Strength.
.
Other Opportunities
• New Solvents
– Octyl-Phenol-Phosphoric Acid
• Lower Cost
• Higher Extraction Coefficient
• Many Others have been reported
• New Contactors
– Columns
• New Technology
–
–
–
–
–
Ion Exchange
Ultrafiltration
Micro-emulsions
Chelating Agents
Computer Controls
.
Uranium from Phosphates
• So How Much Uranium Can We
Recover?
•0 Kg
• If We Procrastinate
• Been There
• Done That
• Thank You