Uranium Recovery from Phosphoric Acid

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 

6 th to 10 th 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. 

• What was done that did not work. 

• What did work. 

• What we would not do again. 

• What 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. 

.

P 2 O 5 

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 

– Range: 0.1-7 Kg/Tonne of P 2 O 5 

– Typically: 0.3-0.6 Kg U per Tonne P 2 O 5 

– Price: Volatile, but in 2007, U 3 O 8 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 

.

Westinghouse Plant at Farmland Industries 

Refinery Building 

UR Plant Area 1 Hectare 

First Stage Mixer Settlers 

.

Control Room 

.

IMC Plant at New Wales 

.

IMC Plant at New Wales 

UR Plant Area 2.5 Hectares 

Clarifiers and Carbon Columns 

First Stage Mixer Settlers 

.

Uranium Recovered From 

Phosphoric Acid in the USA 

1.5 

Millions 

of Kg of 

U3O8 

1 

0.5 

0 

1978 1982 1986 1990 1994 1998 

Total U 3 O 8 Recovered Approximately 20 Million Kgs .

Flow Sheets of Recent U.S.A. Plants 

Incoming 

30% Acid 

Acid Pretreatment 

First Cycle Extraction 

Raffinate 

Post Treatment 

Second Cycle 

Extraction 

Pregnant 

Solvent 

Loaded 

Strip Acid 

First Cycle Strip 

Barren 

Solvent 

Strip Acid 

Second Cycle 

Strip 

Pregnant 

Solvent 

Loaded 

Strip Solution 

Precipitation of Uranium, 

Drying, and Calcining 

Ship to 

Converter 

.


• All Plants Extracted Uranium from Acid 

Produced by Dihydrate Processes (27-28% 

P 2 O 5 Plus 1.5-3% Sulfate) 

• All Acids were Produced from Central Florida 

Rock 

• U 3 O 8 Content of All Acids was About 0.5 

Kg/Tonne P 2 O 5 

• All Used a Solvent Extraction Process 

• The Processes were Developed by 

Westinghouse, IMC (3 Plants), Uranium 

Recovery Corp., Freeport (2 Plants), and 

. 

Gardinier


• Acid Pretreatment 

. 

– Westinghouse Flash Cooled to 38 o C, 

Clarified with Flocculent and Reheated to 

40 o C 

– IMC Used Spiral Coolers to Cool 49 o C, 

Added Clay and Flocculent Before 

Clarification, then Passed Acid Through 

Carbon Columns (Abandoned after 6 

Years)


• 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 o C Using 2 

Stage Flash coolers and Clarified the Acid. 

The Acid was Reduced with Scrap Iron and 

then Filtered Using Pressure Leaf Filters 

.


• 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 Extractant Solvents 

– 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


• 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


• 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 

.


• First Cycle Stripping 

. 

– Westinghouse Used 27% P 2 O 5 Acid Reduced with 

Scrap Iron Plus Powdered Iron Within Stages 

– IMC Used 31% P 2 O 5 Acid Plus Sulfuric with Iron 

Ball Towers for Each Stage for Reduction 

– URC Used 40% P 2 O 5 Acid Plus Peroxide 

– Freeport Used a Boosted Strength 31% P 2 O 5 Acid 

With Iron Ball Towers for Each Stage for 

Reduction 

– Gardinier Stripped the Solvent Using 15% HF


• 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 


– The Gardinier Process Did not Require Oxidation 

.


• 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+% U 3 O 8 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% U 3 O 8 Recovery (Down 

– Weekly for Line Scrubs and Yearly Turn Around) 

.


• 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% U 3 O 8 Recovery (Down 

Weekly for Line Scrubs and Yearly Turn 

Around) 

• The Gardinier Plant Obtained About 90% 

Recovery 

.


• Westinghouse Plant Produced Over 137,000 Kg/Yr 

U 3 O 8 . 

• IMC New Wales Plant Produced as Much as 591,000 

Kg/Yr U 3 O 8 . CF Plant City Module Produced as Much 

as 409,000 Kg/Yr U 3 O 8 . One CF Plant Closed Down 

After Less than 3 Years of Operation 

• URC Plant Produced About 45,000 Kg/Yr U 3 O 8 . 

• Freeport Plants Produced as Much as 482,000 Kg/Yr 

U 3 O 8 . (Combined) 

.

. 

Plant / Design Freeport Gardinier IMC Uranium 

Recovery Corp. 

Pretreatment No cooling 2-stage flash Spiral coolers No cooling 

Cooling 

cooling - 32 o C cool - 49 o C 

Solids 

Removal 

Further 

Pretreatment 

Oxidation 

State Change 

First Cycle 

Solvent 

Mixer Settler 

Design 

First Cycle 

Strip Solution 

Second Cycle 

Oxidation 

State Change 

Second Cycle 

Solvent 

Uranium 

Precipitate 

Form 

Flocculant added 

before 

clarification 

Filtered using 

pressure leaf 

filters 

Clay 

/flocculant 

added before 

clarification 

None None Colour 

removal - 

activated C 

Oxidised with 

oxygen 

DEHPA/TOPO 

Low profile 

rectangular 

pumper-mixer 

settlers 

31% P 2 O 5 acid 

plus iron 

Oxidised with 

oxygen 

Reduced 

with scrap Fe 

Octyl pyrophosphoric 

acid (OPPA) 

Rectangular 

pumper-mixer 

settlers 

15% HF 

precipitated U 

as green salt 

Dissolved in 

nitric acid 

Oxidised with 

H 2 O 2 . Later O 2 

DEHPA/TOPO 

Circular mixer 

settlers 

31% P 2 O 5 acid 

plus sulphuric 

acid and iron 

Oxidised with 

H 2 O 2 . Later 

used oxygen 


before 

clarification 

None 

Reduced using 

ferro-silicon 

Octyl pyrophosphoric 

acid 

(OPPA) 

Deep-cone 

bottom settlers 

40% P 2 O 5 acid 

plus hydrogen 

peroxide 

No oxidation 

change required 

Westinghouse 

Flash cool - 38 o C 


before 

clarification 

None 

Oxidised using 

nitric acid 

DEHPA/TOPO 

Low profile 

rectangular 

pumper-mixer 

settlers 

27% P 2 O 5 acid 

plus iron 

Oxidised using 

nitric acid 

DEHPA/TOPO TBP DEHPA/TOPO DEHPA/TOPO DEHPA/TOPO 

Ammonium 

diuranate 

Ammonium 

diuranate 

Uranyl 

peroxide 

Ammonium 

uranyl 

tricarbonate 

Ammonium 

uranyl 

tricarbonate

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 

.


• Westinghouse Total Cash Cost (Including Royalty, 

Cost of Acid Dilution, Losses and Reheat) was About 

$37/Kg U 3 O 8 ($24/Kg w/o Royalty etc) 

• IMC (New Wales) Cash Operating Costs (No Royalty, 

Dilution, Reheat or Loss Cost) was About $24/Kg 

U 3 O 8 

• URC Total Cash Cost (Including Royalty, Cost of Acid 

Dilution and Acid Losses) was About $100/Kg U 3 O 8 

(Low Throughput and Operating Factor) 

• Freeport Cash Operating Costs (No Royalty, Dilution, 

Reheat or Loss Cost) was About $26/Kg U 3 O 8 

• Gardinier Cash Operating Cost was About $40/Kg 

U 3 O 8 

.


• 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 

.



• For Example 

– Solvent Losses Varied by Over a factor of Three ($4->$12/Kg 

U 3 O 8 ) 

(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 U 3 O 8 ) 

(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 U 3 O 8 ) 

– 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 

.




– Average Solvent Concentrations in the Raffinate Ranged 

From 5 ppm to 100 ppm 

(Flow Sheet C the Lowest, Flow Sheet A the Highest) 

– P 2 O 5 Losses Ranged from 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 .5 Kg/tonne P 2 O 5 Processed 

– Some Equipment Remains From the Original Plants and is 

Still Operating 

– Some Plants had Negative Impact on Fertilizer Production, 

Some Had Positive Impact 

.




. 

– Oxidation Cost Ranged from $0.10 to $1.65/Tonne 

P 2 O 5 

(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) .



• 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 “Re- 

Demonstration 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

Uranium Recovery from Phosphoric Acid

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