17 Fertilizer Nuclear-Fuel Connection

8/8/2019 17 Fertilizer Nuclear-Fuel Connection

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Connections between PhosphateConnections between PhosphateFertilizerFertilizerProduction and theProduction and the

Uranium Fuel CycleUranium Fuel Cycle

Richard A. Brand

Department of Physics

& Responsible for radiation safety

University of Duisburg-Essen

(Multifos: Tricalcium Phosphate)


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Plan Naturally occurring radioactive materials (NORM) Technologically enhanced natural radioactivity:

Phosphate Fertilizers & distribution of contaminants

NORM or Technologically enhanced radioactivity?

Health effects from use of phosphate fertilizers?

Example of Uranium and Radium Removal

Waste Products of Phosphate Fertilizers: phosphogypsum

Interest in recovering uranium

Rekindled Interest in recovering uranium and cleaningphosphogypsum

What should be done


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Naturally occurring radioactive materials (NORM)

Biggest problem high-LET exposure: Radon

Ref: BEIR VII Health Risks from Exposure to Low Levels ofIonizing Radiation, National Research Council 2006


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Ref: BEIR VII Health Risks from Exposure to Low Levels ofIonizing Radiation, National Research Council 2006

Typical risk calculation based on low-LET exposure!

Radiation protection:

Linear no-threshold model generally accepted.Dilution among the general public does not help matters.

Generally little governmental controlfor materials with less than1000 Bq/kg.

Approximant limits for no control:U238+ (Th,Pa) 500Bq/kgU238sec (Th, Po) 10 Bq/kgRa226++ (Rn, Po) 10 Bq/kg

Ref: Strahlenschutzverordnung 2001


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Bundesamt fr Strahlenschutz, Berlin

Natural environmental radioactivity


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Technologically enhanced natural radioactivity:Production of Phosphate Fertilizers

Ref: W. E. Falck & D. Wymer, I.A.E.A. Vienna

Sulfuric acid process:


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Natural uranium (no daughter isotopes): 25 Bq/mg

All radioisotopes land up somewhere!Radium in the gypsum!

Sulfuric acid process:



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Natural uranium (no daughter isotopes): 25 Bq/mg

All radioisotopes land up in the fertilizer!

Nitric acid process:



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OrTechnologically enhancednatural environmental radioactivity?

If much of the uranium in farmed

soil is of anthropogenic origin,

why is it listed under Naturalenvironmental radioactivity?


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Verwendung von PhosphatdngemittelnDie in Deutschland eingefhrten Rohphosphate, dievorwiegend aus den USA, Nordafrika und Israel kommen,weisen gegenber .der Bden einen bis zu fnfzigfacherhhten Gehalt an U-238 und Ra-226 auf.

Die spezifischen Aktivitten der daraus hergestelltenmineralischen Phosphatdnger betragen fr :

U-238 280 - 920 Bq/kg (TSP max. 3000 Bq/kg),

Radium-226 160 - 520 Bq/kg (TSP max. 1150 Bq/kg )K-40 30 - 6200 Bq/kg

Messungen ergaben fr Lagerarbeiter 2,3 mSv pro Jahrund in der Landwirtschaft maximal 1 mSv pro Jahr.

Technologically enhanced natural environmental radioactivity


Situation in Germany:


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RICHTLINIE 96/29/EURATOM DES RATES vom 13. Mai 1996

Artikel 13Dosisgrenzwerte fr Einzelpersonen der Bevlkerung

(1) Unbeschadet des Artikels 14 sind die in den Abstzen 2 und 3 festgelegtenDosisgrenzwerte fr Einzelpersonen der Bevlkerung einzuhalten.

(2) Der Grenzwert der effektiven Dosis betrgt 1 mSv pro Jahr. Allerdings kannunter besonderen Umstnden ein hherer Wert der effektiven Dosis pro Jahrzugelassen werden, sofern der Mittelwert ber fnf aufeinanderfolgende Jahre1 mSv pro Jahr nicht berschreitet.

Question: do farmers carry film dosimeters?


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Health effects from use of phosphate fertilizers?

One example: Tobacco

Apatite: Ca5(PO4)3(OH,F,Cl)Source: National Institute of Health

http://en.wikipedia.org/wiki/Health_effects_of_tobacco_smoking

tobacco grown in India averaged only 0.09 pCi per gramof polonium 210, whereas tobacco grown in the UnitedStates averaged 0.516 pCi per gram.

One factor in the difference between India and the UnitedStates may be the extensive use of apatite as fertilizer fortobacco in the United States;

The amount of polonium 210 inhaled from a pack of 20cigarettes is therefore about 0.72 pCi. independent ofany form of filtering or 'low tar' cigarette.

Compared to nonsmokers, heavy smokers have four timesgreater radioisotope density throughout their lungs.

the alpha particle dosage from polonium 210 received

by smokers of two packs a day was .. 150 times higherthan .. from natural background radiation.


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Options for the extraction of U from phosphoric acid

1. Precipitation of U from phosphoric acid,using an organic reagent (e.g. acetone) as dispersant, and ammonium fluoride (NH4F) asprecipitant. Reduction of U6+ to U4+ by addition of Fe powder. Recovery of U (for the production

of yellow cake) from the precipitate by dissolution in diluted H2SO4 or HNO3 and subsequentpurification by ion exchange or solvent extraction.

2. Ion exchange separation with a chelating resin(with subsequent elution and precipitation to produce yellow cake)

3. Membrane separation of U, using liquid membranes with a strong affinity for U (as yet stillin experimental development stage)

4. Froth flotation

complexing U with a surface active agent of hydrophobic nature (froth needs to be purified toproduce high grade yellow cake)

5. Solvent extraction (capable to be practiced on a large commercial scale)using various synergistic mixtures of organic solvents such as DNPPA (di nonyl phenylphosphoric acid)+TOPO (tri n octyl phosphine oxide), followed by purification and precipitation=> U extraction rates of >90% can be realized

after Singh et al. (2001), Gupta & Singh (2003)Thanks to Sylvia Kratz et al.

Examples of Uranium and Radium Removal


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Examples of Uranium and Radium Removal

Environmental Considerations On Uranium AndRadium From Phosphate Fertilizers

T.M. CIOROIANU, F. BUNU, D. FILIP, Gh. FILIP

in

Impact of new environmental and safety regulationson uranium exploration, mining, milling andmanagement of its wasteProceedings of a Technical Committee Meeting, 1998,

IAEA

Nitric acid attack:

1) No gypsum formed.2) all radioisotopes in liquid3) Radium removed by copercipitationwith BaSO44) Uranium and rare earths removed

using solvent extraction


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For 1 Kilo fertilizer, 5 kilos phosphogypsum (calcium sulfate)

Florida: 32 million tones per year

Most of phosphogypsum lands on stacks

Much is dumped (oceans) or used in agriculture!

Efforts to create secondary markets hampered bycontamination with radium.

Possible uses (when not contaminated):

Construction Agriculture Landfill

Waste Products of Phosphate Fertilizers:

phosphogypsum.


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Stacks need to be sealed:

similar to uranium mine tailings.Source of radon.Can contaminate aquifer system.Sinkholes

Phosphogypsum Stacks


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Disposal into the oceans:

Example:LebaneseChemical

Company

GreenpeaceResearch

Laboratories2002


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Commercial interest inrecovering uranium depends on

market price

Thanks to Ewald Schnug


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Interest in recovering uranium and incleaning up phosphate:

past

Uranium has been recovered from fertilizer production in several countries:

USA, IMC Global (now Mosaic) up to 1999Belgium up to 1996Kazakhstan, Ulbinski & ShevchenkoPakistan, MultanIraq: Al-QuaimIsrael

Commercial recovery ceased due to price of uranium.


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Industrial Facilities for Uranium RecoveryInformation fromhttp://www.wise-uranium.org/pfac.html

Outdated!!


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Possible recoverable uranium:

Advantage of U extraction:

Potential U resources in phosphate rock are estimated to range between 15

and 22 Mio t U (WISE, 2000; UIC, 2005). At the current global rate ofconsumption (68000 t U/year; UIC, 2005), phosphatic uranium could meet the

global demand for about 220 to 324 years. As a side effect, U input into

agricultural soils with mineral P fertilization would be reduced.

Known conventional U resources, on the other hand, are around 3.5 Mio t U,and will only last for about 50 years (UIC, 2005).

=> Sustainable resource management

Disadvantage: Higher market price for P containing mineral fertilizers

Thanks to Sylvia Kratz et al.


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Interest in recovering uranium formilitary and clandestine purposes:

Iraq

al Qaim phosphate plantand uranium extractionfacility (Unit-340).

The unit was designed toproduce 54 tonnes ofuranium peroxide peryear.

http://www.isis-online.org/publications/iraq/alqaim.html


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Interest in recovering uranium for

military and clandestine purposes:Israel

Israel has also devised amethod of extracting uraniumfrom the phosphate deposits inthe Negev desert, where there

is an estimated 30000 to60000 tons of uranium inphosphate ores.

Active mining of phosphate

deposits takes place in theNegev near Beersheba.

Immediately adjacent toDimona reactor.

Negev: Contamination of water resourcesin Southern Israel

http://www.iued.org.il


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0.0068 0.0069 0.0070 0.0071 0.0072R(

235U/

238U)- isotope ratio

0

10

20

30

40

50

Mean = 0.0072Std. Dev. =

5.0168E-5N = 65

Histogram ofR(235U/238U)-isotope ratioin different types of samples

Typical R(235

U/238

U) = 0 .007202

5.1E-5 5.2E-5 5.3E-5 5.4E-5 5.5E-5 5.6E-5 5.7E-5 5.8E-5R(

234U/

238U)- isotope ratio

0

5

10

15

20

25

Mean = 5.521E-5Std. Dev. = 1.2606E

N = 67

Histogram ofR(234U/238U)- isotope ratio indifferent types of samples

Secular equilibrium

Fig. 10: Frequency histogram (frequency distribution) ofR(235U/238U) in fertilisers samples of different type

Fig. 11: Frequency histogram ofR(234U/238U) in67 fertilisers samples of different type

Sattouf et al., (2006) U and Sr isotope ratios in rock phosphates& talk at this symposium

Sample with possibledepleted uranium

Could be an Interest in recovering uranium formilitary and clandestine purposes:

Possible to hide U enrichment in fertilizer production:


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Rekindled Interest in recovering uranium:

Started with $1M AEC-funding of IMC plant in Florida(Time Magazine Apr. 12, 1954)

Phosphate industry may restart uranium mining as price soars(Tampa Tribune, May 11, 2007, Tampa Florida)

Florida fertilizer production:1) CF Industries2) Mosaic Corp. (IMC Global + Cargill Cop.)3) Potash Corp.

Other industrial units considering uranium recovery:

1) Yarimca Phosphoric Acid Plant, TurkeySolvent extraction, nal and AtakRadiation Safety Problems, NATO Science Series

2) Nuclear Materials Corp. Egypt

L.A. Guirguis, Can. J. Chem. 61 (1983)

3) Phosphate Research Center, MoroccoTowards a desalination initiative uranium recoveredfrom Moroccan phosphoric acid productionLung et al., Int. J. Nuclear Desalination 2005


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Rekindled Interest in cleaning phosphogypsum:

Dr. Bill Burnett surveys the crater-like summitof Florida's largest GYP stack at IMC-Agrico

Presently:

Phosphogypsum stacks

capped with plastic

Cost: 10 to 20 M$/stack

Constant monitoring

necessary

Danger to aquifer systems

Radon emissionAny use proposed must consider:

Potential of release of Ra into environment Radon emitted into atmosphere Potential re-use and loss of institutional control


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Conversion of phosphogypsum to Sulfate fertilizer using

Merseberg process:

Radionuclide flow during the conversion of phosphogypsum to ammonium sulfateW. C. Burnett et al., Journal of environmental radioactivity 1996

& The Florida Institute of Phosphate Research


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Recovering phosphogypsum for use:

Main problems:

Application of phosphogypsum, in building materialshas been limited by the presence of minor componentsthat are hazardous, such as radioactive substances, ..,.

The worldwide use of phosphogypsum in buildingmaterials is probably well below 15% of output. In theUS, use was banned in 1990 and in theEuropean Union, it was discontinued by 1992.

Recently, uranium levels in .. phosphogypsum haveincreased due to reduced uranium extraction.

use in building materials of another type of waste

gypsum, generated by flue gas desulphurization, hasrapidly increased.

L. Reijnders, Building and Environment 42 (2007) 1036.


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Recovering phosphogypsum for use:

. separation techniques may reduce the concentrations ofsuch [radioactive] components.

Higher waste disposal costs, tighter regulations and higher pricesfor competing virgin minerals could make the use of the purifiedphosphogypsum in building materials more attractive.

L. Reijnders, Building and Environment 42 (2007) 1036.


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In Line Purification of Process Slurries

.. Two methods have been investigated:(i) supported liquid membrane extraction, and(ii) ion exchange bars.

Both methods have successfully been applied to

the solvent-mediated recrystallization of calciumsulphate.

C. Koopman, G. J. Witkamp, G. M.Van Rosmalen,Removal of heavy metals andlanthanides from industrialphosphoric acid process liquors,

Separ. Sci. Technol. 1999, 34(15),2997-3008

Mechanical, MaritimeAnd Materials Engineering


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Technical means for clean up and recovery exist

What is urgently needed:

1. Monitoring and limits for total radioisotopes in fertilizers!

2. Necessity for monitoring: avoid uranium black market,utilize an important raw material!

3. Clean-up of radioisotopes in both fertilizer and byproducts.

4. Controlled commercial usage or burial of radioisotopesextracted.

What should be done


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17 Fertilizer Nuclear-Fuel Connection