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Potassium FertilizerProduction and

Technology

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Potassium Cycles through Complicated Ecosystems

to Sustain Plant and Animal Life

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Potassium Is Essential

for Plants

Taken up by the plant as K+

Does not form organic compounds in the plant

Is vital to photosynthesis and protein synthesis

Is associated with many metabolic functions

Essential role for regulating leaf

stomata and controlling water use

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Potassium and Animal Nutrition

Potassium is essential for many metabolic functionsIt maintains salt balance between cells and body fluidsAdequate K is essential for nerve function and preventing muscle crampsIt is routinely added to many animal feeds

Since K+ is not stored in the human body,dietary replacement is required on a regular basis.

Government agencies state that:

diets containing foods that are good sourcesof potassium and low in sodium may reducethe risk of high blood pressure and stroke.

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The History of Potash

Element symbol K comes from Latin Kalium

Allow trees to bioaccumulate K andboil wood ash to recover nutrients

Wood ash boiled in pots (pot-ash)

Not a sustainable practice

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Potassium Fertilizer Is Mined and Produced in

Many Parts of The World

Many other deposits are located throughout the world

(size of dot proportional to production in 2009)

http://upload.wikimedia.org/wikipedia/commons/b/b4/A_large_blank_world_map_with_oceans_marked_in_blue.gif

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Some Common

Potassium-Containing

Minerals

Mineral Composition K2O content

(approx %)Chlorides:

Sylvinite KCl

NaCl 28Sylvite KCl 63Carnalite KClMgCl26H2O 17Kainite 4KCl4MgSO411H2O 18

Sulfates:Polyhalite K 2SO42MgSO42CaSO42H2O 15Langbeinite K2SO42MgSO4 22Schoenite K 2SO4MgSO44H2O 23

Nitrates:

Niter KNO3 46

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Potash Is Obtained By:

Shaft mining

Solution mining

Evaporation of brines

Most potash deposits are too deepunderground for surface mining

Water bodies such asthe Dead Sea andthe Great Salt Lake

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Potash Deposit

Example: Saskatchewan Deposits

The depth of the ore maylimit access to the deposit

The Largest Potash

Deposits Are Deep

Beneath the Earths

Surface

Potash recovery requires

complex and expensivemining techniques

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Conventional

Shaft Mining

Vertical shafts drilledto the depth ofpotash deposit

Lifts are installed toprovide access forequipment, workers,and to remove ore

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Conventional Shaft Mining

Vertical shafts drilled into the earthOre veins are extracted with machine mining or blast methods,adapted to the specific geologic formation

Continuous mining machines are found in many varietiesadapted to the specific geologic formation

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Conventional Shaft Mining

Vertical shafts drilled into the earthDeep horizontally-uniform ore veinsare mined with continuous mining machines

Drum-type continuous mining machine

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Conventional Shaft Mining

Vertical shafts drilled into the earthLess uniform ore veins can be mined with rotary borers

Drum-type mining machines

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Conventional Shaft Mining

Vertical shafts drilled into the earthSome ore veins are mined using blast methods

Adding explosive

prior to blastLarge underground chamber

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Mining Techniques:

Long panels Herringbone panels

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Vertical shafts drilled into the earthOre veins are minedBroken ore is transported to skip with a conveyor belt or shuttle car

Conventional Shaft Mining

Potash ore may be transported many kilometersfrom the mine face to the skip location

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Ore Storage

Crusher

Example of underground storage and ore hoisting

Conventional Shaft Mining

Vertical shafts drilled into the earthOre veins are mined with rotary borers or blast methodsBroken ore is transported to skip with a conveyor belt or shuttle carHoists bring ore to the surface for further processing

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Potash Deposit

Hoist System

to Transport

Ore to Surfaceto processing

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Crushing and Grinding

Reduce the particle size to

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Scrubbing and Desliming (Wet Separation)

Potash ore is

rinsed and agitatedwith a saturatedsalt solution toremove clay andimpurities

Martin MrazMartin Mraz

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Flotation Separation

Amine reagents coat KCl but not NaCl

Air bubbles cling to amine and float KCl to surfacewhile NaCl and clay sink to bottom

KCl

NaCl

`

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Flotation

Potassium-containingminerals rise to the surfaceof the flotation cells and thenskimmed off

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Heavy-Media Separation of KCl from NaCl

In a solution with a density between 1.99and 2.16 g/cm3, KCl will float and NaClwill sink allowing mineral separation

Ground magnetite mineral is addedto the brine to reach 2.08 g/cm3 density.

Magnetite is recovered withmagnets and reused

KCl

NaCl

Magnetite

Mineral Density (g/cm3)

KCl: 1.99NaCl 2.16CaSO4 2.96Langbeinite 2.82

Mineral Density (g/cm3)

KCl: 1.99NaCl 2.16CaSO4 2.96Langbeinite 2.82

Mineral Density (g/cm3)KCl 1.99NaCl 2.16K.MgSO4 2.83CaSO4 2.96

Magnetite 5.18

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Final Steps: Dewatering and Sizing

A final rinse with saturated brine water and thenthe finished product is dewatered, centrifuged, dried,and compacted to desired particle sizes

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Compacting

Compacting produces granular material

by compressing fine particles of hot

KCl in a roller press

The sheet of pressed flakes is

crushed and screenedto uniform sizes

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Crystallization

The process to make pure and totally soluble KCl

Hot-process: KCl is dissolved in boiling water to dissolveNaCl and KCl.

As the hot brine cools, salts differentially crystallize and are

removed from solution.

Cold process: KCl solubility is lower in cold temperaturesthan Na and Mg salts, allowing crystallization and separation

Soluble grade

Granular grade

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Electrostatic Separation (Dry Separation)

Tubeelectrode Tu

beelectrode

Cleaningbrushes

Cleaningbrushes

NaClKCl

Electrostatic generatorprovides static charge tosome minerals:

Non-conductive KCl isseparated from charged NaCl

Mixed ore

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InjectionWell

Surface Ponds

Evaporation

Submersible pumps lift the brine toevaporation ponds where the potashcrystallizes and settles to the bottom

Solution Mining

Used when potash deposits are very deep,have irregular deposits, or have becomeflooded

Heated salt water is injected

into the mine and circulatedto dissolve potash mineralsand salt from the walls

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Solution Mining Example

Brine broughtto surface fromdepth of 1000 m

Evaporatedin 180 ha of vinyl-lined solar ponds

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Potash Production Also Occurs

from Natural Salt Brines

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Tailing Disposal

Common potash ores, such as sylvinite, containsup to 50% NaCl, up to 15% clay

After potash is removed, separated salt and clay are

backfilled into the mine or stockpiled into a tailing management area

Copyright Dennis Harries 2008Copyright Dennis Harries 2008

Tailings solidify intorock-like mass (mostly NaCl)

Managed to minimizeoff-site movement

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Storage

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Shipping Potash Fertilizers

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2009 Global Potash Use, %

21

17

1514

14

12

7 China

All Others

U.S.A.

Brazil

India

Other Asia

WesternEurope

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Potassium Chloride

(Muriate of Potash; MOP)

KCl Grade: 60 to 63% K2O; 46%Cl

Primarily mined as sylvinite ore

containing KCl and NaCl

Milling and a floatation agentused to separate salts

Many colors and sizes available

Traces of iron oxide give some

particles a reddish tint

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Potassium Sulfate

(Sulfate of Potash; SOP)

K2SO4 Grade: 48 to 53% K2O

17 to 18% S

Rarely found in pure form in nature

Generally produced by manipulating

potash ores to remove other materials

Valued when both K and S are neededfor plant nutrition

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Potassium Magnesium Sulfate

(Langbeinite) K

2

SO42MgSO

4 Grade: 20 to 22% K2O

21 to 22% S

10 to 11% Mg

Distinct geologic material found inonly a few places in the world

Generally produced by manipulatingpotash ores to remove othermaterials

Valued when both K, S, and Mg areneeded for plant nutrition

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Potassium Nitrate

(Nitrate of Potash; NOP)

KNO3 Grade: 44% K2O

13% N

Made by reacting KCl withnitrate salts or nitric acid

Valued when both K and Nare needed for plantnutrition

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Small quantities of specialty potashfertilizers are made for unique cropor soil conditions, such as:

Potassium phosphate (KH2PO

4)

Potassium carbonate (K2CO3)

Potassium hydroxide (KOH)

Potassium thiosulfate (K2S2O3)

All are manufactured from basicpotash materials

Other Potassium Fertilizers

Potassium

thiosulfatePotassium

thiosulfate

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Environmental Concerns

with Potash

Potash fertilizer has no significant impacts on water or air quality

Adequate potash is required for plants to use other essential

nutrients. Healthy crop growth and efficient nutrient recoveryresults from balanced nutrition

Potash applications should be guided by soiland plant tissue testing where possible

Mine tailings require management to avoid off-sitemovement of salt and water

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KNO3

K2SO4

K2SO4 2MgSO4

KCl

KH2PO4

K2S2O3

K+ + Cl-

2K+ + SO42-

K+ + NO3-

K+ + H2PO4-

2K+ + S2O32-

2K+ + 2Mg2+

+ 3SO42-

Potash Fertilizers All Supply the Same

Nutrient in the Soil

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High Yielding Crops Remove

Large Amounts of K

Crop Yield/A

Nutrient

removal,

lb K2O/A

Yield,

mt/ha

Nutrient

removal,

kg K2O/ha

Cotton 3 bales 55 1.6 62

Rice 70 cwt 25 7.8 28

Alfalfa 8 tons 390 18 437

Maize 180 bu 45 11 50

Wheat 60 bu 20 4 22

Potato 500 cwt 275 56 310

Potassium is essential for many metabolicfunctions that directly impact crop yield and quality

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Potash Applications to Soil

Potash is often spread across a fieldor applied in concentrated bandsbeneath the soil surface

Many application techniques are used

Potash fertilizer has limited mobilityin most soils

It is retained by soil colloids oncation exchange sites

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Potash Application

through Irrigation Systems

Most K fertilizers are very water soluble and many are suitable for use inirrigation systems

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Foliar Application

Many studies have demonstratedbenefits from foliar application to plantsto alleviate stress

Foliar K applications are supplementalto the major supply of nutrients through the roots

Applications of K can alleviate mid-seasondeficiencies or supplement the soil supply duringperiods of peak demand by the plant

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Additional information onplant nutrient productionand management are

available from the IPNI website:

www.ipni.net

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International Plant Nutrition Institute

3500 Parkway Lane, Suite 550

Norcross, Georgia 30092

USA

www.ipni.net