10 - Fertilizers Industry

Fertilizers IndustryFertilizers Industry

Dr. Noaman Ul-Haq

Why Fertilize?Why Fertilize?

• Supply plant nutrientsSupply plant nutrients

I l t h lth• Improve plant health

• Enhance appearance

• Improve pest tolerance

Prepared by Dr. Noaman Ul-Haq 2

Basic Plant NeedsBasic Plant Needs

• Oxygen• Oxygen• Water • Light

N i• Nutrients• GrowingGrowing

medium


NutrientsNutrients

• Macronutrients (primary)

• Macronutrients (secondary)Macronutrients (secondary)

• Micronutrients (minor)


Macronutrients (primary)Macronutrients (primary)

• Nitrogen (growth, color)

• Phosphorus (root development)• Phosphorus (root development)

• Potassium (stress tolerance)


Macronutrients (secondary)Macronutrients (secondary)

• Calcium (cell wall structure)

• Magnesium (photosynthesis)• Magnesium (photosynthesis)

• Sulfur (growth, color)


Micronutrients (minor)Micronutrients (minor)

• Iron (chlorophyll)Iron (chlorophyll)• Zinc (chlorophyll)

M ( hl h ll)• Manganese (chlorophyll)• Copper (enzyme activator)pp ( y )• Boron (water balance)• Molybdenum (nitrogen utilization)• Molybdenum (nitrogen utilization)• Chlorine (photosynthesis)


Primary NutrientsPrimary Nutrients

• Nitrogen (N)K l t i t f t iti– Key element in turfgrass nutrition

– Promotes leaf and stem growthf– Essential component of chlorophyll molecule

– Involved in regulating the uptake of other key t i tnutrients



• Phosphorus (P)U d i th f ti d t f f– Used in the formation and transfer of energy within the plantInfluences early root development and growth– Influences early root development and growth

– Encourages plant establishment



• Potassium (K)– Used by plant in large quantities second onlyUsed by plant in large quantities, second only

to nitrogen– Key component in the formation of y p

carbohydrates– Encourages rooting and wear tolerance– Enhances drought and cold tolerance– Key component in cell wall development


Secondary NutrientsSecondary Nutrients

• Calcium (Ca)St l i fl il H– Strongly influences proper soil pH

– Essential to strong cell wall structure and cell divisiondivision

– Can improve soil structure, water retention and infiltrationand infiltration



• Magnesium (Mg)Pl i t t l i h t th i d– Plays an important role in photosynthesis and chlorophyll productionA necessary component in many essential– A necessary component in many essential enzyme systems within the plantImportant in aiding the translocation of– Important in aiding the translocation of phosphorus



• Sulfur (S)W k ith it t d t i– Works with nitrogen to produce new protein for plant growthPlays an important role in the utilization of– Plays an important role in the utilization of oxygen by the plantInfluences the level of activity of soil– Influences the level of activity of soil microorganisms


MicronutrientsMicronutrients• Iron (Fe)Iron (Fe)

– Necessary for the formation of chlorophyll– Deficiencies are most common in wet, cold or high pH g p

soils– Aids in the activation of a number of biochemical

processes within the plantprocesses within the plant• Manganese (Mn)

Important in the formation of chlorophyll and the– Important in the formation of chlorophyll and the activation of initial growth process

– Generally available in sufficient quantities in the soil


MicronutrientsMicronutrients• Boron (B)Boron (B)

– Necessary for plant reproduction– Helps maintain optimum water balance inHelps maintain optimum water balance in

plants

• Molybdenum (Mo)– Essential to the process of nitrogen utilizationp g– Is less available under acidic (low pH) soil

conditions


MicronutrientsMicronutrients• Zinc (Zn)( )

– Necessary for the production of chlorophyll

• Copper (Cu)– Important in the synthesis of certain plant growth

substancessubstances– Serves as an activator for several essential enzymes– Needed only in small quantities; large amounts can y q g

be toxic to turfgrass plants– Deficiencies are usually only found in highly alkaline

soils (high pH) organic soils or heavily leeched soils


soils (high pH) organic soils or heavily leeched soils

What is Fertilizer?What is Fertilizer?

• Supplies basic plant nutrients

−N – Nitrogen

−P – Phosphorus

−K – Potassium


Fertilizer Analysis(N-P-K)

• Percentage by weight of g y gnutrients

Elemental nitrogen (N)–Elemental nitrogen (N)–Available phosphorus (P2O5)p p ( 2 5)–Soluble potash (K2O)


Element Key Raw Materials

Key Products

Nit (N) H d b U iNitrogen (N) Hydrocarbons, principally Natural

Gas

Urea, ammonium nitrate, CAN, UAN,

ammonium sulphate

Phosphorus (P)

Phosphate Rock DAP, MAP, TSP, SSP(P) (+ Ammonia) SSP

Potassium (K)

Potash (potassium chloride or KCl)

Potash, potassium(K) chloride or KCl) potassium sulphate,

potassium nitrate


Nitrogenous Fertilizer ProductsNitrogenous Fertilizer Products• Ammonia liquor • Ammonium nitrate • Ammonium sulfate • Anhydrous ammoniaAnhydrous ammonia • Aqua ammonia • Fertilizers, mixed, produced in nitrogenous fertilizer

plantsplants • Fertilizers, natural • Nitric acid

Nit f tili l ti• Nitrogen fertilizer solutions • Plant foods, mixed in nitrogenous fertilizer plants • Urea


Nitrogen Fertilizer ProductionNitrogen Fertilizer Production• Nitrogenous Fertilizers production is based on Ammonia, g p

produced from some kind of hydrocarbon as feedstock• Ammonia Production :

– Ammonia is produced mainly through processing ofAmmonia is produced mainly through processing of hydrocarbons by Steam Reforming.

– This is an endothermic process and requires huge energy for processing.p g

– The hydrogen from natural gas is reacted with nitrogen from the air to produce anhydrous ammonia.

– Hydrogen is obtained from either the catalytic steam reforming of natural gas (methane) or naptha, or as the byproduct from the electrolysis of brine at chlorine plants.

– Ammonia is used directly as a fertilizer or used to produce other forms of fertilizers


forms of fertilizers.

Products

Nitric

Ammonia

O2

Acid LiquidAm Nitrate

UAN UAN

AmNitrate

Urea

UANBlending

UANSolutionsAnhydrous

AmmoniaNatural

Gas

AirCO2

Granulation

AmmoniatedPh h t

Urea

AmmoniatedPh h t

Air

Phosphates

Phos Acid

Phosphates


Ammonia ProductionAmmonia Production• Following steps are required to produceFollowing steps are required to produce

synthetic ammonia using the catalytic steam reforming method:

1. natural gas desulfurization 2. catalytic steam reforming 3. carbon monoxide shift 4. carbon dioxide removal 5 methanation5. methanation 6. ammonia synthesis7 storage and transport


7. storage and transport


1 natural gas desulfurization1. natural gas desulfurization

• In the natural gas desulfurization step theIn the natural gas desulfurization step, the sulfur content (primarily as H2S) in natural gas feedstock is reduced to below 280gas feedstock is reduced to below 280 micrograms per cubic meter to prevent poisoning of the catalyst used in thepoisoning of the catalyst used in the catalytic steam reforming step.


• Sulfur removal requires catalytic h d ti t t lfhydrogenation to convert sulfur compounds in the natural gas to gaseous h d lfidhydrogen sulfide:H2 + RSH → RH + H2S(gas)

• The gaseous hydrogen sulfide is then absorbed and removed by passing it y p gthrough beds of zinc oxide where it is converted to solid zinc sulfide:H2S + ZnO → ZnS + H2O


2 catalytic steam reforming2. catalytic steam reforming

• Next, the desulfurized natural gas is preheatedNext, the desulfurized natural gas is preheated by mixing with superheated steam. The mixture of steam and gas enters the primary reformer tubes which are filled with a nickel-based reforming catalyst, and the tubes are heated by

t l il fi d b A i t lnatural gas or oil-fired burners. Approximately 70 percent of the methane(CH4) is converted to hydrogen (H ) and carbon dioxide (CO )hydrogen (H2) and carbon dioxide (CO2), according to the following reaction:0.88CH4 + 1.26air + 1.24 H2O → 0.88CO2 +N2 + 3H2


4 2 2 2 2

• The remainder of the CH4 is converted to H2 and CO This process gas is then sent to theCO. This process gas is then sent to the secondary reformer, where it is mixed with compressed hot air at 540°C (1004°F). p ( )

• Sufficient air is added to produce a final synthesis gas having a hydrogen-to-nitrogen mole ratio of three to one.

• The gas leaving the secondary reformer (primarily hydrogen, nitrogen, CO, CO2, and H2O) is then cooled to 360°C (680°F) in a waste heat boiler before being sent to the carbonheat boiler before being sent to the carbon monoxide shift.


3 carbon monoxide shift3. carbon monoxide shift

• After cooling, the secondary reformer effluentAfter cooling, the secondary reformer effluent gas enters a high temperature (350-400°C) CO shift converter which converts the CO to CO2, followed by a low temperature (200-250°C) shift converter which continues to convert CO to CO2. Th hi h t t CO hift t i fill dThe high temperature CO shift converter is filled with chromium oxide initiator and iron oxide catalyst The following reaction takes place:catalyst. The following reaction takes place:CO + H2O → CO2 + H2


• The exit gas is then cooled in a heat exchanger before being sent to a low temperature shift g pconverter for ammonia, amines, and methanol where CO continues to be converted to CO2 by a copper oxide/zinc oxide catalyst.a copper oxide/zinc oxide catalyst.

• In some plants, the gas is first passed through a bed of zinc oxide to remove any residual sulfur contaminants that would poison the lowcontaminants that would poison the low temperature shift catalyst.

• In other plants, excess low temperature shift p pcatalyst is added to ensure that the unit will operate as expected. Final shift gas from this converter is cooled from 210 to 110°C (410 to (230°F) and unreacted steam is condensed and separated from the gas in a knockout drum.


• The final shift gas then enters the bottom of the carbon dioxide absorption system Thecarbon dioxide absorption system. The condensed steam (process condensate) contains ammonium carbonate ([(NH4)2CO3 • H O]) f th hi h t t hift tH2O]) from the high temperature shift converter, methanol (CH3OH) from the low temperature shift converter, and small amounts of sodium,shift converter, and small amounts of sodium, iron, copper, zinc, aluminum and calcium. Process condensate is sent to the stripper to

l til h iremove volatile gases such as ammonia, methanol, and carbon dioxide.

• Trace metals remaining in the processTrace metals remaining in the process condensate are typically removed in an ion exchange unit


4 carbon dioxide removal4. carbon dioxide removal• In this step, CO2 in the final shift gas is removed. p 2 g

CO2 removal can be done by using one of two methods: – monoethanolamine (C2H4NH2OH) scrubbing ormonoethanolamine (C2H4NH2OH) scrubbing or – hot potassium scrubbing.

• Approximately 80 percent of the ammonia plants use monoethanolamine (MEA) for removinguse monoethanolamine (MEA) for removing CO2. In this process, the CO2 gas is passed upward through an adsorption tower

t t t 15 t t 30 tcountercurrent to a 15 percent to 30 percent solution of MEA in water fortified with corrosion inhibitors.


• After absorbing the CO2, the amine-CO2 solution is preheated and regenerated in a reactivatingis preheated and regenerated in a reactivating tower. The reacting tower removes CO2 by steam stripping and then by heating. The CO2steam stripping and then by heating. The CO2gas (98.5 percent CO2) is either vented to the atmosphere or used for chemical feedstock in other parts of the plant complex.

• The regenerated MEA is pumped back to the absorber tower after being cooled in a heat exchanger and solution cooler.


5 methanation5. methanation

• Carbon dioxide absorption is not 100 percentCarbon dioxide absorption is not 100 percent effective in removing CO2 from the gas stream, and CO2 can poison the synthesis converter.

• Therefore, residual CO2 in the synthesis gas must be removed by catalytic methanation.


• In a reactor containing a nickel catalyst and at temperatures of 400 to 600°C (752 to 1112°F)temperatures of 400 to 600 C (752 to 1112 F) and pressures up to 3,000 kPa (435 psia) methanation follows the following reaction steps:CO2 + H2 → CO + H2OCO + 3H2 → CH4 + H2OCH4 + 2H2O → 6CO2 + 4H2

• Exit gas from the methanator is almost a pure three to one mole ratio of hydrogen to nitrogenthree to one mole ratio of hydrogen to nitrogen


6 ammonia synthesis6. ammonia synthesis.• In the synthesis step, the hydrogen and nitrogen y p y g g

synthesis gas from themethanator is converted to ammonia. N +3H → 2NHN2 +3H2 → 2NH3

• First, the gas is compressed to pressures ranging from 13,800 to 34,500 kPa (2000 to 5000 i ) i d ith l d th i5000 psia), mixed with recycled synthesis gas, and cooled to 0°C (32°F). This results in a portion of the gas being converted to ammonia

hi h i d d d d f hwhich is condensed and separated from the unconverted synthesis gas in a liquid-vapor separator and sent to a let-down separator.


p p

• The unconverted synthesis gas is further compressed and heated to 180°C (356°F) p ( )before entering a synthesis converter containing an iron oxide catalyst.

• Ammonia gas exiting the synthesis converter is• Ammonia gas exiting the synthesis converter is condensed and separated, then sent to the let-down separator. A small portion of the over head gas is purged to prevent the build up of inertgas is purged to prevent the build up of inert gases such as argon in the circulating gas system.

• Ammonia in the let-down separator is flashed to atmospheric pressure (100 kPa (14.5 psia)) at -33°C (-27°F) to remove impurities from the ( ) pmake-up gas. The flash vapor is condensed in a let-down chiller where anhydrous ammonia is drawn off and stored at low temperature.


drawn off and stored at low temperature.

7 storage and transport7. storage and transport

• Ammonia is typically stored at ambient pressureAmmonia is typically stored at ambient pressure and -33°C (-28°F) in large 20,000 ton tanks. Some tanks are built with a double wall to minimize leakage and insulate. If heat leaks into the tank and ammonia is vaporized, the vapors

t i ll t d d d d t dare typically captured, condensed, and returned to the tank. Ammonia is mostly transported by barge to key agricultural areas but there is alsobarge to key agricultural areas, but there is also a small system of interstate ammonia pipelines.


Urea ProductionUrea Production• The manufacture steps for urea (CO(NH2)2)The manufacture steps for urea (CO(NH2)2)

involve following unit operations: 1. solution formation 2. solids concentration 3. solids formation 4. solids cooling 5. solids screening 6 lid ti6. solids coating 7. product bagging and/or bulk shipping.



1 solution formation1. solution formation• In the urea solution synthesis operation, y p ,

ammonia (NH3) and carbon dioxide(CO2) are reacted to form ammonium carbamate (NH CO NH ) as follows:(NH2CO2NH4) as follows:2NH3 + CO2 → NH2CO2NH4

• Typical operating conditions include• Typical operating conditions include temperatures from180 to 200°C (356 to 392°F), pressures from14,000 to 25,000 kPa (140 to 250 psia), molar ratios of NH3 to CO2 from 3:1 to 4:1, and a retention time of twenty to thirty minutes


minutes.

• The ammonium carbamate is then dehydrated to yield 70 to 77 percent aqueous urea solutionyield 70 to 77 percent aqueous urea solution. This reaction follows: NH2CO2NH4 → NH2CONH2 + H2ONH2CO2NH4 → NH2CONH2 H2O

• Urea solution can be used as an ingredient of nitrogen solution fertilizers, or it can be g ,concentrated further to produce solid urea.


2 solids concentration2. solids concentration• The three methods of concentrating the urea g

solution are – vacuum concentration, – crystallization andcrystallization, and – atmospheric evaporation.

• The method chosen depends upon the level of bi t (NH CONHCONH ) i it ll bl ibiuret (NH2CONHCONH2) impurity allowable in the end product.

• Aqueous urea solution begins to decompose at q g p60°C (140°F) to biuret and ammonia. The most common method of solution concentration is evaporation.


evaporation.

3 solids formation3. solids formation • The concentration process furnishes urea "melt" p

for solids formation. Urea solids are produced from the urea melt by two basic methods:

illi d– prilling and – granulation.

• Prilling is a process by which solid particles arePrilling is a process by which solid particles are produced from molten urea. Molten urea is sprayed from the top of a prill tower. As the d l t f ll th h t t i fldroplets fall through a countercurrent air flow, they cool and solidify into nearly spherical particles


particles.

• There are two types of prill towers, fluidized bed and nonfluidized bed. The major difference is that a separate j psolids cooling operation may be required to produce agricultural grade prills in a nonfluidized bed prill tower.

• Granulation is used more frequently than prilling inGranulation is used more frequently than prilling in producing solid urea for fertilizer. Granular urea is generally stronger than prilled urea, both in crushing strength and abrasion resistancestrength and abrasion resistance.

• There are two granulation methods, drum granulationand pan granulation. I d l ti lid b ilt i l d• In drum granulation, solids are built up in layers on seed granules placed in a rotating drum granulator/cooler approximately 4.3 meters (14 feet) in diameter.

• Pan granulators also form the product in a layering process, but different equipment is used.


4 solids cooling4. solids cooling • The temperature of the nitrogenous product p g p

exiting the solids formation process is approximately 66 to 124°C (150 to 255°F). To prevent deterioration and agglomeration, the p gg ,product must be cooled before storage and shipping.

• Typically rotary drums or fluidized beds are• Typically, rotary drums or fluidized beds are used to cool granules and prills leaving the solids formation process. B l d i ill h hi h i• Because low density prills have a high moisture content, they require drying in rotary drums or fluidized beds before cooling.


g

5 solids screening5. solids screening • Since the solids are produced in a wide variety p y

of sizes, they must be screened for consistently sized prills or granules. Af li ff i ill di l d d• After cooling, off size prills are dissolved and recycled back to the solution concentration process Granules are screened before coolingprocess. Granules are screened before cooling.

• Undersize particles are returned directly to the granulator and oversize granules may be either crushed and returned to the granulator or sent to the solution concentration process.


6 solids coating6. solids coating • Clay coatings are used in the urea industry to y g y

reduce product caking and urea dust formation.• The coating also reduces the nitrogen content of

the product The use of clay coating hasthe product. The use of clay coating has diminished considerably, being replaced by injection of formaldehyde additives into the liquid or molten urea before solids formationor molten urea before solids formation.

• Formaldehyde reacts with urea to methylenediurea, which is the conditioning

Addi i d lid ki d iagent. Additives reduce solids caking during storage and urea dust formation during transport and handling.


g

7. product bagging and/or bulk hi ishipping.

• The majority of solid urea product is bulk shipped in trucks enclosed railroad carsshipped in trucks, enclosed railroad cars, or barges, but approximately 10 percent is baggedbagged.


Phosphatic Fertilizer ProductsPhosphatic Fertilizer Products• Ammonium phosphates p p• Calcium meta-phosphates • Defluorinated phosphates

Di i h h• Diammonium phosphates • Fertilizers, mixed, produced in phosphatic

fertilizer plantsfertilizer plants • Phosphoric acid • Plant foods, mixed in phosphatic fertilizer plants • Superphosphates, ammoniated and not

ammoniated


Phosphatic FertilizersPhosphatic Fertilizers• The primary products of the phosphatic fertilizers

i d t h h i id i h h tindustry are phosphoric acid, ammonium phosphate, normal superphosphate, and triple superphosphate. – Phosphoric acid is sold as is or is used as an intermediate in

producing other phosphatic fertilizersproducing other phosphatic fertilizers. – Monoammonium phosphate (MAP) is favored for its high

phosphorous content, – Diammonium phosphate (DAP) is favored for its high nitrogenDiammonium phosphate (DAP) is favored for its high nitrogen

content.– Normal superphosphate [(single superphosphate) (SSP)] has

a relatively low concentration of phosphorous, however it is used in mixtures because of its low costused in mixtures because of its low cost.

– Triple superphosphate (TSP) provides a high concentration of phosphorous, more than 40% phosphorous pentoxide.


Normal Superphosphate P d iProduction

• Normal superphosphates are prepared by reacting ground phosphate rock with 65 to 75

lf i idpercent sulfuric acid. • An important factor in the production of normal

superphosphates is the amount of iron andsuperphosphates is the amount of iron and aluminium in the phosphate rock. Aluminium (as Al2O3) and iron (as Fe2O3) above five percent 2 3 2 3imparts an extreme stickiness to the superphosphate and makes it difficult to handle.



• The two general types of sulfuric acid used in superphosphate manufacture are virgin andsuperphosphate manufacture are virgin and spent acid.

• Virgin acid is produced from elemental sulfur, g ppyrites, as well as industrial gases and is relatively pure. S t id i l d t d t f• Spent acid is a recycled waste product from various industries, such as copper, zinc, and nickel smelters, which use large quantities of , g qsulfuric acid. Problems encountered with using spent acid include color, unfamiliar odor, and toxicitytoxicity.


• Ground phosphate rock and acid are mixed in a reaction vessel held in an enclosed area forreaction vessel, held in an enclosed area for about 30 minutes until the reaction is partially completed. The reaction isCa10(PO4)6F2CaCO3 + 11H2SO4 →

6H3PO4 + 11CaSO4*nH2O + 2HF + CO2 + H2O • Then transferred using an enclosed conveyor• Then transferred, using an enclosed conveyor

known as the den, to a storage pile for curing (the completion of the reaction). ( )

• Following curing, the product is most often used as a high-phosphate additive in the production of granular fertilizers It can also be granulated forgranular fertilizers. It can also be granulated for sale as granulated superphosphate or granular mixed fertilizer.



• To produce granulated superphosphate, cured superphosphate is fed through a clod breakersuperphosphate is fed through a clod breakerand sent to a rotary drum granulator where steam, water, and acid may be added to aid in ygranulation. Material is processed through a rotary drum granulator, a rotary dryer, and a

t l d i th d trotary cooler, and is then screened to specification. Fi ll it i t d i b d b lk f i t• Finally, it is stored in bagged or bulk form prior to being sold.



Triple Superphosphate Production

• Triple superphosphate provides a highTriple superphosphate provides a high concentration of phosphorous.

• Two processes have been used to produce triple p p psuperphosphate: – run-of-the-pile (ROP-TSP) and – granular (GTSP).

• GTSP yields larger, more uniform particles with improved storage and handling properties than ROP-TSP.




• Most GTSP material is made with the Dorr-Oliver slurry granulation process. This process is similar to that for g p pnormal superphosphates with the major exception being that phosphoric acid is used instead of sulfuric acid. In this process, ground phosphate rock or limestone is p , g p preacted with phosphoric acid in one or two reactors in series. The reaction is: Ca5F(PO4)3+ 7H3PO4 + 5H2O →Ca5F(PO4)3+ 7H3PO4 + 5H2O →

5Ca(H2PO4)2•H2O +HF• The phosphoric acid used in this process has a relatively

low concentration (40% P O ) The lower strength acidlow concentration (40% P2O5). The lower strength acid maintains the slurry in a fluid state during a mixing period of one to two hours. A small sidestream of slurry is continuously removed and distributed onto driedcontinuously removed and distributed onto dried, recycled fines in a granulator, where it coats the granule surfaces and builds up its size.


• Granules are then dried in a rotary dryer, elevated and passed through screens to p geliminate oversize and undersize granules.

• Oversize granules are crushed and sent back to the first screen while undersize ones are sentthe first screen, while undersize ones are sent into the emission control systems.

• The granules within the size range of the d t th l d d t d i iproduct are then cooled and stored in a curing

pile where the reaction is completed. • Particulates from the rock handling, drying,Particulates from the rock handling, drying,

screening, cooling, and storing processes are typically controlled with cyclones and bag houses and off-gases from the reactorhouses and off gases from the reactor, granulator, and cyclones and bag houses are typically treated with wet scrubbers.


Potassium Fertilizer ProductsPotassium Fertilizer Products

• Potassium chloride (muriate)Potassium chloride (muriate) • Potassium sulfate

P t i i lf t• Potassium magnesium sulfate• Potassium hydroxide• Potassium nitrate


• Potassium Chloride (60 to 62% K2O), – also referred to as muriate of potash Nearly two-also referred to as muriate of potash. Nearly two

thirds is used for direct application, and the remainder is used in granulating processes or bulk blending of mixed fertilizersmixed fertilizers.

– It is available in four particle sizes: fine, standard, coarse and granular. The fine-size material is used primarily for liquid suspensions Standard coarse andprimarily for liquid suspensions. Standard, coarse and granular sizes are used for granulating processes, bulk blending and direct application.

– Potash varies in color from pink or red to whitedepending on the mining and recovery process used. White potash, sometimes referred to as soluble potash, is usually higher in analysis and is used primarily for making liquid starter fertilizers.


• Potassium sulfate (50% K2O), – also referred to as sulfate of potash, is used to a

limited extent on crops such as tobacco, potatoes and a few vegetable crops where chloride from potassium g p pchloride might be undesirable. Potassium sulfate may also be source of sulfur when sulfur is required.

O• Potassium magnesium sulfate (22% K2O), – also known as sulfate of potash magnesia, is used for

both direct application and in bulk blendingboth direct application and in bulk blending, particularly where magnesium is needed. If may also be used as a source of sulfur.


• Potassium hydroxide, l k ti t h i d t li it d– also known as caustic potash, is used to a limited

extent in the production of liquid mixed fertilizers. The present cost of producing potassium hydroxide has limited its use in the fertilizer industry, even though it is a very desirable product due to high solubility and low salt indexlow salt index.

• Potassium nitrate (44% K2O), – also known as nitrate of potash, is being used on highalso known as nitrate of potash, is being used on high

value crops such as celery, tomatoes, potatoes, leafy vegetables and a few fruit crops. It has a low salt index and provides nitrate N which may be desirableindex and provides nitrate N which may be desirable for these specialty crops. Production costs have limited general use for most agronomic field crops.



Production ProcessProduction Process

C dHCl NH4Cl

Co-product Hydrochloric acid Ammonium chloride

H2 SO4 K Cl NH4 NO3

Raw materials

Mannheim Chemical Process Double Decomposition Process

Sulfuric acid Potassium Chloride Ammonium Nitrate

Specialty Fertilizers

K2SO4Potassium Sulphate

KNO3Potassium Nitrate


Specialty Fertilizers p

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10 - Fertilizers Industry