CH1019 Chemical Process Technology

Lecture4b

Chapter3Fer0lizerIndustries

BalasubramanianSAssistantProfessor(OG)DepartmentofChemicalEngineering

Chapter3 FERTILIZERINDUSTRIES

Nitrogenindustries

Phosphorousindustries

Potassiumindustries

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2

Overview of topics

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3

Chapter3 FERTILIZERINDUSTRIES

Nitrogenindustries

Phosphorousindustries

Potassiumindustries

1

2

Overview of topics

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3

Fertilizer industries – Phosphorous

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Phosphorousinelementalformandinitsmany

productsisderivedfromcommercialdepositsof

phosphaterockinthemineralformFluorapa0te

[Ca10(PO4)6F2].

Fertilizer industries – Phosphorous

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Majorproductsofphosphateindustryare:

-  Phosphorous

-  Phosphoricacid

-  Ammoniumphosphate

-  Nitrophosphate

-  Calciumphosphate

-  Sodiumphosphate

-  Triplesuperphosphate

Fertilizer industries – Phosphorous

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PhosphorouscontentofrockisexpressedaspercentageP2O5

Manufacturingmethods:

-  Produc0onofelementalphosphorous,phosphorouspentoxide,and

phosphoricacidbyelectricfurnacemethod.

-  Produc0onofphosphoricacidandchemicalferi0lizerfrom

phosphaterockbystrongacidprocess.

-  Produc0onofphosphorousacidbyHCLleaching

Fertilizer industries – Phosphorous

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PhosphorouscontentofrockisexpressedaspercentageP2O5

Grinder

Produc0onofphosphorousacidbyHCLleaching

Fertilizer industries – Phosphorous

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Majorstepsintheprocess

-  Grindingthephosphaterock

-  DissolvingpowderedphosphaterockinHCl

-  Removal(orwashing)offumesofCO2,HFandHClinseriesofmixer/

thickener.

-  Extrac0onofH3PO4andrecoveryofHClinseriesofevaporators

(Mul0pleeffectevaporators)

-  Concentra0onofH3PO4

-  RemovalofCaCl2aswasteaberextrac0on

Fertilizer industries – Phosphorous

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ManufactureofSuperphosphateandTriplesuperphosphate

Superphosphate–madebyreac0ngphosphaterockwithsulfuricacid

Triplesuperphosphate-madebyreac0ngphosphaterockwith

phosphoricacid.

The phosphorus content of triple superphosphate (17 - 23% P; 44 to 52%

P2O5)isthereforegreaterthanthatofsuperphosphate(7-9.5%P;16to22%

P2O5). It is produced in granular and nongranular form and is used both in

fer0lizerblends(withpotassiumandnitrogenfer0lizers)andbyitself.

Fertilizer industries – Phosphorous

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ManufactureofSuperphosphateandTriplesuperphosphate

AmajoruseofTSPisinsitua0onswhereseveralsolidfer0lizersareblended

together for broadcas0ng on the soil surface or for applica0on in a

concentratedbandbeneaththesurface.Itisalsodesirableforfer0liza0onof

leguminouscrops,suchasalfalfaorbeans,wherenoaddi0onalNfer0liza0on

isneededtosupplementbiologicalNfixa0on.

Fertilizer industries – Phosphorous

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ManufactureofSuperphosphateandTriplesuperphosphate

Cyclone

Cyclone

Sulfur Industries

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References

1.  DrydenC.E,OutlinesofChemicaltechnology–forthe21stCentury,3rdedi0on,East-WestPress(2004)

2.  Aus0nG.T,Shreve’sChemicalProcessIndustries,5thedi0on,McGrawHillInterna0onaledi0ons(1984)