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What is Gypsum & What is Phosphogypusm?Gypsum chemically known as “Calcium Sulfate Dihydrate,” Gypsum containsCalcium, Sulfur bound to Oxygen and ater! Gypsum is an abundant " acolourless mineral " white minerals sometimes tinted by impurities, found in bedsas an e#aporate and takes forms including alabaster $ a material used indecoration, construction, manufacture of plaster of %aris, cement, paint, schoolchalk, glass, and fertili&er as far back as ancient 'gypt!

%hosphogypsum means Calcium Sulfate and by$products produced by thereaction of Sulfuric (cid with %hosphate )ock to produce phosphoric acid!

Which one do you prefer between these two and why?

e prefer the %hosphogypsum because it refers to the Gypsum formed as a by$product of the production of fertili&er from phosphate rock! *t is mainly composedof Gypsum +CaSO! -he latter is called %hosphogypsum, which contains morewater than .atural Gypsum, is more acidic and has more

impurities!%hosphogypsum is generated from /ltration process in phosphoric acidplants where insoluble Gypsum +and other material is separated from theproduct i!e! phosphoric acid as e0ciently as possible! -he 1uality 2 1uantum of %hosphogypsum generation depends upon the 1uality of the phosphate rock,process route used to produce phosphoric acid, calcium sulphate generated in di$hydrate +CaSO3!454O form!

What are the main dierences between Natural Gypsum and Phosphogypsum?

 -he .atural Gypsum and %hosphogypsum are two kinds of Gypsum, regardless of ha#ing the same chemical formulas, ha#e di6erent structures7 the .aturalGypsum has a less distinct crystalline structure, and %hosphogypsum has a well8de/ned crystalline structure with the ma9ority of rhombic and hexagonal shapecrystals! -his indicates that it has a more complex composition than naturalgypsum!What are the types of associated additives present in Phosphogypsumand in Natural Gypsum?

ChemicalComposition

Natural Gypsum(In Wt. %)

PhosphogypsumTaken

From Plant’sPipe 

Phosphogypsum(In Wt. %)

CaSO3:454O 8 ;3!CaSO3:

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Chemicaland ineralogical Compositionof .atural Gypsum,%hosphogypsum -akenrom %lantHs %ipeand %urified %hosphogypsum

What is the eect of associated additives such as P2O and !oisture onthe "uality and performance Phosphogypsum & Gypsum?

 -he e6ect of phosphate +%4O> content on the structure of two series of bioacti#eglasses in the 1uaternary system SiO48.a4O8CaO8%4O>  was studied! -he /rstseries +* was a simple substitution of %4O>  for SiO4 keeping the .a4O7CaO ratio/xed +

the orthophosphate +%O3@$, therefore as %4O> was added the .a4O andCaO content was #aried to pro#ide su0cient .aF  and Ca4F  cations to chargebalance the orthophosphate present! -he glass network connecti#ity +.C wascalculated for each glass and a modi/cation for the presence of a separate %4O>phase was included +.CI! @