Purity of gypsum

dear all,

What is the suitable purity of gypsum (CaSO4.2H2O) usded for producing cement . As concidered, SO3 in clinker less than 0.15 % and cost reduction .since gypsum cost is much cheaper than clinker in my area .

thanks,

kothar 

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re Purity of gypsum

Generally Gypsum having purity more than 80% as CaSO4.2H2O is considered suitable for mentaining SO3. If Gypsum having very Low  purity can cause high innsoluble residue in cement and decrease the strenght due to high caly content. However high purity of gypsum ~88.0% is ideal.But u should count C3A in cement before deciding SO3 target.

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re Purity of gypsum

Ideally 60-65 % pure gypsum is good to add up to 5 %. With high purity addition will be low and cement cost will be higher

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re Purity of gypsum

Dear all,

       High purity gypsum required % reduced , So current trend to use 90 % purity gypsum.

  (  45 %   So3 in Gypsum ).Cost of cement balance by addition Fly ash , Lime stone & mixed FGD gypsum.)

 Can replaced % Mineral Gypsum  by FGD gypsum . Or  FGD gypsum is replaced by chemical gypsum.

With regards

GKS

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