We are using it as a retarder Ted, can you comment on this one?

Dear Mr.Ted & Mr.Norew,

Chemical gypsum or industrial byproduct Phosphogypsum contains impurities of free phosphoric acid,phosphotes,fluorides and organic matter.It is essential to remove these impurities to use the chemical gypsum for controlling the cement hydration.Lime treatment is use to get rid of free phosphoric acid impurities with the chemical treatment by making them inactive.The neutralized gypsum will be used for controlling the cement hydration and improve early age strength development of cement.

I do hope this will clarify your query.

With regards,

Raj Sahu,

Hello Raj,

Thank you. So, is it safe to say that it is better to use lime-treated gypsum than the ordinary one?

Which is a better retarder?

Hello Norew,

Do you know the gypsum content of this stuff? Also, do you know what else may be in it?

Regards,

Ted.