Ted Krapkat:
1.Because Zn causes less C3A to form in the clinker.This means that, for the same gypsum content, the cement paste will take proportionately longer to set
2. There is some evidence that, Zn+2 ions, released during initial hydration, react to form Zn(OH)2, or even complex salts such as calcium hydroxy-zincate, which coat the anhydrous clinker grains and retard further hydration, in a similar manner to ettringite.
The raw mix investigated{researched} by me will constrain 2 % ZnO and 2 % CuO. With ZnO all it is clear. What influence can render CuO on processes of formation clinker and hydrations of cement?
PS Our clinker does not contain ?3?. It contain sulphated phase C3A3CaSO4, therefore reduction of quantity{amount} ?3? it is impossible and retard of hydration is the reason to coat the clinker grains by calcium hydroxy-zincat. Blocking of
clinker grains
is possible if the film on it's surface is insoluble. Zn(OH)2 is Insoluble, but I do not know soluble or not
calcium hydroxy-zincat?
The raw mix investigated{researched} by me will constrain 2 % ZnO and 2 % CuO. With ZnO all it is clear. What influence can render CuO on processes of formation clinker and hydrations of cement?
Hello Silastman,
The links below cover your frst question I believe;-
"Role of Minor lements in Cement anufacture and Use", by Javed Bhatty. (Portland Cement Association.) http://www.gcc-cap.com/downloads/Role%20of%20Minor%20Elements%20in%20Cement%20Manuf%20and%20Use.pdf
and...
"Effect of CuO on the Formation of Clinker Minerals and the Hydration Properties" http://trid.trb.org/view.aspx?id=987424
PS Our clinker does not contain ?3?. It contain sulphated phase C3A3CaSO4, therefore reduction of quantity{amount} ?3? it is impossible and retard of hydration is the reason to coat the clinker grains by calcium hydroxy-zincat. Blocking of clinker grains is possible if the film on it's surface is insoluble. Zn(OH)2 is Insoluble, but I do not know soluble or not calcium hydroxy-zincat?
Unless you are talking about cement instead of clinker, I'm not sure what you mean here. C3A.3CaSO4.32H2O is ettringite, which is produced during cement hydration by reaction of C3A and gypsum in the presence of water. There would not be any ettringite in fresh clinker.
In any case, calcium hydroxy-zincate is indeed insoluble enough to coat the grains of clinker minerals, retarding hydration of not only C3A but C3S (and no doubt C2S) as well.
Regards,
Ted.
THANKS TED !
YOUR HELP IS INVALUABLE.
YOU VERY GOOD EXPERT !
Unless you are talking about cement instead of clinker, I'm not sure what you mean here. C3A.3CaSO4.32H2O is ettringite,
Ted
It's not usial moment for you. Ettringite is product of hydration. Sulpho aluminate of calcium - C3A3 CaSO4 or C4A3SO3 (full 3CaO 3Al2O3 CaSO4) is clincer's mineral. Look Cement Chemystry by H.F.D. Taylor. Chapter X (10.3.2). I making new low temperature Portland cement without C3A & C4AF.