Interesting role of B2O5 on stabilisation of C2S.
Ted Krapkat
Hello Michael,
Are you referring to boron stabilisation of C2S in steel slag or in high belite cements?
I know that B2O3 is used to dope stainless steel slags to stabilise Beta-C2S and so prevent its transformation into Gamma-C2S. The transformation of Beta to Gamma-C2S is accompanied by a large volume change in the crystal lattice, resulting in the disintergration of the ß-C2S crystals which causes the slag to become very dusty and hard to handle.
In the case of cement, B2O3 can only be used in clinkers with a high belite content since it not only stabilises the ß-C2S it also actively promotes the decomposition of C3S into stabilised ß-C2S and free lime, which is not desirable for alite cements such as OPC. In this regard, the action of boron is similar to that of phosphorus, and like phosphorus boron has an adverse effect on OPC setting times, even at concentrations as low as 0.05% B2O3.
Best Regards,
Ted.
Silastman
Dear Ted!
Thanks for the advice. I know these basics, but need the literary sources. This is really a request for stabilization of Metallurgists refining high calcium slag. If you know the literary sources, please provide them.
With respect!
Michael.
Ted Krapkat
Hello Michael,
The following links may be of interest to you in this regard...
http://imim.pl/files/archiwum/Vol4_2010/20.pdf
http://slag-valorisation-symposium.eu/images/papers/ps1_3_Huang.pdf
http://www.globalslag.com/magazine/articles/456-borate-stabilisation-of-air-cooled-slags
http://www.linkedin.com/groups/Stabilization-CaOSiO2-MgO-Slags-Sustainable-4082748.S.225814913
There is also a US patent based on this process...
http://www.google.com/patents/US4655831
I hope this helps you...
Best Regards,
Ted.