ALKALI RESSITANT AND ANTI-STICKING REFRACTORY CASTABLES
In cement kiln environment, the volatile sunphate and clorine salts of alkalies (K+, Na+) and other reactive chemicals tend to stick to refractory linning surface and penetrate into material body. This process is especially severe in the cement kilns where alternative fuels are used. This leads to two phenomena:
- Forming sodium- and potassium aluminates with it’s high expansion rate, which cause deterioration of refractory castables body layer by layer;
- In the ereas of high volatile alkalies concentration, a liquid phase forms the build-up of raw materials powder on the surface of refractory castables linning (especially in lower part of preheater).
These phenomena lead to unstable kiln operation and shorter service life of refractor linning.
To resolve this problem, a variety of silicon carbide (SiC) containing refractory castables is now widely used for cement kilns, owing the exelent thermo-mechanical and chemical resistant performances of this material. Novaref’s RD team had furnished our Novacast-SiC and alkali ressitant product serie by using a special alkali reisistant raw materials and fortifying castables matrix using the functional additives to improve the anti-sticking and anti-oxidation performance of our SiC containing refractory castables. These products during high temperature working conditions generate a glazy coating of high silica glass, which prevents SiC from oxidation and refractory linning surface from alkalies salt penetration.
Our products Novacast-30AR for use in in upper part, Novacast-SiC5030, Novacast-SiC50 for use in lower parts of cement kiln preheater, Novacast-SiC30N for use in Nosering Outlet, Novacast-SiC30B for use in Burner Tip – all had proved a reliable and long service life.
