Kaolin: an important role in boilers

Sibelco pure FLOWGARD® kaolin is the answer to prevent the boiler’s fireside system against the slagging, fouling and corrosion that usually occurs as a result of burning fuels containing high percentages of volatile alkalis such as agro-waste, biomass, coal, MSW, pellets, wood and more.

Alkali metals sodium (Na), potassium (K), and calcium (Ca) found within these fuels are released into the flue gas as vapor. The vapor condenses onto fly ash particles and heat exchanger surfaces as liquid salts of sulfur, chlorine or similar particulates which in turn traps solid fly ash particles onto the cooler surfaces.
Complex reactions then occur, including dissolution, sulfation, and sintering which ultimately leads to slagging and fouling.

Sibelco kaolin works as an alkali sorbent, by incorporating them into compounds that remain solid at boiler temperatures. At the end of the process, the alkali compounds exit the boiler as fly or bottom ash.


Slagging, fouling and corrosion problems can be easily managed or completely eliminated from the process, increasing boiler availability and its overall performance!

This effectively allows for the combustion of a mix of lower cost, opportunity fuels that are otherwise difficult to use, making it possible to increase boiler efficiency and power generation at a lower fuel cost.


Our high purity kaolin has alumina content of ~35%, being incredibly effective as additive for boiler customers! It is manufactured in our plants of Cornwood (UK), Kingsteignton (UK) and Hostun (France).

Technical data sheet
How can we help you?

To know more about our kaolin products, please contact us at renewables@sibelco.com