Fluoride is a flux and a mineralizer for clinker, improves burnability and promotes alite formation and clinker reactivity.
Clinker mineralization with fluoride facilitates the production of clinker with alite contents up to 80 %.
On the one hand, fluoride increases the rate of alite formation in clinker, on the other hand it also stabilizes alite at lower temperatures. Overall, these effects of fluoride on the alite formation reaction improve clinker burnability which can industrially be exploited to reduce specific thermal energy consumption of clinker burning or it can be used to burn clinker with superior alite contents. The technology of clinker mineralization was implemented by different cement manufacturers end of the last century to increase cement volumes and reduce production cost in suitable markets. Typically natural fluorspar was used a source for fluoride but with the option to use HiCAl products, a very cost competitive alternative fluoride source is now available.
Beside the material supply, Regain provides technical support for the implementation of clinker mineralization.
Laboratory burnability testing was done on raw meals doped with HiCAl. Therefore small quantities of HiCAl 40 were added to raw meal to adjust different levels of fluoride. After burning the mixes in a laboratory kiln at temperatures between 1350 and 1450 °C, the remaining free lime in the burned clinker was measure and used to quantify the effect of the fluoride input from HiCAl products on burnability.
As can be seen in the following chart, increasing fluoride in clinker has a very beneficial impact on the remaining free lime level in the burned clinker samples: