Investigation into the Emerging Issue of Fluorapatite Formation

Fluorapatite is a crystalline compound of calcium phosphate incorporating fluoride ions in its structure. Crystals are hard and highly insoluble within the normal range of potable waters. Formation of the compound is accelerated by an increase in temperature and this study was commissioned as a result of problems experienced with fluorapatite scale in heating equipment, notably domestic boilers.
The study identifies water characteristics that influence fluorapatite formation and maps areas where fluorapatite has been observed in the UK to date and areas that are considered to be at risk should fluoride dosing be introduced in the future.
The report includes a simple Excel utility that allows water companies to review the risk of fluorapatite precipitation for the specific water quality prevailing in their supply areas. The report includes a number of methods of reducing the risk of fluorapatite formation.

Fluorapatite formation risk model

Appendix