This document specifies a procedure for the determination of fluorine in copper and zinc sulfide concentrates by sodium hydroxide fusion and fluoride ion selective electrode (FISE) detection. Fluoride ions are leached from the sodium hydroxide fusion and presented to the FISE. Potential interfering ions are masked by the use of a complexing agent and control of solution pH. If the aluminium content in the concentrate is up to a mass fraction of 4,5 %, there is no effect of aluminium in this method. However, if the aluminium content in the concentrate exceeds a mass fraction of 4,5 %, there is a possibility that it can affect the analytical results.

The method is applicable to fluorine in the following ranges:

—          copper concentrates:             mass fraction of 0,008 % to 0,3 %;

—          zinc concentrates:     mass fraction of 0,005 % to 0,1 %.

The results of the trueness test can be found in Annex C.