The development of reagent strategies for the flotation of boron miner
als requires an understanding of flotation chemistry of reagent/minera
l interactions. The floatability of a typical boron mineral, colemanit
e, was investigated in a microflotation cell by using anionic and cati
onic surfactants as collectors and tannic acid as a depressant. The re
sults obtained with zeta potential measurements together with flotatio
n tests reveal that colemanite is floatable with both anionic and cati
onic surfactants at its natural pH of 9.3. While the floatability of c
olemanite with anionic surfactants decreases with increasing pH, that
with a cationic surfactant exhibits a maximum at pH 10.2, indicating t
he major role of electrostatic interactions in the system.