Electrokinetic properties of a series of boron minerals, i.e., coleman
ite, ulexite, inderite, and tunellite, are investigated using the micr
oelectrophoresis technique. Colemanite exhibits an isoelectric point a
t pH 10.5. Ulexite, inderite, and tunellite yield practically no isoel
ectric point in the pH range of 7 to 11. While ulexite remains negativ
ely charged, inderite and tunellite show positive charges in the pH ra
nge studied. The potential determining ions for these minerals are the
constituent lattice cations, Ca2+, Mg2+, and Sr2+, and the anion, B4O
72-. The H+ and OH- ions which indirectly control the ratio of HCO3-/C
O32- are also the potential determining ions for the hydrated boron mi
nerals studied. The electrokinetic results generally support the adsor
ption of oppositely charged flotation collectors on boron minerals thr
ough electrostatic attraction. (C) 1995 Academic Press, Inc.