The Effects of pH on the Flocculation of Quartz Aqueous Suspensions

The effects of pH on the flocculation of quartz aqueous suspensions containing Ba2+, Fe3+ or Cu2+, respectively, were investigated by means of electrokinetic measurements. The violent flocculation takes place in the characteristic range of pH with respective cation involved. The calculation of the potential energy between approaching quartz particles indicates that the violent flocculation is readily explained, not by the decrease of electrical repulsion, but by the consideration of an attractive force other than van der Waals attraction.