Sedimentation test of metal hydroxides: hydrodynamics and influence of pH

Experimental data obtained from sedimentation tests of metal hydroxide susp ensions have been discussed considering the compression zone surface observ ed directly and that deduced joining the critical points estimated from som e sedimentation runs, when plotting the settling rate of the suspension-sup ernatant height versus time. Estimations of the aggregate diameter and the aggregate volume/solids volume ratio (by two independent methods) have also been obtained. The influence of the pH on the hydrodynamics, the aggregate diameter and the aggregate volume/solids aggregate ratio has been studied. (C) 1999 Elsevier Science B.V. All rights reserved.