Electrokinetic behaviour of asbestos minerals as a function of aging time in water

Abstract

The electrokinetic behavior and dissolution in water of several ferromagnesium silicates were studied as a function of their aging time. The particular magnesium silicates studied were asbestiform and nonasbastiform varieties of serpentine, and crocidolite, a fibrous member of the amphibole group. Acid treated and untreated samples of the three minerals were studied. Changes in the pH, point of zero charge (pro) and electrophoretic mobilities were noted for various aging times up to ten weeks for two different (weight/volume) suspensions of these minerals. Concentrations of magnesium, iron and silicon were measured in the leachates at intermediate time intervals. It was observed that the pzc’s of these minerals are variable quantities and are dependent, on the history of the minerals, on the ionic constituents of the suspensions and hence, on the pH of the suspensions. It was also noted that the dissolution of the magnesium silicates is a zero order kinetic, reaction and that such a study can throw more light on the disputed structure of chrysotile.