BASIC ALUMINUM SULFATE FORMED AS A METASTABLE PHASE AND ITS TRANSFORMATION TO GIBBSITE

Abstract

The metascable nature of basic aluminum sulfate with respect to gibbsite in the systems used is shown in two-dimensional diagrams. When the ion-activity product (H)²(SO₄) is less than 10^−9.3, the basic aluminum sulfate is metastable with respect to gibbsite, which was the case in the systems investigated. Seeding these systems with gibbsite induced the dissolution of basic aluminum sulfate and growth of gibbsite crystals took place. The SO₄ ions did not diffuse out of basaluminite when it was suspended in H₂O.