PROCESS TO PRODUCE AN ALPHA-ALUMIN PRODUCT, PROCESS TO PRODUCE A GAMMA-ALUMIN PRODUCT, ALPHA-ALUMIN PRODUCT, GAMMA-ALUMIN PRODUCT, COMPOSITION AND COATED ABRASIVE ARTICLE

摘要

A process for the formation of high alumina products using electrophoretic deposition on a membrane (15). In the process of the invention, a liquid dispersion comprising from about 0.1 to about 40 weight percent aluminium oxide monohydrate and optionally a dissolved metal-containing sintering aid is formed and placed into an electrophoretic cell having an anode (10), a cathode (5), and at least one membrane (15) positioned between said anode (10) and cathode (5). A D.C. current is applied between said anode (10) and cathode (5) causing the deposit of a precipitate of concentrated aluminium oxide monohydrate material onto the membrane (15) and the cathode (5). The deposit may then be removed from the membrane (15), dried and fired, with or without a separate calcining step, to produce an alumina product.