Abstract: A method for manufacturing abrasive tumbling media comprising discrete abrasive particles having a preselected size and shape made by firing a formed mixture primarily comprising a particulate ceramic material, which method comprises adding at least 10% of hollow ceramic microspheres to said mixture prior to firing to obtain particles having a final fired bulk density below 65 lbs/ft..sup.3. The ceramic material preferably comprises at least 30 percent clay and the hollow microspheres have a shell consisting essentially of from 58 to 65 weight percent silica and from 28 to 33 percent by weight alumina, a shell thickness of about 10% of the diameter of the microsphere and an average particle size of from about 50 to 100 microns.

Abstract: The present invention provides a method for manufacturing light weight abrasive tumbling media made up of discrete abrasive particles desirably exhibiting an essentially uniform size and shape which comprises adding at least 15%, and preferably 20% by weight of a naturally occurring or synthetically produced metal carbonate to a ceramic/clay based formable mixture prior to firing to obtain particles having a final fired bulk density below 65 lbs/ft.sup.3. Such a carbonate may desirably be selected from the group consisting of calcium carbonate, lithium carbonate, magnesium carbonate, zinc carbonate or compounds containing a predominant amount of one or more of these carbonates.