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Conversion Technologies International, Inc.

Gerald P Balcar

James R Morano

An environmentally safe abrasive composition which contains at least about 60 weight percent of ferrometalsilicate, at least about 5 weight percent of spinel, and at least about 70 weight percent of crystalline material. This composition has a Vickers hardness of at least about 550 and a density of from about 2.8 to about 4.1 grams per cubic centimeter. It is crystallized in situ from a thermally crystallizable mixture comprising from about 50 to about 75 weight percent of electric arc furnace dust, from about 5 to about 40 weight percent of glass, and at least about 10 weight percent of silica sand.

Abrasive composition

A process for making an abrasive composition. In the first step of this process, from about 50 to about 85 weight percent electric arc furnace dust is mixed with at least about 10 weight percent of silica to prepare a thermally crystallizable mixture; the electric arc furnace dust has a particle size distribution such that at least about 70 weight percent of its particles are smaller than about 20 microns, and it contains from about 35 to about 65 weight percent of at least an iron material selected from iron, iron oxide, and mixtures thereof. Thereafter the mixture is melted by subjecting it to a temperature of from about 2,300 to about 2,900 degrees Fahrenheit to form a glass melt, the glass melt is quenched by reducing its temperature at least 1,000 degrees Fahrenheit in less than about 5 seconds to form a quenched glass, and the quenched glass is crushed by subjecting it to a pressure of at least 1.0 MegaPascal.

Process for making an abrasive composition

Glass beads in accordance with the present invention may be constituted of SiO.sub.2, Al.sub.2 O.sub.3, Na.sub.2 O, K.sub.2 O, BaO, SrO, TiO.sub.2, and CeO.sub.2. The glass of which the glass beads is made will generally contain at least 40% SiO.sub.2 as the network former, from about 10 to about 25% Na.sub.2 O and K.sub.2 O as fluxes, from about 5 to about 25% of BaO and/or SrO as a fracture resistance improvement components, a small amount of Al.sub.2 O.sub.3, and--when made from CRT waste--very small amounts of TiO.sub.2 and CeO.sub.2. The glass beads of the invention are suitable for use as reflective elements in roadway markings and as media in shot-peening metal cleaning procedures.

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Dunkirk, NY, United States of America

Gerald P Balcar