Process for producing an environmentally acceptable abrasive product

Abstract

A method and apparatus of reclaiming hazardous inorganic wastes to produce an environmentally benign abrasive for use in loose grain processes, as a coated or bonded abrasive, or as a polishing grain. A tough and useful abrasive, with a MOH hardness of 7 to 8, is manufactured from emission control dusts of the aluminum industry or sludges from other industries, and may include small amounts of lead and cadmium oxides as toughening agents. The abrasive particles are sized by air sifting or by water sedimentation separating methods. The process for the manufacture of abrasive material comprises the steps of removing soluble salts from a waste stream by hot water extraction; using a computer matrix to group the waste stream into different batches for mixing with other glass-making materials to form a batch mixture; oxidizing the organic compounds contained in the batched mixture; melting the batch mixture to form a glasseous substance; and fritting the glasseous substance to form the abrasive. The process preferably uses a glass melter that will oxidize organics; a scrubber to recapture vaporized heavy metal oxides and particles of the glass-making materials; and an oxygen injection system ensure thorough burning of organics. Certain sodium compounds may be added to reduce the melting point of the batch mixture. An abrasive formed by the process of the invention may comprise the following components by weight: 48-56% silica; 18-30% alumina; 6-12% NaO; 6-12% CaO and MgO; 2-4% Fe.sub.2 O.sub.3 ; and 0.1-1% PbO.