Kennecott Corporation

The Carborundum Company

Paul Cichy

Robert J Seider

Thomas Bruce Walker

The present invention provides a process and apparatus for the production of refractory oxide materials having high fusion points. By high fusion points is meant melting points greater than 2400.degree. C. The process of the present invention comprises the steps of:

Process for casting fused refractory oxides having high melting points

The invention provides a method wherein alumina-containing slag from melting of spent alumina catalyst material is transported to a second furnace for finishing to satisfactory temperature, composition and quantity for casting as an abrasive material or cast refractory. In one embodiment of the invention, the molten alumina slag material is cast into an inclined trough for direct delivery from the spent catalyst furnace to the abrasive or refractory furnace for finishing.

Recovery of heavy metals from spent alumina

The invention relates to the recovery of precious metals which is accomplished by melting an alumina-containing spent catalyst having therein a minor amount of a precious metal. The melted alumina containing carrier material is heated to about 2100.degree. C. in an electric furnace. The alumina material is poured from the furnace for utilization in abrasives manufacture. The precious metal collects in the bottom of the furnace and is either poured off and allowed to solidify or allowed to solidify in the furnace. In one embodiment of the invention, the steps of melting spent catalyst and heating to form a molten mixture is repeated a multiplicity of times with pouring off of the molten carrier material. As a multiplicity of meltings and pourings are carried out, gradually there is an appreciable accumulation of the precious metals in the bottom of the furnace.

Recovery of precious metals from spent alumina-containing catalysts

Apparatus for casting fused refractory oxides having high melting points

A fused abrasive grain, useful for inclusion in coated abrasives and bonded abrasives, consists essentially of alumina; titanium oxide containing from about 0.42 to about 0.84% titaniun, by weight of the abrasive grain, present as a reduced titanium oxide having an average oxidation state lower than in Ti.sub.2 O.sub.3 ; from about 0.05 to about 0.3% by weight carbon; from about 0.02 to about 0.1% by weight Na.sub.2 O; and from 0 to about 0.1% by weight total of calcium and silicon oxides. The grain before roasting has a gain on ignition of from about 0.4 to about 0.7% by weight, and is produced in an electric furnace by fusing high-purity titania, alumina containing Na.sub.2 O as the only significant oxide impurity, and carbon, followed by crushing and roasting the fused grain.

Fused aluminum oxide abrasive grain containing reduced titanium oxide

A fused abrasive grain, useful for inclusion in coated abrasives and bonded abrasives, consists essentially of alumina; titanium oxide containing from about 0.42 to about 0.84% titanium, by weight of the abrasive grain, present as a reduced titanium oxide having an average oxidation state lower than in Ti.sub.2 O.sub.3 ; from about 0.05 to about 0.3% by weight carbon; from about 0.02 to about 0.1% by weight Na.sub.2 O; and from 0 to about 0.1% by weight total of calcium and silicon oxides. The grain before roasting has a gain on ignition of from about 0.4 to about 0.7% by weight, and is produced in an electric furnace by fusing high-purity titania, alumina containing Na.sub.2 O as the only significant oxide impurity, and carbon, followed by crushing and roasting the fused grain.

Oxide refractory materials (for example, aluminazirconia mixtures) can be cast to have an extremely fine crystal structure, by casting a melt of oxide refractory materials onto a non-reactive, non-melting particulate solid cooling media of a material other than that of the oxide refractory material (for example, steel spheres having a size ranging from about 5 to about 60 millimeters). The casting takes place within a solidification chamber having an opening in its lower end, through which the cooling media and solidified oxide refractory melt can be removed. According to one embodiment, the opening in the lower end of the solidification chamber is either temporarily completely blocked by a base, which is periodically removed to allow the recovery of cooling media and solidified oxide refractory melt, or continuously partially blocked by the base, so that the cooling media and solidified oxide refractory melt can be continuously recovered from the solidification chamber. According to another embodiment, no base at all is required, but the continuous discharge of cooling media and solidified oxide refractory melt is controlled by the angle of inclination of the cylinder which constitutes the solidification chamber. The solidified material, when crushed and graded, has exceptional utility as an extremely tough abrasive grain.

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Buffalo, NY, United States of America

Paul Cichy