US 6,311,522 B1Granted

Process for casting and forming slag products

AssigneeSlaytech Inc.

InventorsRichard Berry, Brian Reeves

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Abstract

The present invention relates to a process and apparatus to cast and form slag directly from the molten state into crystalline or amorphous products suitable for use as decorative and structural building and construction materials. Molten slag and additives are refined at high temperature in a treatment furnace for a period of hours. The eventual entrapped gas content is controlled using a variety of methods, such as vacuum pressures and bottom stirring with inert gas. The molten slag is cast directly into moulds, and these moulds form the slag into any shape desired. The formed products are immediately introduced into a heat treatment furnace at temperatures at or above the glass transition temperature (GTT) for the case of crystalline products, or just below the GTT for amorphous products. The product is thermally cycled over a period of hours to relieve thermal stresses during cooling to ambient temperatures. If desired, the product can be coated using enamel or glaze and cured in another furnace, or metal plated.

Claims16

Dependent claims

A process for controlled casting and forming of structural and decorative construction materials consisting of the following steps:

(a) first waste oxides, either molten or solidified, are delivered to a slag treatment vessel;
(b) additives selected from the group consisting of other industrial by-products selected from the group consisting of second waste oxides different than the first waste oxides, slag types, bag-house dusts, scrap glass, silica sand, and specialty ceramic materials selected from the group consisting of silica, zirconia, alumina and others are added in an amount equal to 5 to 35% by weight of the aforementioned first waste oxides;
(c) the contents of the slag treatment vessel are heated to a fining temperature of between 1200° C. to 1700° C. to dissolve all the additives and first waste oxides into a melted oxide;
(d) the melted oxide is held at the fining temperature for a period of one half (½) to five (5) hours to help burn off volatiles and control the rate of dissolved gas formation;
(e) the melted oxide is then cast into moulds at a controlled casting temperature to directly form a cast crystallized product without intermediate formation of a glass;
and then
(f) the cast crystallized product is immediately conveyed through one or more thermal treatment furnace for a heating/cooling cycle of finite period of time to relieve thermal stresses in the cast crystallized product.

4 more elements

Dependencies are inferred from the claim text.