The Dow Chemical Company

John S Lindsey

Walter W Henslee

Stanley J Morrow

Christopher P Christenson

Charles R Whitworth

John N Periard

Hans H Schwantje

There is disclosed a unique substantially non-reactive refractory material suitable for use as a material of construction for various component parts of an electrolytic light metal, particularly magnesium, production cell. The non-reactive refractory material is comprised of a magnesium aluminum spinel. When used in block form the blocks may be joined together by use of a phosphate-spinel mortar.

Magnesium aluminum spinel in light metal reduction cells

Several methods are set forth for preparing polymetallic spinels by coprecipitating two or more metal compounds in a proportion to provide a total of eight positive valences when combined in the oxide form in the spinel crystal lattice. The methods disclosed require coprecipitation of the metals in the hydroxide form or convertible to the hydroxide-oxide form, calcining the coprecipitate, and finally sintering the calcined material at about one-half its melting point or greater, thereby forming a spinel which has a density of greater than 50 percent of the theoretical density of spinel crystal. Also disclosed are techniques for preparing spinels having more than two metals incorporated into the spinel lattice, as well as a separate oxide phase associated with the spinel crystallites, and slipcasting compositions.

Magnesium aluminum spinels

A method for preparing spinel (MgAl.sub.2 O.sub.4) surfaces on alumina or alumino silicate articles or shapes by exposure of the article or shape to molten or vaporous magnesium or magnesium alloy for from two to ten hours under nonpyrophoric conditions.

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Houston, TX, United States of America

John S Lindsey