Abstract: A method of physically and chemically altering asbestos which comprises mixing the asbestos with a selected metal and reacting the mixture to form an end product including slag, in which the asbestos has been altered allowing its safe disposal or its formation into useful products.

Abstract: A method of forming an article of silicon nitride is disclosed. A complex shape of an article is formed in a molding material which may be liquified by heating. A porous shell is formed about the shaped molding material with a refractory ceramic material which loses its structural strength when heated to a high temperature. The molding material is removed from the porous shell and a silicon metal slip is cast into the vacated volume. The silicon metal of the slip is nitrided at a temperature which is also effective to destroy any structural strength of the refractory ceramic material forming the porous shell. The weakened porous shell is removed from the nitrided article to produce the final article.