The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1994
Filed:
May. 29, 1992
Wolfgang Becker, Dusseldorf, DE;
Fred Brunk, Hattingen, DE;
Dr. C. Otto Feuerfest GmbH, , DE;
Abstract
The invention relates to a material which is refractory, porous, resistant to fluorine-containing gases, stable in its volume and heat-insulation, particularly in the form of formed bricks, for a refractory, heat-insulating lining in electrolytic cells, in which metal aluminum is extracted by electrolysis from aluminum oxide dissolved in a fluoride melt; the material has an Al.sub.2 O.sub.3 content of over 50 wt % and a TiO.sub.2 content of 2.5-10 wt % and during the action of fluorine-containing gases at temperatures between 700.degree. and 1000.degree. C. in the area of the material exposed to the fluorine gas, on free surfaces, particularly at the boundary surfaces of intergranular hollow spaces, needle-shaped TiO.sub.2 crystals and/or TiO.sub.2 -containing crystals are formed, growing without regularity into the porous space. The invention furthermore relates to a method for the manufacture as well as the use of the refractory material.