General Refractories Company

Franz J Brodmann

Ronald Staut

Richard D Varker

A fast response ceramic ignitor which is particularly adapted for use with household current as a replacement for gas pilot lights, the ignitor being formed from pure lanthanum chromite, or lanthanum chromite which has been doped with combinations of niobium, magnesium, or strontium ions in quantities sufficient to provide desired electrical resistivity characteristics.

Ceramic ignitor

A method of decreasing the electrical resistivity of a rare-earth chromite material by substituting bivalent metal ions for some of the chromium or rare-earth ions therein. The method includes applying a solution containing the bivalent metal ions to the rare-earth chromite under vacuum conditions, drying the solution on the chromite, and diffusing the bivalent metal ion into the rare-earth chromite by firing the chromite in a controlled atmosphere.

Method of modifying electrical properties of rare-earth chromite material

A method of increasing the magnesia content in dolomite sinter produced from dolomite. Crushed dolomite is calcined to form a physical mixture of particulate magnesium oxide (MgO) and calcium oxide (CaO) and the mixture is hydrated to develop a size differential between the calcium hydroxide and the magnesium hydroxide. The hydroxides are dried without dehydration and separated into two component portions on the basis of size. One portion of the mixture is rich in Ca(OH).sub.2 and the other is rich in Mg(OH).sub.2. The portion of the mixture primarily comprised of Mg(OH).sub.2 is then calcined to form the synthetic sinter.

Process for producing synthetic magnesite - dolomite sinter

This invention relates to the manufacture of lime-silica bonded structural materials particularly suitable where structural materials having thermal insulation properties are desired. More specifically, the invention relates to new and improved methods of manufacturing lime-silica bonded structural materials having high modulus of rupture and high compressive strength.

Method for making lime-silica insulation from perlite

Alkali resistant glass fibers and mineral wool are produced from perlite by heating perlite ores until the melt viscosity is under 15 poise and impinging a stream of the melt with a gas at from 80 to 100 psig to produce the fibers.

Alkali resistant perlite - CaO vitreous fibers

Perlite reduced to a particle size of less than 200 mesh in a binder of aqueous sodium ligno-sulfonate is expanded while suspended in a gaseous medium in a fluidized state at temperatures ranging from 1800.degree. to 2200.degree.F. for a period of 30 to 60 seconds. The resultant microspheres have excellent physical properties and are suited to use as fillers for resins.

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Philadelphia, PA, United States of America

Franz J Brodmann