Abstract: Lightweight, low density magnesia-based tundish refractory compositions containing from 0.01 to 2.00 weight percent styrofoam beads and up to 5.0 weight percent paper fiber are disclosed. The compositions have excellent rapid heating, thermal insulative, vertical adhesion and deskullability properties. The compositions are useful as a lining applied over the permanent lining of a tundish, such as is used in continuous molten metal casting processes.
Type:
Grant
Filed:
October 23, 1989
Date of Patent:
December 17, 1991
Assignee:
Quigley Company, Inc.
Inventors:
Jung-Jen A. Cheng, Wilfred A. Martinez, Amy P. Hale
Abstract: A form of calcium carbonate, acid-stabilized by the addition to finely divided calcium carbonate of one of a calcium- chelating agent and a conjugate base, such as sodium hexametaphosphate, followed by the addition of a weak acid, such as phosphoric acid, is disclosed. A process for producing this material, and a method for its use in the making of neutral to acidic paper in order to improve the optical properties of the paper are also disclosed.
Abstract: Substantially homogeneous (meth)acrylic acid/itaconic acid copolymers of number average molecular weight of 500 to 7000 are prepared by copolymerizing in aqueous solution 5 to 90 mole percent acrylic or methacrylic acid monomer with 95 to 10 mole percent itaconic acid monomer at 80.degree. to 120.degree. C. in the presence of a polymerization initiator, the acrylic or methacrylic acid monomer and at least half of the initiator being added separately and continuously to the itaconic acid monomer throughout the polymerization period. The copolymers are employed at a level of from about 0.1 to 100 ppm for prevention of alkaline calcium and magnesium scale formation, such as during seawater evaporative desalination.
Abstract: A continuous, monofilamentous, alkali-resistant glass fiber especially useful in cementitious products is conveniently prepared from a glass-forming composition comprising a magnesium silicate such as talc and a calcium carbonate such as limestone. Either the fiber itself or a strand comprising a plurality of the fiber is advantageously coated with an alkali-resistant polymer such as butadiene-styrene to provide additional alkali resistance.