Patent ID: 6995105

Claim:
A method of fluidizing or retarding the setting of a refractory composition comprising alumina cement comprising: preparing a refractory composition by admixing a refractory composition comprising alumina cement with a water-soluble copolymer wherein said water-soluble copolymer is prepared from at least two monomers selected from the group consisting of: a) 5–90% by weight of a monomer (mixture) of the formula I where R 1 ═H or —CH 3 , R 2 and R 3 are each, independently of one another, H or —COOH and R 4 ═H, —COOH or —CH 2 COOH, or R 2 and R 4 , together form a group or R 3 and R 4 together form a group, where R 3 and R 4 are different and are each H or —COOH when R 1 ═H and R 2 =—COOH, R 3 =−COOH and R 4 =—COOH when R 1 and R 2 are each H, R 3 and R 4 are different and are each H or —COOH when R 1 =−CH 3 and R 2 =—COOH, R 2 and R 4 together form a group, when R 1 and R 3 are each H or R 1 ═CH 3 and R 3 ═H, and R 3 and R 4 together form a group, when R 1 and R 2 are each H, or a corresponding alkali metal, alkaline earth metal or ammonium salt thereof, or b) 5–90% by weight of a monomer (mixture) selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid, vinylsulfonic acid, vinylphosphonic acid, stryrenesulfonic acid, 2-acrylamido-2-methylpropionic acid and their alkali metal, alkaline earth metal and ammonium salts and sodium methallysulfonate, or c) 5–90% by weight of a monomer (mixture) selected from the group consisting of acrylic acid, methacrylic acid, N-vinylpyrrolidone, N, N-dimethylacrylamide, acrylamide and methacrylamide and their corresponding alkali metal, alkaline earth metal and ammonium salts, as fluidizers or setting retarders for refractory compositions comprising alumina cement; wherein the water soluble copolymer is added in an amount sufficient to impart a fluidizing effect or to retard the setting of the refractory composition, wherein said refractory composition has a particle size distribution of 35% of from 1–5 mm, 30% 0.1 to 1 mm, and 35% less than 0.1 mm, and wherein said refractory composition further comprises from 1 to 100% by weight, based on the solids content of the refractory composition, of a ceramic binder that is an aluminum oxide compound.