Les Sables Olimag, Inc.

Alcan International Limited

Yvan Huard

Gilles Mathieu

Jay Aota

Raymond Breault

Compositions for refractory materials and methods for providing the compositions are described. A synthetic forsterite-rich refractory sand composition includes a mixture. The mixture includes: a) a carbon bridging agent, the carbon bridging agent being present in the mixture in a proportion of from approximately 5 to approximately 15 percent by weight of the mixture; and b) a synthetic forsterite-rich sand, the synthetic forsterite-rich sand being free-flowing, having a MgO:SiO.sub.2 weight ratio of at least approximately 1.2, a specific gravity of approximately 3 g/cm.sup.3, a void volume of less than approximately 50 percent by volume of the synthetic forsterite-rich sand, and a fusion point of at least approximately 1610.degree. C., wherein i) at least approximately 50 percent by weight of the synthetic forsterite-rich sand is forsterite, and ii) from approximately 3 to approximately 27 percent by weight of the synthetic forsterite-rich sand is maghemite. The compositions and methods provide advantages in that the resulting refractory product have suitable characteristics with respect to size distribution, packing ability, thermal resistance and sintering properties for utilization as ladle sand or for similar refractory uses.

Refractory sand composition

A synthetic forsterite-rich refractory sand composition for use as a taphole nozzle refractory sand for a sliding gate system of a steel ladle, the synthetic forsterite-rich sand composition including a mixture, the mixture including: a) a carbon bridging agent, the carbon bridging agent being present in the mixture in a proportion of from 5 to 15 percent by weight of the mixture; and b) a synthetic forsterite-rich sand, the synthetic forsterite-rich sand being free-flowing, having a MgO:SiO.sub.2 weight ratio of at least 1.2, a specific gravity of approximately 3 g/cm.sup.3, a void volume of less than approximately 50 percent by volume of the synthetic forsterite-rich refractory sand, and a fusion point of at least 1610.degree. C. At least 50 percent by weight of the synthetic forsterite-rich sand is forsterite; and from 8 to 27 percent by weight of the synthetic forsterite-rich sand is maghemite.

Forsterite-rich refractory sand composition

The present invention is concerned with a process for the preparation of sintered calcium aluminates that can generally be used as a protective cover for liquid metals, and particularly steel, and the process comprising the steps of mixing calcium oxide, or its precursor, particles and aluminum dross residue, such as NOVAL.TM.; calcining the resulting mixture; maintaining a calcining temperature of 1200.degree. C. or higher for approximately 5 minutes or more which is sufficient to form a friable sintered product rich in calcium aluminates; and recovering the sintered product after cooling. Optionally, calcium fluoride, or other fluoride can be added to the starting mixture, if it is not already contained in the dross residue.

Process for the preparation of calcium aluminates from aluminum dross

A process for obtaining a synthetic refractory sand for use in steelmaking, said synthetic refractory sand being free-flowing, comprising at least 50% forsterite, having semi-angular and irregularly shaped grains, lenses and flat grains, a specific gravity of approximately 3 g/cm.sup.3, a void volume of less than approximately 50%, a coefficient of thermal expansion of approximately 1.09.times.10.sup.-5 and a fusion point of at least 1610.degree. C. including the steps of: (a) agglomerating a mixture comprising a particulate starting material selected from the group consisting of serpentine-containing asbestos tailings and an enstatite-containing product produced by calcining serpentine-containing asbestos tailings and from 10% to 25%, based on the total weight of mixture, of magnesium oxides or precursors of magnesium oxides with an aqueous binder solution to obtain agglomerates of said mixture; (b) calcining said agglomerates at a temperature of from 1200.degree. C. to 1500.degree. C. for from 1 to 2 hours; (c) recovering said synthetic refractory sand from the calcined agglomerates; and (d) crushing said synthetic refractory sand to a desired mesh size.

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Thetford-Mines, Canada

Yvan Huard