Magnesium oxide powder for workable, rapid-setting phosphate-containing cement compositions
AssigneeE. I. Du Pont de Nemours and Company
InventorErnst A. Tomic
Life of this patent
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Abstract
A storable magnesium oxide/phosphate based cement having a delayed set time is provided by heating iron-containing magnesium oxide particles at an elevated temperature to provide magnesium ferrate in a gradient that increases to a maximum at the external particle surface.
Claims7
In a storable cement product containing (a) magnesium oxide particles and (b) an inorganic salt of phosphoric acid, components (a) and (b) being adapted to undergo a reaction in the presence of water and an aggregate to form a hard, cement product, the improvement comprising the use of magnesium oxide particles containing magnesium ferrate in a gradient concentration that increases to a maximum at the external particle surface.
A storable cement product comprised of from about 2 to 27 parts by weight of magnesium oxide particles containing magnesium ferrate in a gradient concentration that increases to a maximum on the external particle surface, from about 5 to 25 parts by weight of inorganic salt of a phosphoric acid and from about 40 to 90 parts by weight of aggregate.
In a rapid-setting composition comprising a mixture of magnesium oxide, a phosphoric acid salt, water and an aggregate, the improvement comprising magnesium oxide particles containing from about 0.1 to 7.5 percent by weight of magnesium ferrate in a gradient concentration that increases to a maximum at the external particle surface.
Dependencies are inferred from the claim text.