Rare earth modifiers for Portland cement
AssigneeUnion Oil Company of California
InventorEllis M. Gartner
Life of this patent
Estimating the term…
Abstract
Rare earth elements, added to the raw materials mixture fed to a cement kiln, produce cement compositions having increased early compressive strengths. Preparation of such cements requires less grinding of clinkers to achieve equivalent early strengths than similar compositions without the rare earth elements.
Claims34
A particulate raw cement mix comprising bastnasite, a calcium oxide component and a silicon dioxide component.
A particulate portland cement composition comprising a thermally processed material containing between about 0.01 and about 0.20 weight percent of at least one rare earth component, calculated as REO, said rare earth component selected from the group consisting of cerium, europium, samarium, praseodymium, neodymium, gadolinium and compounds thereof, and said composition having a surface area less than about 6000, calculated as Blaine fineness in cm.sup.2 /gram.
A composition prepared by the method comprising the following steps:
- (1) adding a modifying agent to a cement raw mix composition, said modifying agent containing components having one or more rare-earth elements selected from the group consisting of cerium, europium, samarium, praseodymium neodymium and gadolinium in a concentration between about 0.01 and about 0.20 weight percent, calculated as REO, of said product obtained from step (2),
- (2) thermally processing the product obtained from step (1) to produce a solid product, and
- (3) pulverizing said product obtained from step (2) to produce a finished composition having a surface area less than about 6000, calculated as Blaine fineness in cm.sup.2 /gram.
A solid cement composition comprising (1) cement containing a tricalcium silicate component and (2) greater than about 0.01 to less than about 0.20 weight percent of rare earth elements, calculated as REO said rare earth elements selected from the group consisting of cerium, europium, samarium, praseodymium, neodymium, gadolinium and compounds thereof.
Dependencies are inferred from the claim text.