Cast bodies, castable compositions, and methods for their production
A low-water-content castable composition produces cast products with an increased modulus of rupture, an increased cold crushing strength, and decreased porosity. The composition employs closed fractions of constituent particles with specified populations and specified gaps in the particle size distribution to produce these properties. The composition is suitable for refractory applications.
1. A castable composition comprising refractory material, wherein the composition comprises:
a) a first grain fraction consisting of particles with diameters less than 100 micrometers;
b) a second grain fraction consisting of particles with diameters less than 100 micrometers; and
c) a plurality of adjacent grain fractions separated by at least one gap in which the ratio of the upper boundary particle diameter to the lower boundary particle diameter is greater than the square root of two, the plurality of grain fractions consisting of particles with diameters greater than 100 micrometers, the plurality of adjacent grain fractions comprising a coarsest grain fraction.
2. A castable composition according to claim 1 , further comprising a third grain fraction consisting of particles with diameters less than 100 micrometers.
3. A castable composition according to claim 2 , further comprising a fourth grain fraction consisting of particles with diameters less than 100 micrometers.
4. A castable composition according to claim 3 , further comprising a fifth grain fraction consisting of particles with diameters less than 100 micrometers.
5. A castable composition according to claim 3 , wherein the first grain fraction, the second grain fraction, the third grain fraction and the fourth grain fraction comprise a material selected from the group consisting of alumina and Secar cement.
6. A castable composition according to claim 1 , wherein the composition consists of more than 4 dry weight percent of particles with diameters less than 100 micrometers.
7. A castable composition according to claim 1 , wherein the composition consists of more than 13 dry weight percent of particles with diameters less than 100 micrometers.
8. A castable composition according to claim 1 , further comprising silica fume.
9. A castable composition according to claim 1 , wherein the coarsest grain fraction comprises at least 50% by weight of the dry composition.
10. A castable composition according to claim 1 , wherein at least one gap contains less than 10% by mass of the dry composition.
11. A castable composition according to claim 1 , wherein at least one gap contains less than 5% by mass of the dry composition.
12. A castable composition according to claim 1 , comprising at least 95 dry weight percent alumina.
13. A castable composition according to claim 1 , wherein the coarsest grain fraction comprises from and including 40% by weight to and including 53% by weight of the composition.
14. A method for producing a cast product, comprising, (a) providing a mold having a cavity which corresponds to the size and shape of the product, (b) filling the cavity with a castable composition according to claim 1 , (c) optionally subjecting the castable composition of the invention to compacting and/or vibration, (d) curing the castable composition to form the cast product, and (e) separating the mold from the cast product.
15. A method for producing a cast product, comprising, (a) providing a mold having a cavity which corresponds to the size and shape of the product, (b) filling the cavity with a castable composition according to claim 1 , (c) subjecting the castable composition of the invention to a compression process, (d) curing the castable composition to form the cast product, and (e) separating the mold from the cast product.