Freezing inorganic particulate slurries

Claim 2

A process of freezing an inorganic particulate aqueous slurry or suspension containing a freeze-sensitive colloidal ceramic sol which comprises supercooling the slurry in a freezing media and then freezing the slurry.

Claim 3

A process according to claim 1 in which the ceramic sol is a silica sol.

Claim 4

A process according to claim 1 in which the particulate slurry is a ceramic slurry.

Claim 5

A process according to claim 3 in which the ceramic is alumina, magnesia, zirconia, silica, zircon, mullite, uranium oxide, or clay.

Claim 6

A process according to claim 1, 2, 3 or 4 in which the particulate slurry contains lithium ions in a sufficient amount to inhibit ice crystal growth.

Claim 7

A process according to claims 1, 2, 3 or 4 in which the freezing media is a hydrophobic liquid.

Claim 8

A process according to claims 1, 2 3 or 4 in which the freezing media is hydrophobic and the particulate slurry is completely surrounded by the hydrophobic liquid.

Claim 9

A process for freezing an inorganic particulate aqueous slurry or suspension containing a freeze-sensitive ceramic colloidal sol which comprises treating a mold with a hydrophobic liquid to completely cover the working surface of the mold with the hydrophobic liquid, inserting the particulate slurry or suspension into the mold and in contact with the working surface thereof while the working suface is still wet with the hydrophobic liquid, reducing the temperature of the slurry to a sufficient degree to supercool the slurry, and thereafter freezing the supercooled slurry.

Claim 10

A process for freezing an inorganic particulate aqueous slurry or suspension containing a freeze-sensitive ceramic colloidal sol which comprises treating a mold with a hydrophobic liquid to completely cover the working surface of the mold with the hydrophobic liquid, inserting the particulate slurry or suspension into the mold and in contact with the working surface thereof while the working suface is still wet with the hydrophobic liquid, reducing the temperature of the slurry to a sufficient degree to supercool the slurry, and thereafter freezing the supercooled slurry.

Claim 11

A process according to claim 8 in which the slurry or suspension contains lithium ions in an amount sufficient to inhibit large ice crystal growth.

Claim 12

A process according to claim 8 in which the temperature of the slurry is reduced in a freezing media and the freezing media is a hydrophobic liquid freezing media.

Claim 13

A process according to claim 10 in which the hydrophobic liquid and the hydrophobic liquid freezing media are the same.

Claim 14

A process according to claim 11 in which the hydrophobic liquids are freon or perchloroethylene.

Claim 15

A process for freezing an aqueous refractory particle slurry containing a freeze-sensitive colloidal ceramic sol which comprises treating a mold with a hydrophobic liquid to completely cover the working surface of the mold with the hydrophobic liquid, inserting the ceramic slurry into the mold in contact with the working surface while the working surface is still wet with the hydrophobic liquid, reducing the temperature of the slurry while the slurry is in contact with said working surface to a sufficient degree to supercool the slurry, and thereafter freezing the slurry.

Claim 16

A process for freezing an aqueous refractory particle slurry containing a freeze-sensitive colloidal ceramic sol which comprises treating a mold with a hydrophobic liquid to completely cover the working surface of the mold with the hydrophobic liquid, inserting the ceramic slurry into the mold in contact with the working surface while the working surface is still wet with the hydrophobic liquid, reducing the temperature of the slurry while the slurry is in contact with said working surface to a sufficient degree to supercool the slurry, and thereafter freezing the slurry.

Claim 17

A process according to claim 13 in which the mold contains the slurry on all sides except the top side, a hydrophobic liquid is placed on the slurry exposed at the top side in a sufficient amount to cover the slurry, a top closure placed on the mold top, and the slurry then supercooled and then frozen.

Claim 18

A process according to claim 13 in which the frozen slurry is removed from the mold, thawed, dried and fired.

Claim 19

A process according to claim 13 in which the aqueous slurry contains lithium ions in a sufficient amount to inhibit the growth of ice crystals.

Claim 20

A process according to claim 13 in which the temperature of the slurry is reduced in a freezing media and the freezing media is a hydrophobic liquid freezing media.

Claim 21

A process according to claim 17 in which the hydrophobic liquid and the hydrophobic liquid freezing media are the same.

Claim 22

A process according to claim 18 in which the hydrophobic liquids are freon or perchloroethylene.

Claim 23

A process of freezing an inorganic particulate slurry or suspension containing a freeze sensitive colloidial ceramic sol which comprises regulating or adjusting the relative zeta potentials of the particular particles and the sol particles to cause the sol particles to precipitate onto the surface of the particulate particles during the mixing of the particles.

Claim 24

A process of freezing an inorganic particulate slurry or suspension containing a freeze sensitive colloidial ceramic sol which comprises regulating or adjusting the relative zeta potentials of the particular particles and the sol particles to cause the sol particles to precipitate onto the surface of the particulate particles during the mixing of the particles.

Claim 25

A process according to claim 20 in which the inorganic particulate slurry contains magnesia or zirconia particles.

Claim 26

A process of freezing an inorganic particulate slurry or suspension containing a freeze sensitive ceramic sol which comprises freezing the slurry or suspension in the presence of lithium ions contained in the slurry or suspension in an amount sufficient to inhibit ice crystal growth.

Claim 27

A process of freezing an inorganic particulate slurry or suspension containing a freeze sensitive ceramic sol which comprises freezing the slurry or suspension in the presence of lithium ions contained in the slurry or suspension in an amount sufficient to inhibit ice crystal growth.

Claim 28

A process according to claim 22 in which the slurry or suspension is supercooled before it is frozen.