Granulation of fine powder
AssigneeLos Alamos National Security, LLC
InventorChing-Fong Chen
Life of this patent
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Abstract
A mixture of fine powder including thorium oxide was converted to granulated powder by forming a first-green-body and heat treating the first-green-body at a high temperature to strengthen the first-green-body followed by granulation by crushing or milling the heat-treated first-green-body. The granulated powder was achieved by screening through a combination of sieves to achieve the desired granule size distribution. The granulated powder relies on the thermal bonding to maintain its shape and structure. The granulated powder contains no organic binder and can be stored in a radioactive or other extreme environment. The granulated powder was pressed and sintered to form a dense compact with a higher density and more uniform pore size distribution.
Claims18
A process for granulating fine powder, the process comprising:
- mixing a fine powder having a particle size in a range from 10 nm to 1 mm by dry mixing or wet mixing, the fine powder including cerium oxide and at least one radioactive compound;
- forming a first-green-body from the mixed powder;
- heat treating the first-green-body to a temperature in a range from 100 to 2000 degrees C. to strengthen the structure of the first-green-body;
- forming granulated powder by crushing or milling the heat-treated first-green-body;
- and
- filtering the granulated powder.
A process for forming a compact, the process comprising:
- mixing a fine powder having a particle size in a range from 10 nm to 1mm by dry mixing or wet mixing, the fine powder including cerium oxide and at least one radioactive compound;
- forming a first-green-body from the mixed powder;
- heat treating the first-green-body to a temperature in a range from 100 to 2000 degrees C. to strengthen the structure of the first-green-body;
- forming granulated powder from the first-green-body;
- filtering the granulated powder;
- forming a second-green-body from the granulated powder;
- and
- sintering the second-green body under conditions effective for forming a dense radioactive compact.
Dependencies are inferred from the claim text.