Process for compacting powders
Fluffy powders, such as calcined kaolin clays or air floated clays, can be compacted using a process which comprises applying increasing amounts of pressure to a powder moving through a confinement area. The compacted product has an improved bulk density and improved wet out and slurry incorporation times as compared to the non-compacted starting material feed.
1. A process for compacting a powder, wherein the process comprises the steps of:
A. placing a non-compacted powder in an elongated confinement area having top and bottom belt conveyors which converge toward a product discharge end;
B. moving the powder between the top and bottom belt conveyors in the elongated confinement area;
C. compacting the powder by applying increasing pressure to the moving powder as the powder moves between the top and bottom belt conveyors in the elongated confinement area; and
D. discharging a compacted product having a bulk density which is increased over the bulk density of the non-compacted powder.
2. A process as defined by claim 1 wherein the powder is calcined kaolin clay.
3. A process as defined by claim 1 wherein the powder is an air floated clay.
4. A process as defined by claim 1 wherein the pressure increases to about 450 pounds per square inch.
5. A process as defined by claim 1 wherein the compacted product has a bulk density of at least about 25 pounds per cubic foot.
6. A process as defined by claim 1 wherein the compacted product has a bulk density of at least about 30 pounds per cubic foot.
7. A process as defined by claim 1 wherein the compacted product has a bulk density from about 20 to about 60 pounds per cubic foot.
8. A process as defined by claim 1 wherein the compacted product has an improved wet out time.
9. A process as defined by claim 1 wherein the compacted product has an improved slurry incorporation time.
10. A process as defined by claim 1 wherein the compacted product has a low 325 screen mesh residue.
11. A process as defined by claim 1 wherein the compacted product has good optical properties.
12. A process as defined by claim 1 wherein the compacted product has good rheological properties.