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US 5,211,985 AGranted
Multi-stage process for continuous coating of fertilizer particles
AssigneeICI Canada Inc.
InventorsArthur R. Shirley, Jr., Keith D. Cochran, Terence B. Lynch, Russell I. Derrah, Sayeeda J. Quadir, Zdzislaw M. Tulimowski
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Abstract
An apparatus and method for continuously producing polymer coated particles, and in particular, a polymer coated fertilizer, wherein the coating material used is, for example, an aqueous film forming latex. The coating process is conducted with a plurality of fluidized beds, connected in series, under conditions such that, preferably, the relative humidity of the air in the initial coating zones is maintained below the critical relative humidity of the particle to be coated.
Claims38
A process for the continuous coating of water-sensitive fertilizer substrate particles comprising:
- providing a plurality of fluidized bed zones for maintaining fertilizer substrate particles in a fluidized condition by means of a fluidizing gas, said fluidized bed zones including at least first and second fluidized bed coating zones;
- providing spraying means in said first and second fluidized bed coating zones for applying a coating material onto particles in said fluidized bed coating zones;
- continuously feeding substrate particles into said first fluidized bed coating zone and applying coating material to the particles while fluidized therein;
- transferring said particles from said first fluidized bed coating zone to said second fluidized bed coating zone and spraying coating material onto the particles while fluidized therein;
- continuously removing coated substrate particles from the second fluidized bed coating zone;
- and
- maintaining the relative humidity of the fluidizing gas in at least the first of said fluidized bed coating zones below the critical relative humidity of said particles.
4 more elements
A process for the continuous coating of fertilizer substrate particles comprising:
- providing a plurality of fluidized bed zones for maintaining fertilizer substrate particles in a fluidized condition by means of a fluidizing gas, said fluidized bed zones including at least first and second fluidized bed coating zones;
- providing spraying means in said first and second fluidized bed coating zones for applying a coating material onto particles in said fluidized bed coating zones;
- continuously feeding substrate particles into said first fluidized bed coating zone and spraying coating material onto the particles while fluidized therein;
- transferring said particles from said first fluidized bed coating zones to said second fluidized bed coating zone and spraying coating material onto the particles while fluidized therein, said particles being transferred by a transfer means which comprises a conduit having an upper opening in the upper portion of the first fluidized bed coating zone and a lower opening in the lower portion of the second fluidized bed coating zone so as to cause particles from said first fluidized bed coating zone to enter said conduit at said upper opening, and to exit said conduit at said lower opening into said second fluidized bed coating zone;
- and
- continuously removing coated substrate particles from the second fluidized bed coating zone.
3 more elements
A process for the continuous coating of fertilizer substrate particles comprising:
- providing a plurality of fluidized bed zones for maintaining fertilizer substrate particles in a fluidized condition by means of a fluidizing gas, said fluidized bed zones including at least first and second fluidized bed coating zones;
- providing spraying means in said first and second fluidized bed coating zones for applying a coating material onto particles in said fluidized bed coating zones;
- continuously feeding substrate particles into said first fluidized bed coating zone and spraying coating material onto said particles while fluidized therein;
- maintaining the relative humidity in the first fluidized bed coating zone below the critical relative humidity of the fertilizer substrate particles;
- transferring said particles from said first fluidized bed coating zone to said second fluidized bed coating zone and spraying coating material onto the particles while fluidized therein;
- and
- continuously removing coated substrate particles from the second fluidized bed coating zone;
- wherein said coating material sprayed onto the particles in said second fluidized bed coating zone is a material including the same or a different fertilizer as the substrate particles.
5 more elements
A process for the continuous coating of water sensitive fertilizer substrate particles comprising:
- providing a plurality of fluidized bed zones for maintaining water sensitive fertilizer substrate particles in a fluidized condition by a pressurized stream of gas;
- providing means in at least two of said fluidized bed zones for applying a coating material onto particles in said fluidized bed zones, to provide at least first and second fluidized bed coating zones;
- maintaining the relative humidity in the first fluidized bed coating zone below the critical relative humidity of the fertilizer substrate particles;
- continuously feeding substrate particles into said first fluidized bed coating zone and coating the particles therein;
- transferring said particles from said first fluidized bed coating zone to said second fluidized bed coating zone and coating said substrate particles in said second zone;
- and
- continuously removing coated substrate particles from the second fluidized bed coating zone.
4 more elements
Dependencies are inferred from the claim text.