Fertilizer Separation and Recovery (Patent No: 796674)

Inventor: Higgins, John T.

Location: Trail, BC

Comments: N/A

Description: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method for separating solids entrained in a horizontally flowing gas which comprises deflecting said horizontally flowing gas downwardly into a slowly rising column of gas in a separation zone for ejection of the entrained solids into said slowly rising column of, gas, removing said merged gases from said separation zone at a point above said separation zone, and removing said solids from said separation zone at a point below said separation zone.

2. In a method for the production of granules in a rotating drum by spraying a melt onto a bed of nuclei and into a cascading curtain of nuclei and cooling said nuclei by passing a flow of gas through said drum, the improvement which comprises reducing the velocity of the cooling gas and deflecting the cooling gas downwardly into a slowly rising column of, gas in a separation zone and controlling the velocity of rising gas for classification of solids settling out of the cooling gas whereby a primary separation and recovery of said solids is effected.

3. In a method as claimed in claim 2, recycling recovered solids to said bed of nuclei.

4. In a method as claimed in claims 1, 2 or 3, the velocity of said rising column of gas in the separation zone being less than the free-settling velocity of the solids.

5. In a method as claimed in claims 2 or 3, passing the gases from the separation zone to a second stage extraction for recovery of finely divided solids.

6. In a method for the production of granular fertilizer in a rotary drum granulator by spraying a melt of fertilizer compound onto a bed of nuclei and into a cascading curtain of nuclei and passing a current of cooling air through said drum granulator, the improvement which comprises removing entrained solids from said cooling gas, classifying said solids for the recovery of nuclei for recycle to the rotary drum granulator, and passing the exhaust gas to a second stage extraction for recovery of finely divided fertilizer compound values.

7. In a method for the production of strong, hard, coarse granules of a nitrogenous fertilizer compound in a rotary drum granulator containing a granulating zone and a cooling zone by spraying molten nitrogenous fertilizer compound onto a bed of solid particles of said compound and into a curtain of solid particles of said compound in said granulating zone to coat said particles while simultaneously contacting said particles with a current of cooling air passing into said granulating zone from said cooling zone, withdrawing cooling air from said granulating zone, passing said coated particles from said granulating zone to said cooling zone, introducing cooling air into said cooling zone and withdrawing cooled coated particles from said cooling zone, the improvement which comprises reducing the velocity of the cooling air withdrawn from said granulating zone, deflecting said cooling gas downwardly to merge with a slowly rising column of gas in a separation zone, collecting in the lower part of said separation zone solids passing from said granulating zone with said cooling gas, recycling said collected solids to said granulating zone and passing said merged gases from said separation zone to a second stage extraction for recovery of finely divided solids.

8. In a rotary drum granulator having a feed inlet opening, a breech enclosing said feed inlet opening and having a hopper bottom, said hopper bottom having a discharge opening formed therein, and duct means formed in the breech for discharging exhaust gases received from the drum granulator feed inlet opening, baffle means positioned in said breech between said granulator feed inlet opening and said duct means at an oblique angle to the plane of said inlet opening for deflecting the flow of exhaust gas from said inlet opening towards said hopper bottom.

9. In a rotary drum granulator containing a granulating zone and a cooling zone, an air inlet at one end of said granulator opening into said cooling zone, an outlet at said end for discharging solids from said cooling zone, a retaining ring between said cooling zone and said granulating zone defining an opening whereby solids pass from said granulating zone to said cooling zone and air passes from said cooling zone to said granulating zone, a feed inlet at the other end of said granulator opening into said granulating zone, said feed inlet opening constituting means for positioning conduits for solid and liquid feed in said granulating zone and for withdrawing air from said granulating zone, a breech enclosing said feed inlet opening and having a greater cross-sectional area than said opening, said breech having a hopper bottom with a discharge opening formed therein, duct means in the upper part of said breech for discharging exhaust gases passing into said breech from said granulating zone, baffle means in said breech positioned between said feed inlet opening and said duct means at an oblique angle to the plane of said inlet opening for deflecting the flow of exhaust gas from said feed inlet opening towards said hopper bottom, and means communicating with said duct means for drawing air into and through said cooling zone and through said granulating zone and through said breech.