US3903333A — Production of slow release nitrogen fertilizers b…

Claim 1

Independent Claim 358 words

IN AN IMPROVED PROCESS FOR APPLYING A PRECISELY UNIFORM SOLID COATING OF FLUID SULFUR MATERIAL SPRAYED ONTO THE SURFACE OF SOLID UREA GRANULES IN A ROTARY COATING DRUM, THE AXIS OF WHICH IS IN A GENERALLY HORIZONTAL ATTITUDE AND HAVING ITS LENGTH EQUAL TO FROM ABOUT 1 1/2 TO ABOUT 10 TIMES ITS DIAMETER WHICH COMPRISES: PREPARING THE SURFACE OF SAID SOLID UREA GRANULES PRIOR TO THEIR COATING WITH SAID FLUID SULFUR SPRAY THEREONTO TO EFFECT SMOOTH, ROUND FRANULAR FROM THEREOF, LOADING SAID PREPARED GRANULES INTO SAID DRUM TO ABOUT 3 TO ABOUT 10 PERCENT OF ITS FULL LOADING CAPACITY, HEATING SAID PREPARED GRANULES IN SAID ROTARY COATING DRUM TO MAINTAIN THE TEMPERATURE THEREOF IN THE RANGE ABOUT 170* TO ABOUT 203.9*F, ROATING SAID LOADED DRUM AT A SPEED FROM ABOUT 30 TO ABOUT 80 PERCENT OF SAID DRUM''S CRITICAL SPEED, SAID CRITICAL SPEED (RPM)=76.5/SQUARE ROOT D WHERE D REPRESENTS THE DIAMETER OF THE DRUM IN FEET TO FORM A ROLLING BED OF SAID GRANULES THERIN, APPLYING SAID FLUID SULFUR COATING MATERIAL ONTO SAID ROLLING BED OF SAI GRANULES THROUGH A PLURALITY OF SPRAY APERTURES OF THE AIR-ATOMIZING TYPE AT PREDETERMINED RATES IN A GENERALLY VERTICAL DOWNWARD DIRECTION ONTO THE PORTION OF SAID GRANULES IN SAID BED TO WHICH IS IMPARTED A CASCADING MOTION BY SAID ROTATION OF SAID DRUM, AND THEREAFTER COOLING AND COLLECTING AS PRODUCT THE RESULTING SULFUR COATED SOLID GRANULES AS PRECISELY UNIFORM SULUFR COATED UREA, THE IMPROVEMENT IN COMBINATION THEREWEWITH FOR ENSURING THAT EACH GRANULE TO BE COATED IS COVERED BY A PLURALITY OF SWQUENTIALLY APPLIED STREAMS OF SAID FUID SULFUR MATERIAL, THEREBY FORMING THEREON A MULTITUDE OF RELATIVELY THINLY APPLIED CONCENTRICALLY FORMED LAYER OF COATING BY A PROCESS WHICH COMPRISED THE ADDITIONAL STEP OF PREDETERMINING THE DESIRED FLOW RATE FROM EACH OF SAID SPRAY APERTURES FOR A FIXED WORKING PRESSURE ON SAID FLUID SULFUR COATING MATERIAL FED THERETO BY MEANS OF RESTRICTING THE FLOW OF SAID FLUID SULFUR COATING MATERIAL TO EACH OF SAID SPRAY APERTURES BY PROCIDING ORIFICES IN THE FLUID SYSTEM IMMEDIATLY UPSTREAM OF EACH OF SAID SPRAY APERTURES, SAID ORIFICE DIAMETER RANGING BETWEEN 0.015 AND ABOUT 0.050 INCH IN DIAMETER.

Claim 2

Dependent Claim 358 words

IN AN IMPROVED PROCESS FOR APPLYING A PRECISELY UNIFORM SOLID COATING OF FLUID SULFUR MATERIAL SPRAYED ONTO THE SURFACE OF SOLID UREA GRANULES IN A ROTARY COATING DRUM, THE AXIS OF WHICH IS IN A GENERALLY HORIZONTAL ATTITUDE AND HAVING ITS LENGTH EQUAL TO FROM ABOUT 1 1/2 TO ABOUT 10 TIMES ITS DIAMETER WHICH COMPRISES: PREPARING THE SURFACE OF SAID SOLID UREA GRANULES PRIOR TO THEIR COATING WITH SAID FLUID SULFUR SPRAY THEREONTO TO EFFECT SMOOTH, ROUND FRANULAR FROM THEREOF, LOADING SAID PREPARED GRANULES INTO SAID DRUM TO ABOUT 3 TO ABOUT 10 PERCENT OF ITS FULL LOADING CAPACITY, HEATING SAID PREPARED GRANULES IN SAID ROTARY COATING DRUM TO MAINTAIN THE TEMPERATURE THEREOF IN THE RANGE ABOUT 170* TO ABOUT 203.9*F, ROATING SAID LOADED DRUM AT A SPEED FROM ABOUT 30 TO ABOUT 80 PERCENT OF SAID DRUM''S CRITICAL SPEED, SAID CRITICAL SPEED (RPM)=76.5/SQUARE ROOT D WHERE D REPRESENTS THE DIAMETER OF THE DRUM IN FEET TO FORM A ROLLING BED OF SAID GRANULES THERIN, APPLYING SAID FLUID SULFUR COATING MATERIAL ONTO SAID ROLLING BED OF SAI GRANULES THROUGH A PLURALITY OF SPRAY APERTURES OF THE AIR-ATOMIZING TYPE AT PREDETERMINED RATES IN A GENERALLY VERTICAL DOWNWARD DIRECTION ONTO THE PORTION OF SAID GRANULES IN SAID BED TO WHICH IS IMPARTED A CASCADING MOTION BY SAID ROTATION OF SAID DRUM, AND THEREAFTER COOLING AND COLLECTING AS PRODUCT THE RESULTING SULFUR COATED SOLID GRANULES AS PRECISELY UNIFORM SULUFR COATED UREA, THE IMPROVEMENT IN COMBINATION THEREWEWITH FOR ENSURING THAT EACH GRANULE TO BE COATED IS COVERED BY A PLURALITY OF SWQUENTIALLY APPLIED STREAMS OF SAID FUID SULFUR MATERIAL, THEREBY FORMING THEREON A MULTITUDE OF RELATIVELY THINLY APPLIED CONCENTRICALLY FORMED LAYER OF COATING BY A PROCESS WHICH COMPRISED THE ADDITIONAL STEP OF PREDETERMINING THE DESIRED FLOW RATE FROM EACH OF SAID SPRAY APERTURES FOR A FIXED WORKING PRESSURE ON SAID FLUID SULFUR COATING MATERIAL FED THERETO BY MEANS OF RESTRICTING THE FLOW OF SAID FLUID SULFUR COATING MATERIAL TO EACH OF SAID SPRAY APERTURES BY PROCIDING ORIFICES IN THE FLUID SYSTEM IMMEDIATLY UPSTREAM OF EACH OF SAID SPRAY APERTURES, SAID ORIFICE DIAMETER RANGING BETWEEN 0.015 AND ABOUT 0.050 INCH IN DIAMETER.

Claim 3

Dependent Claim 243 words

The process of claim 1 wherein said step of preparing the surface of said solid urea granules comprises rotating a preheating drum at a speed of about 15 to about 75 percent of said preheating drum''s critical speed; heating the inner shell and surface of said preheating rotary drum; introducing said substrate material particles into said preheating rotating drum in amounts ranging from 5 to 40 percent of its full load capacity to provide contact therewith said substrate material whereby a portion of the heat energy from said hot inner shell is subsequently imparted to substantially only thE surface of said substrate material to cause superficial fusion of said substrate material particles to smooth same by rolling contact between said substrate material particles so heated and adjacent substrate particles; adjusting the heat input to said preheating drum to provide that the heat transferred from the hot shell of said preheating drum to the urea substrate material is represented by the following equation: q Q(U. C. T.) where q varies in the range from about 0.05 to about 0.35 Btu per square foot of contact area and represents the heat transferred per unit of shell area from the preheater to granules in contact with it per contact; Q is the heat-transfer rate between the drum and granules in contact with it; and (U. C. T.) is the uninterrupted contact time of the granules with the preheater, and where U.C.T. is represented by the equation:

Claim 4

Dependent Claim 24 words

maintaining the temperature of the fluid sulfur material during application onto said substrate material in the temperature range of about 250*F to about 318*F;

Claim 5

Dependent Claim 24 words

maintaining the temperature of the fluid sulfur material during application onto said substrate material in the temperature range of about 250*F to about 318*F;

Claim 6

Dependent Claim 23 words

maintaining the gage pressure in said spray apertures of the hydraulic pressure-atomizing type at greater than about 300 pounds per square inch; and

Claim 7

Dependent Claim 23 words

maintaining the gage pressure in said spray apertures of the hydraulic pressure-atomizing type at greater than about 300 pounds per square inch; and

Claim 8

Dependent Claim 15 words

The process of claim 2 wherein said heat source is of the radiant energy type.

Claim 9

Dependent Claim 128 words

The process of claim 2 wherein said rolling bed in said coating drum he heated to maintain its temperature below 203.9*F, wherein the fluid coating sulfur material is heated and sprayed below 318*F and wherein the bed material in said coating drum is heated to a temperature sufficiently close to 203.9*F to assure a mosaic structure of the applied sulfur coating consisting of orthrhombic crystals in an amorphous matrix, thereby producing a slow-release fertilizer of less than 30 percent by weight dissolution of water-soluble materials in 100*F water in 7 days with a coating of less than 40 percent by weight sulfur without the addition of any other substances except sulfur to the surface of the substrate material, the sulfur-coated material, or to the sulfur to be sprayed.

Claim 10

Dependent Claim 93 words

withdrawing from the discharge end of said rotary coating drum the resulting product at a temperature in the range of about 110* to about 200*F; said process characterized by the fact that produced therefrom is a slow-release fertilizer of less than about 50 percent by weight dissolution of water-soluble materials in 100*F water in 7 days with a coating of less than 40 percent by weight sulfur without the addition of any other substance except sulfur to the surface of the substrate material, the sulfur-coated material, or to the sulfur to be sprayed.

Claim 11

Dependent Claim 93 words

withdrawing from the discharge end of said rotary coating drum the resulting product at a temperature in the range of about 110* to about 200*F; said process characterized by the fact that produced therefrom is a slow-release fertilizer of less than about 50 percent by weight dissolution of water-soluble materials in 100*F water in 7 days with a coating of less than 40 percent by weight sulfur without the addition of any other substance except sulfur to the surface of the substrate material, the sulfur-coated material, or to the sulfur to be sprayed.

Claim 12

Dependent Claim 29 words

The process of claim 4 in which the temperature of the molten sulfur fed to said coating drum is maintained in the range from about 275* to about 318*F.

Claim 13

Dependent Claim 53 words

The process of claim 4 wherein said temperature of the rolling bed is above 203.9*F, but sufficiently close to said temperature to assure said mosaic structure of the sulfur coating by subsequently rapid cooling thereof to lower the temperature of the resulting coated urea to a range from about 60* to about 150*F.

Claim 14

Dependent Claim 127 words

The process of claim 1 wherein said rolling bed is heated in said rotating coating drum to maintain its temperature below 203.9*F, wherein said fluid coating sulfur material is heated to maintain its temperature below 318*F, and wherein said bed material is heated to a temperature sufficiently close to 203.9*F to assure a mosaic structure of the applied sulfur coating consisting of orthrhombic crystals in an amorphous matrix, thereby producing a slow-release fertilizer of less than 30 percent by weight dissolution of water-soluble materials in 100*F water in 7 days with a coating of less than 40 percent by weight sulfur without the addition of any other substance except sulfur to the surface of the substrate material, the sulfur-coated material, or to the sulfur to be sprayed.

Claim 15

Dependent Claim 143 words

In an improved process for applying a precisely uniform solid coating of fluid sulfur material sprayed onto the surface of solid urea granules in a rotary coating drum, the axis of which is in a generally horizontal attitude and having its length equal to from about 1 1/2 to about 10 times its diameter which comprises: preparing the surface of said solid urea granules prior to their coating with said fluid sulfur sprayed thereonto to effect smooth, round granular form thereof; loading said prepared granules into said drum to about 3 to about 20 percent of its full loading capacity; heating and/or cooling said prepared granules in said rotary coating drum to maintain the temperature thereof in a predetermined temperature range; rotating said loaded drum at a speed from about 20 to about 80 percent of said drum''s critical speed, said critical speed

Claim 16

Dependent Claim 143 words

In an improved process for applying a precisely uniform solid coating of fluid sulfur material sprayed onto the surface of solid urea granules in a rotary coating drum, the axis of which is in a generally horizontal attitude and having its length equal to from about 1 1/2 to about 10 times its diameter which comprises: preparing the surface of said solid urea granules prior to their coating with said fluid sulfur sprayed thereonto to effect smooth, round granular form thereof; loading said prepared granules into said drum to about 3 to about 20 percent of its full loading capacity; heating and/or cooling said prepared granules in said rotary coating drum to maintain the temperature thereof in a predetermined temperature range; rotating said loaded drum at a speed from about 20 to about 80 percent of said drum''s critical speed, said critical speed

Claim 17

Dependent Claim 29 words

The process of claim 8 wherein said withdrawn material discharged in excess of 180*F is quick cooled to about 130*F in a period of less than about 5 minutes.

Claim 18

Dependent Claim 86 words

The process of claim 8 wherein said substrate temperature ranges from about 130* to about 170*F, the temperature of said fluid sulfur material is in the range of about 275* to about 318*F; the pressure in the spray apertures of the hydraulic pressure-atomizing type is maintained in the range from about 500 to about 3000 pounds per square inch, and the temperature of the product withdrawn from the discharge end of said rotary coating drum is maintained in the range of about 155* to about 190*F.

Claim 19

Dependent Claim 86 words

The process of claim 10 wherein said substrate temperature ranges from about 130* to about 160*F; the temperature of said fluid sulfur material is in the range of about 300* to about 318*F; the pressure in the spray apertures of the hydraulic pressure-atomizing type is maintained in the range from about 750 to about 1500 pounds per square inch; and the temperature of the product withdrawn from the discharge end of said rotary coating drum is maintained in the range of about 155* to about 180*F.

Claim 20

Dependent Claim 29 words

The process of claim 10 wherein said withDrawn material discharged in excess of 180*F is quick cooled to about 130*F in a period of less than about 5 minutes.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1978-09-01	1979-03-03	1979-09-02	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1982-09-01	1983-03-03	1983-09-02	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1986-09-01	1987-03-03	1987-09-02	$7700.00	Window Closed / Lapsed

Production of slow release nitrogen fertilizers by improved method of coating urea with sulfur

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