Patent EA-002577-B1 (EA)
Title: Method for granulating sulfur feedstock and granulated sulfur
Inventor: PHINNEY ROBIN
IPC: C05G5/12
Filed: 1999-04-08
Abstract: 1. A method for granulating a sulfur feedstock into granules, comprising the steps of: providing a sulfur feedstock having about 99.9% particle size of -150 mesh of said 99.9% particle size of -150 mesh about 90% comprising a particle size of -200 mesh; providing a binder material having a moisture content and a surfactant; contacting said sulfur feedstock with said binder to provide a mixture; introducing said mixture on to a pan granulator containing feedstock; maintaining pan moisture conditions where the moisture content on said pan is between about 1.5% by weight to about 11 % by weight; and forming sulfur granules on said pan directly from said sulfur feedstock in the absence of seed or nucleating material. 2. The method as defined in claim 1, further including the step of augmenting said sulfur feedstock with an additive. 3. The method as set forth in claim 2, wherein said additive comprises at least one of copper, boron, encapsulated sulfur oxidizing bacteria, a herbicide, a pesticide or a plant nutrient. 4. The method as set forth in claim 2, wherein said granules are in the size range of -10 mesh to 100 mesh. 5. The method as set forth in claim 1, wherein said binder comprises a material comprising about 30% by weight to about 60% by weight moisture. 6. The method as set forth in claim 4, further including the step of passing said sulfur granules on to a second pan granulator. 7. The method as set forth in claim 5, wherein said feedstock for said second pan includes between about 20% to about 35% sulfur granules in the size range of -10 mesh to about 100 mesh. 8. The method as set forth in claim 1, wherein said moisture content is between about 1.5% by weight and about 10.5% by weight. 9. A method for granulating a sulfur feedstock into granules, comprising the steps of: providing a sulfur feedstock having about 99.9% particle size of -150 mesh of said 99.9% particle size of -150 mesh about 90% comprising a particle size of -200 mesh; providing a binder material having a moisture content and a surfactant; contacting said sulfur feedstock with said binder to provide a mixture; introducing said mixture on to a pan granulator containing feedstock; maintaining pan moisture conditions where the moisture content on said pan is between about 1.5% by weight to about 11 % by weight; and forming sulfur granules having a homogeneous and uniform cross-section on said pan directly from said sulfur feedstock in the absence of seed or nucleating material. treating said granules with a dust suppressant. 10. The method as set forth in claim 9, further including the step of augmenting said sulfur feedstock with an additive. 11. The method as set forth in claim 10, wherein said additive comprises at least one of copper, boron, encapsulated sulfur oxidizing bacteria, a herbicide, a pesticide or a plant nutrient. 12. The method as set forth in claim 10, wherein said granules are in the size range of -10 mesh to 100 mesh. 13. The method as set forth in claim 9, wherein said surfactant comprises a sulphonic surfactant. 14. The method as set forth in claim 9, wherein said dust suppressant comprises an oil. 15. The method as set forth in claim 9, further including the step of adding a limited solubility coating to said granules for effecting a time release of said sulfur. 16. The method as set forth in claim 15, wherein said coating is added to said feedstock at intervals during accretion of said granules. 17. The method as set forth in claim 9, further including the step of passing said sulfur granules on to a second pan granulator. 18. The method as set forth in claim 16, wherein feedstock for said second pan includes between about 20% to about 35% sulfur granules in the size range of 10 mesh to about 100 mesh. 19. A sulfur granule formed as set forth in claim 1. 20. The  sulfur granule having a homogeneous and uniform cross section and an additive selected from the group comprising a plant nutrient, a plant growth regulator, bacteria and minerals. 21. The sulfur granule as set forth in claim 18, wherein said granule comprises a fumigant in the size distribution of 10 mesh. 22. A method for granulating a sulfur feedstock into granules, comprising the steps of: providing a sulfur feedstock having about 99.9% particle size of -150 mesh of said 99.9% particle size of -150 mesh about 90% comprising a particle size of -200 mesh; providing a binder material having a moisture content and a surfactant; contacting said sulfur feedstock with said binder to provide a mixture; forming a prewetted mixture of said binding material, said feedstock, moisture and said surfactant, said mixture has moisture content between 4% by weight and 8% by weight; introducing said mixture on to a pan granulator containing feedstock; maintaining pan moisture conditions where the moisture content on said pan is between about 1.5% by weight to about 11% by weight; forming sulfur granules in a size distribution of +8 mesh to -4 with output of at least 95% on said pan directly from contacting said prewetted mixture with said sulfur feedstock in the absence of seed. 23. A method for granulating a sulfur feedstock into granules, comprising the steps of: providing a sulfur feedstock having about 99.9% particle size of -150 mesh of said 99.9% particle size of -150 mesh about 90% comprising a particle size of -200 mesh; providing a binder material having a moisture content and a surfactant; contacting said sulfur feedstock with said binder to provide a mixture; forming a prewetted mixture of said binding material, said feedstock, moisture and said surfactant, said mixture has moisture content between 4% by weight and 8% by weight; introducing said mixture on to a pan granulator containing feedstock; maintaining pan moisture conditions where the moisture content on said pan is between about 1.5% by weight to about 11% by weight; forming sulfur granules in a size distribution of +8 mesh to -4 with output of at least 95% on said pan directly from contacting said prewetted mixture with said sulfur feedstock in the absence of seed and treating said granules with a dust suppressant.