Slow-release (GSSP) fertilizer
AssigneeUniversity of South Florida
InventorsJay W. Palmer, Heidi Kay
Life of this patent
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Abstract
Several compositions of matter have been discovered that can be used in the manufacture of slow-release fertilizers that contain all of the essential elements needed by plants and humans. Slow-release fertilizers manufactured with these formulations can be used on mineral stressed soils to increase the quality and production of food crops grown on them. Additives, including phosphogypsum, silica sand, natural gypsum, clay, and coal dust, facilitate the timing of the release of the essential elements into the soil.
Claims21
A slow-release fertilizer comprising:
- a mixture comprising monocalcium phosphate, dicalcium phosphate, gypsum, and magnesium sulfate;
- dolomitic phosphatic clay slime comprising micro and trace essential elements;
- urea;
- and
- potassium chloride;
- and
- an additive;
- wherein the mixture is prepared by mixing a phosphate ore with sulfuric acid and water, and wherein the phosphate ore of the mixture is a dolomitic phosphate ore;
- wherein the dolomitic phosphate ore comprises about 2% MgO;
- and
- wherein the additive is phosphogypsum.
A method for preparing a slow-release fertilizer comprising:
- a) preparing a first mixture by mixing a phosphate ore with sulfuric acid and water to form monocalcium phosphate, gypsum, magnesium sulfate, and residual phosphate ore;
- b) adding to the first mixture micro and trace essential elements and dolomitic phosphatic clay slime to yield a second mixture;
- c) heating the second mixture to yield a third mixture comprising dicalcium phosphate and residual phosphoric acid;
- d) adding phosphate to the third mixture to neutralize the residual phosphoric acid to yield a fourth mixture;
- e) adding urea and potassium chloride to the fourth mixture to form a fertilizer mixture;
- f) drying the fertilizer mixture;
- and
- g) incorporating an additive selected from the group consisting of phosphogypsum, silica sand, natural gypsum, clay, coal dust, and a combination of any of the foregoing into the dried fertilizer mixture.
Dependencies are inferred from the claim text.