Method of preparing a slow release fertilizer
AssigneeUpm-Kymmene Corporation
InventorsZhiyong Li, Yan Zhang
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Abstract
Provided is a method for preparing slow release fertilizer with a coated surface. Furthermore, a formulation of the coating layer 1 comprises lignin, alkenylsuccinic anhydride, stearic acid, polyethylene glycol (PEG)-2000 and kaolin.
Claims13
A method for preparing a slow-release fertilizer comprising the steps of:
- a) dissolving lignin compounds, alkenylsuccinic anhydride, stearic acid and PEG-2000 in a solvent heated to 50-100° C.;
- b) forming a coating on the surface of urea granules using the solution obtained in step a) and drying;
- c) immersing the coated granules obtained in step b) in alkenylsuccinic anhydride;
- d) adsorbing kaolin onto the surface of the coated granules, wherein the coating materials are 20-80% of the total weight of the coated granules.
A formulation of a coating material comprising 30-70% by weight of the lignin compounds, 10-25% by weight of alkenylsuccinic anhydride, 5-20% by weight of stearic acid, 5-15% by weight of polyethylene glycol PEG2000 and 2-15% by weight of kaolin, wherein all the weight percentages are based on a total weight of the coating material.
Dependencies are inferred from the claim text.