Controlled release formulation for fertilizers
AssigneeReed Lignin, Inc.
InventorWilliam J. Detroit
Life of this patent
Estimating the term…
Abstract
A hydrolyzed lignosulfonate-acrylonitrile graft copolymer matrix providing a slow release solubility to fertilizers. The hydrolysis of the graft copolymer of lignosulfonate and acrylonitrile may be carried out in the presence of an alkali in situ during the fertilizer manufacturing process or in a prehydrolysis step with subsequent use of the hydrolyzed copolymer in the fertilizer manufacturing process to provide a controlled release formulation for various fertilizers.
Claims22
A composition of matter, comprising a fertilizer selected from the group consisting of urea, ammonium nitrate, ammonium phosphate, potassium nitrate, potassium sulfate, potassium chloride and mixtures thereof, and a hydrolyzed lignosulfonate-acrylonitrile copolymer matrix capable of providing slow release solubility for the fertilizer, wherein the copolymer matrix is hydrolyzed with an alkali selected from the group consisting of lithium, potassium, ammonium, calcium and sodium hydroxide, said copolymer matrix having a loading of acrylonitrile to lignosulfonate of about 5% to about 200%, and a loading of said hydrolyzed copolymer to said fertilizer of about 2% to about 20%.
In a fertilizer manufacturing process, a method of providing slow release for the fertilizer wherein said fertilizer is selected from the group consisting of urea, ammonium nitrate, ammonium phosphate, potassium nitrate, potassium sulfate, and potassium chloride comprising the steps of:
- providing a lignosulfonate-acrylonitrile copolymer having a loading of acrylonitrile to lignosulfonate in the copolymer of about 5% to about 200%;
- hydrolyzing the copolymer with an alkali, wherein said alkali is selected from the group consisting of lithium, potassium, ammonium, calcium and sodium hydroxide, and wherein the alkali to copolymer loading is about 10% to about 200%;
- incorporating the hydrolyzed copolymer with a fertilizer selected from the group consisting of urea, ammonium nitrate, ammonium phosphate, potassium nitrate, potassium, sulfate, potassium chloride and mixtures thereof, wherein the hydrolyzed copolymer to fertilizer loading is about 2% to about 20%;
- and
- processing said hydrolyzed copolymer and fertilizer into a solid particulate form.
In a urea fertilizer prill manufacturing process, a method of providing slow release for the urea fertilizer comprising the steps of:
- providing a urea solution containing a lignosulfonate-acrylonitrile copolymer and an alkali, wherein the copolymer matrix is hydrolyzed with an alkali selected from the group consisting of lithium, potassium, ammonium, calcium and sodium hydroxide, and wherein the loading of acrylonitrile to lignosulfonate in the copolymer is about 5% to about 200%, and the loading of alkali to the copolymer is about 10% to about 200%, and the loading of the copolymer to urea is about 2% to about 20%;
- heating the urea solution containing the copolymer and alkali to simultaneously hydrolyze the copolymer and evaporate water therefrom;
- and
- forming prill from the water-evaporated urea and copolymer solution.
In a urea fertilizer prill manufacturing process, a method of providing slow release for the urea fertilizer comprising the steps of:
- providing a lignosulfonate-acrylonitrile copolymer having a loading of acrylonitrile to lignosulfonate in the copolymer of about 5% to about 200%
- hydrolyzing the copolymer with an alkali, wherein the copolymer matrix is hydrolyzed with an alkali selected from the group consisting of lithium, potassium, ammonium, calcium and sodium hydroxide, and wherein the alkali to copolymer loading is about 10% to about 200%;
- incorporating the hydrolyzed copolymer in a urea solution wherein the hydrolyzed copolymer to urea loading is about 2% to about 20%;
- heating the urea solution and hydrolyzed copolymer to evaporate water therefrom;
- and
- forming prill from the water-evaporated urea and copolymer solution.
Dependencies are inferred from the claim text.