Nitride-based controlled-release fertilizers and process for making same

Patent metadata

Field	Value
Publication number	US-10005699-B2
Application number	US-201615222632-A
Country	US
Kind code	B2
Filing date	Jul 28, 2016
Priority date	Jul 28, 2016
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A controlled-release solid nitride fertilizer from fly ash and a method for making are described. The fertilizer includes a nitrogen source including at least one solid nitride combined with at least one precipitation-inhibiting agent and with at least one moisture-retention agent, all compressed together to form a porous release structure that in contact with water releases ammonium ions as a nitrogen nutrient at a substantially uniform release rate over a selected release period and thereby maximizes nitrogen-use efficiency by plants.

First claim

What is claimed is:

1. A controlled-release fertilizer composition comprising: a homogeneous blend having at least one solid nitride selected from the group consisting of AlN, Ca3N2, Ca3AlN3, CaAlSiN3, and combinations thereof;
at least one precipitation-inhibiting agent selected from the group consisting of Ca2P2O7, Ca3(PO4)2, CaH4(PO4)2, K2HPO4, KH2PO4, K4P2O7, KHCO3, Na4P2O7, and combinations thereof;
at least one moisture retention agent selected from the group consisting of starch, cellulose, or combinations thereof; and
at least one hydrolysis catalyst selected from the group consisting of CaO, K2O, Na2O, CaCO3, Ca(OH)2, and combinations thereof;
wherein the solid nitride, the precipitation-inhibiting reagent, the hydrolysis catalyst and the moisture-retention agent are combined in a granule with a porous structure that releases ammonium ions at a substantially uniform release rate over a selected period of time.

2. The composition of claim 1 , further comprising at least one aluminum-chelating agent selected from the group consisting of potassium salts of citrate, acetate, pyrophosphate, acids thereof, and combinations thereof.

3. A controlled-release fertilizer composition, comprising:
a homogeneous blend having a solid aluminum nitride (AlN) that makes up at least fifty percent by weight of the homogeneous blend, a monopotassium dihydrogen phosphate (KH2PO4) precipitation agent that makes up about twenty percent by weight of the homogeneous blend, a moisture-retention agent that makes up about five percent by weight of the homogenous blend, with the homogenous blend of materials being arranged in a porous structure; wherein
the at least one moisture retention agent is selected from the group consisting of starch, cellulose, or combinations thereof.

4. The composition of claim 1 wherein the at least one precipitation-inhibiting agent is dipotassium monohydrogen phosphate (K 2 HPO 4 ).

5. The composition of claim 3 , wherein nitrogen is released at a rate of from 0.5% to 1.5% of a total initial nitrogen content per day when reacted in water at a temperature of 25° C.

6. A process for making a solid nitride-containing fertilizer, comprising the step of compressing a homogeneous blend comprising at least one solid nitride comprising aluminum (Al), calcium (Ca), or Al and Ca, at least one moisture-retention agent, and at least one precipitation-inhibiting agent together by extruding a wet and congealed form of the homogeneous blend through an extrusion device then compressing using a compression pressure of at least about 30 MPa.

Assignees

• Battelle Memorial Institute

Inventors

• Amonette James E
• Matyas Josef

Classifications

• C05C11/00

  Other nitrogenous fertilisers · CPC title

• C05B7/00 Primary

  Fertilisers based essentially on alkali or ammonium orthophosphates (C05B11/00 takes precedence) · CPC title

• C05G3/40 Primary

  for affecting fertiliser dosage or release rate; for affecting solubility · CPC title

• C05G3/0094 Primary

  Chemistry & Metallurgy · mapped topic