Urea Fertilizer Coating for Blendability and Nutrient Retention

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Solution Overview

Problem

Current methods for incorporating micronutrients into urea-based fertilizers face challenges such as incompatibility with other fertilizers, delayed release, dilution of nutrient content, and segregation of particles, leading to ineffective blending and fertilization.

Innovation Solution

A method involving the application of a liquid concentrated mineral acid with low water content to form a double salt layer on urea-based particles, followed by a solid mineral base in a non-equimolar ratio, creating a grasping layer that allows for the incorporation of micronutrients in the outer shell, enhancing blendability and fertilization efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If micronutrients are incorporated into urea-based particles through conventional blending, then the fertilizer provides balanced nutrition, but chemical incompatibility prevents effective blending

Engineering Contradiction:
ImproveblendabilityVSAvoidchemical compatibility
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces an intermediary coating layer composed of calcium carbonate and magnesium carbonate on the urea particle surface. This coating acts as a physical barrier that prevents direct chemical contact between urea and incompatible fertilizers (such as ammonium nitrate or superphosphates), thereby enabling blending of previously incompatible materials without forming harmful double salts or liquid phases.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite particle structure where urea cores are coated with a composite shell containing calcium carbonate and magnesium carbonate. This composite material approach allows the inner urea to remain chemically pure while the outer shell provides compatibility with other fertilizers, solving the contradiction between maintaining urea's high nitrogen content and achieving blendability.

Inventive Principle:
Principle #40Composite materials

2Quantity of substance

If micronutrients are added to urea-based fertilizers, then plant nutrition is improved, but particle segregation occurs

Engineering Contradiction:
Improvemicronutrient contentVSAvoidparticle uniformity
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by concentrating micronutrients specifically in the outer coating shell rather than uniformly distributing them throughout the entire particle. The core urea remains pure and uniform, while the shell contains the micronutrient enrichment, creating a radial concentration gradient that prevents segregation during handling and application.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the particle into two distinct functional zones: an inner urea core providing nitrogen nutrition and an outer micronutrient-containing shell providing trace element nutrition. This segmentation allows each zone to serve its specific purpose without interfering with the other, preventing the segregation that would occur if micronutrients were mixed throughout the entire particle.

Inventive Principle:
Principle #1Segmentation

3Productivity

If micronutrients are incorporated into urea particles, then fertilization efficiency is improved, but delayed release occurs

Engineering Contradiction:
Improvefertilization efficiencyVSAvoidrelease time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies local quality by placing micronutrients in the outer shell where they are immediately available for plant uptake, while the inner urea core provides sustained nitrogen release. This spatial separation ensures that micronutrients are not delayed in release, as they are already positioned at the particle surface for rapid absorption.

Inventive Principle:
Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method improves the blendability of urea-based fertilizers with other particles and ensures effective distribution of micronutrients, maintaining the chemical form of the solid mineral base for plant uptake, thus overcoming previous drawbacks like delayed release and dilution.

Implementation Method 1

applying a liquid concentrated mineral acid with a water content of at most 25 weight % to urea-based particles having a water content of at most 2 weight %, in order to at least form a double salt layer at the outer surface of the urea-based particles

Methodology Applied
Scientific EffectChemical reaction forming double salt: Chemical Bonding

Implementation Method 2

applying a solid mineral base in powder form to the urea-based particles of step a) in order to react with the grasping layer of the urea-based particles

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

the mineral acid or the solid mineral base are the source of any one of the micronutrients and wherein the liquid concentrated mineral acid and the solid mineral base in powder form are applied in a non-equimolar ratio between 0.1 and 1 mol/mol mineral acid/mineral base

Methodology Applied
Scientific EffectStoichiometric ratio control: Chemical Bonding

Data Source

PatentUS10106470B2Method for incorporating micronutrients in the outer shell of urea-based particles
Publication Date: 2018.10.23 YARA INTERNATIONAL ASA

AI summary

The invention concerns a method for incorporating micronutrients in an outer shell of urea-based particles, characterized in that it comprises the steps of a) applying a liquid concentrated mineral acid with a water content of at most 25 weight % to urea-based particles having a water content of at most 2 weight %, in order to at least form a double salt layer at the outer surface of the urea-based particles such that an acidified particle grasping layer is obtained, and subsequently b) applying a solid mineral base in powder form to the urea-based particles of step a) in order to react with the grasping layer of the urea-based particles; wherein the mineral acid or the solid mineral base are the source of any one of the micronutrients and wherein the liquid concentrated mineral acid and the solid mineral base in powder form are applied in a non-equimolar ratio between 0.1 and 1 mol/mol mineral acid/mineral base. The invention furthermore concerns a particulate urea-based fertilizer, comprising urea-based particles with a water content of at most 2 weight %, comprising micronutrients in an outer shell, the urea-based particles being obtained by a method according to the invention.