Solid Anti-Caking Fertilizer Coatings for Urea–Phosphate Blends

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Solution Overview

Problem

Existing fertilizer blends, particularly those involving urea and phosphate fertilizers like superphosphate or triple superphosphate, suffer from chemical incompatibility issues that lead to undesirable reactions, resulting in a semisolid or muddy mass, and current coatings are costly, require liquid handling, and may cause delayed fertilizer release.

Innovation Solution

A particulate coating composition comprising a solid acidic particulate material, such as single superphosphate or triple superphosphate, and a solid basic particulate material like MgO, ZnO, or CuO, which are mixed to form a stable coating that inhibits chemical reactions between fertilizers, enhancing abrasion resistance and tensile strength without liquid components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If untreated urea is blended with superphosphate or triple superphosphate, then the fertilizer blend provides balanced nutrition, but the fertilizers chemically react to form a semisolid or muddy mass

Engineering Contradiction:

Improvefertilizer blend compatibilityVSAvoidchemical stability

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

A coating layer comprising magnesium oxide particles and calcium carbonate particles is applied to the surface of urea granules. This coating acts as an intermediary barrier that prevents direct chemical contact between urea and phosphate fertilizers, thereby preventing the formation of the semisolid adduct while allowing both fertilizers to coexist in the blend.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a coating is applied to prevent chemical reactions, then chemical compatibility is improved, but production cost increases

Engineering Contradiction:

Improvechemical compatibilityVSAvoidproduction cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The coating uses inexpensive materials - magnesium oxide and calcium carbonate - which are readily available and low-cost. These materials form a simple particulate coating that can be applied directly without complex processing, providing effective chemical compatibility at minimal additional production cost.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the physical state of the coating materials from liquid to solid particulate form. This parameter change eliminates the need for liquid handling equipment, drying steps, and complex coating processes, thereby reducing manufacturing complexity and cost while maintaining coating effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If liquid coating materials are used to form a protective layer, then chemical compatibility is improved, but the process requires liquid handling and drying steps

Engineering Contradiction:

Improvechemical compatibilityVSAvoidprocess complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The liquid coating process is replaced with a dry particulate coating process. Instead of using liquid carriers and evaporation-based application, the invention uses dry particles that can be directly applied and adhered to the urea granule surface through mechanical mixing or fluidization, eliminating the need for liquid handling infrastructure.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 coating composition allows for the production of stable fertilizer blends with improved chemical compatibility, reduced production costs, and enhanced physical properties, enabling the creation of tailored fertilizer blends for specific crop needs.

Implementation Method 1

contacting the fertilizer with at least two reactive ingredients to form a coating of a reaction product, such as reacting a liquid acid with a base

Methodology Applied

Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 2

The coating composition can help reduce or eliminate reactions between coated fertilizers... Blended mixtures of untreated urea granules with SSP or TSP granules have a tendency to chemically react and form a semisolid or muddy mass

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3625195B1Anti-caking fertilizer compositions

Publication Date: 2025.07.02 SABIC AGRI NUTRIENTS CO

Figure 1A~1B
Figure 2A
Figure 2B

AI summary

A particulate fertilizer coating composition or a coated fertilizer containing a solid acidic particulate material and a solid basic particulate material. The coating composition and coated fertilizer are each stable, chemical compatible with other fertilizers, and/or are abrasion resistant.