Polysulfide Fertilizer Coatings for Higher Sulfur Loading
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Solution Overview
Problem
Existing fertilizers face challenges with elemental sulfur incorporation due to production constraints, dust risks, and moisture-induced caking, leading to inefficient nutrient delivery and handling issues.
Innovation Solution
Manufacture of polysulfide-enhanced fertilizers using elemental sulfur, an energy source, and a reactive organic compound to form sulfur radicals, which can be incorporated into or coated on granules, providing hydrophobic properties and improved nutrient delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If elemental sulfur is incorporated into fertilizer granules, then sulfur content can be increased, but production constraints limit maximum sulfur incorporation to 15 wt % total sulfur or 7.5 wt % elemental sulfur
Solution Approach 1:
The patent incorporates elemental sulfur into a hydrophobic coating material that forms a composite structure with the fertilizer granule. This composite approach allows higher sulfur content (up to 30 wt % total sulfur or 15 wt % elemental sulfur) to be achieved without violating production constraints, as the sulfur is integrated into the coating matrix rather than simply mixed with the granule material.
Solution Approach 2:
The patent applies a hydrophobic coating as a thin film or shell around the fertilizer granule, embedding elemental sulfur within this coating layer. This flexible shell approach enables higher sulfur incorporation (up to 30 wt % total sulfur) while maintaining granule integrity and avoiding production constraint violations, as the coating can be applied as a continuous layer rather than requiring bulk mixing.
2Quantity of substance
If elemental sulfur is used in coatings, then higher sulfur amounts can be achieved, but elemental sulfur dust is produced due to abrasion during transport and handling which creates an explosion risk
Solution Approach 1:
The patent uses a hydrophobic coating material as an intermediary substance that encapsulates the elemental sulfur. This intermediary coating prevents direct contact between elemental sulfur and the external environment during transport and handling, thereby eliminating dust generation and explosion risks while still allowing high sulfur amounts (up to 30 wt % total sulfur) to be incorporated into the fertilizer product.
Solution Approach 2:
The hydrophobic coating acts as a protective shell or thin film that surrounds and secures the elemental sulfur within the coating matrix. This shell structure prevents sulfur particles from becoming loose and generating dust during abrasion, thereby eliminating explosion risks while maintaining high sulfur content (up to 30 wt % total sulfur) in the fertilizer coating.
3Object-generated harmful factors
If multiple coats of polymers, waxes, and other compounds are applied to alleviate dust risk, then dust risk is reduced, but making and applying these additional coatings can be costly
Solution Approach 1:
The patent employs a hydrophobic coating material that serves multiple functions simultaneously: it provides dust suppression by preventing elemental sulfur dust generation, maintains granule integrity, and enables high sulfur incorporation (up to 30 wt % total sulfur). This multi-functional approach eliminates the need for multiple separate coatings (polymers, waxes, etc.), thereby reducing manufacturing costs while effectively addressing dust risks.
Solution Approach 2:
The patent merges the dust suppression function with the sulfur incorporation function into a single hydrophobic coating application. By combining these two functions into one coating layer rather than applying separate coatings for each purpose, the patent reduces manufacturing complexity and cost while effectively preventing dust generation and enabling high sulfur content (up to 30 wt % total sulfur) in the fertilizer product.
4Quantity of substance
If fertilizer is stored in high humidity conditions, then moisture absorption occurs, but this leads to caking, further degradation of the fertilizer and dust
Solution Approach 1:
The hydrophobic coating acts as a protective shell or thin film that surrounds the fertilizer granule and repels moisture. This hydrophobic barrier prevents water absorption even under high humidity storage conditions, thereby eliminating caking and degradation while allowing the fertilizer to maintain its physical stability and prevent dust generation during storage and handling.
Solution Approach 2:
The patent converts the harmful effect of moisture absorption into a beneficial hydrophobic protective layer. By applying a hydrophobic coating, the fertilizer surface is modified to actively resist moisture rather than absorb it, transforming the storage environment from harmful (high humidity causing caking) to beneficial (moisture-repelling surface that prevents caking and degradation).
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
Polysulfide-enhanced fertilizers offer higher sulfur incorporation rates, reduced moisture absorption, and decreased caking, ensuring efficient nutrient delivery and handling, while being cost-effective and sustainable.
Implementation Method 1
providing inputs of elemental sulfur, an energy source to heat the elemental sulfur to form sulfur radicals
Implementation Method 2
an organic chemical compound with the ability or functionality to react with heated elemental sulfur (radicals) and prevent them from returning to elemental sulfur
Implementation Method 3
the polysulfide can be used with or without additional primary, secondary, and/or micro-nutrients and/or waxes or oils to provide a hydrophobic coating to fertilizer granules
Data Source
AI summary
A polysulfide-enhanced fertilizer product and methods of making same. Polysulfides are manufactured by providing inputs of elemental sulfur, an energy source to heat the elemental sulfur to form sulfur radicals, and an organic chemical compound with the ability or functionality to react with heated elemental sulfur (radicals) and prevent them from returning to elemental sulfur when the mixture is cooled. The polysulfide can be incorporated as a coating on fertilizer granules or within the fertilizer granules. The polysulfide-enhanced granules can be with or without additional primary, secondary, and/or micro-nutrients, biostimulants, urease or nitrification inhibitors pesticides, herbicides, or other compounds providing enhanced efficiency characteristics into a granule.