Fertiliser pH Control for Zinc Oxide Solubility

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Solution Overview

Problem

Existing micronutrient-enriched fertilizers face challenges such as low solubility and uneven distribution of micronutrients in soil, leading to reduced availability for plants, and micronutrient loss through abrasion.

Innovation Solution

A process for preparing micronutrient-enriched phosphate-based fertilizers involves controlling the pH of an aqueous mixture comprising phosphoric acid, ammonia, and elemental sulfur to maintain a range of 3.5 to 3.9, allowing for the incorporation of zinc oxide as a micronutrient source, which enhances solubility and availability in the fertilizers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If micronutrient is incorporated into bulk fertiliser, then micronutrient can be provided to plants, but solubility of micronutrient becomes low and availability to plants is reduced

Engineering Contradiction:
Improvemicronutrient concentrationVSAvoidmicronutrient solubility
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies parameter changes by controlling the pH of the fertiliser mixture to a specific range (3.5-3.9) during the granulation process. This pH control parameter ensures that zinc oxide remains soluble and reactive, transforming it into a water-soluble form that is readily available to plants, while preventing precipitation and maintaining high micronutrient solubility in the final fertiliser product

Inventive Principle:
Principle #35Parameter changes

2Quantity of substance

If micronutrient is coated onto fertiliser, then micronutrient can be attached to fertiliser particles, but micronutrient loss through abrasion occurs

Engineering Contradiction:
Improvemicronutrient attachmentVSAvoidmicronutrient loss through abrasion
Core Design Contradiction:
Quantity of substanceVSLoss of substance

Solution Approach 1:

The patent merges the micronutrient zinc oxide directly into the fertiliser granule matrix during the granulation process rather than coating it onto the surface. The zinc oxide is incorporated into the bulk of the granule, ensuring uniform distribution and eliminating surface abrasion losses. This integration approach maintains micronutrient attachment while preventing the abrasion-related loss that occurs with surface coating methods

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If bulk blended fertiliser with micronutrient pellets is used, then micronutrient can be distributed in fertiliser, but spatial distribution becomes poor and application to soil becomes uneven

Engineering Contradiction:
Improvemicronutrient distributionVSAvoidspatial distribution uniformity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by controlling the pH during granulation to ensure uniform incorporation of zinc oxide throughout the fertiliser matrix. This results in homogeneous micronutrient distribution at the granule level, which translates to uniform spatial distribution when applied to soil, eliminating the clumping and uneven application problems associated with bulk blending of separate pellets

Inventive Principle:
Principle #35Parameter changes

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

This approach ensures that micronutrients are present in a water-soluble form, improving their availability to plants, allowing for higher concentrations or reduced micronutrient content while maintaining effectiveness, and prevents micronutrient loss through abrasion.

Implementation Method 1

the pH of the fertiliser mixture is measured and controlled in step (a) or in step (b) such that the pH is maintained within a predefined range of between 3.5 and 3.9

Methodology Applied
Scientific EffectpH control:

Implementation Method 2

by controlling the pH such that it is maintained within a predefined range it is possible to ensure that the micronutrient is present in the fertiliser substantially in a water soluble form

Methodology Applied
Scientific EffectDissolution: Solvation

Data Source

PatentEP3016920B2Process for preparing a fertiliser
Publication Date: 2022.06.29 SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ BV
  • EP3016920B2 patent drawingFigure 1
  • EP3016920B2 patent drawingFigure 2
  • EP3016920B2 patent drawingFigure 3

AI summary

A process for preparing a micronutrient-enriched phosphate-based fertiliser is disclosed. An aqueous fertiliser mixture comprising phosphoric acid and/or phosphate rock is prepared and optionally granulated in granulator unit. The pH of the fertiliser mixture is measured and controlled such that the pH is maintained within a predefined range.