Ammonium Polyphosphate Fertilizer with Polyurethane Coating
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Solution Overview
Problem
Current phosphate fertilizers have low utilization rates due to rapid immobilization in soil, lack of medium and trace elements, and insolubility issues, leading to inefficient nutrient absorption by plants.
Innovation Solution
A controlled release fertilizer containing ammonium polyphosphate with a degree of polymerization between 5 to 20, coated with polyurethane, which includes nitrogen, potassium, and multiple medium and trace elements, ensuring slow and sustained release of phosphorus and trace elements, preventing precipitation and improving solubility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If water-soluble phosphate fertilizer is used to provide quick fertilization effect, then phosphorus availability to plants is improved, but phosphorus is rapidly fixed by soil colloids and hypervalent cations, reducing utilization rate
Solution Approach 1:
The patent changes the chemical form of phosphorus from orthophosphate to polyphosphate, altering its polymerization degree (n=6-30) to modify solubility and release characteristics. This parameter change allows phosphorus to remain soluble enough for plant uptake while resisting rapid fixation by soil colloids and cations, thereby maintaining both quick effect and high utilization rate
Solution Approach 2:
The patent creates a composite fertilizer system combining polyphosphate with specific ratios of nitrogen (15-30%), phosphorus (10-20%), potassium (10-20%), and trace elements. This composite formulation enhances phosphorus availability while preventing rapid fixation, achieving both fast action and sustained effectiveness
2Ease of operation
If phosphate fertilizer is evenly distributed in soil to facilitate root absorption, then phosphorus accessibility to roots is improved, but fixation by soil increases, reducing fertilization efficiency
Solution Approach 1:
By changing phosphorus from orthophosphate to polyphosphate form and controlling polymerization degree (n=6-30), the patent reduces phosphorus fixation by soil colloids while maintaining solubility. This allows even distribution in soil without proportionate increase in fixation losses, improving both root accessibility and overall fertilization efficiency
3Reliability
If polyphosphate with high degree of polymerization is used to reduce water solubility and prevent fixation, then phosphorus retention in soil is improved, but water solubility decreases, reducing quick fertilization effect
Solution Approach 1:
The patent optimizes the polymerization degree parameter to a specific range (n=6-30), balancing solubility and fixation resistance. This controlled parameter adjustment ensures sufficient water solubility for quick plant uptake while maintaining enough polymerization to prevent rapid fixation, achieving both fast action and phosphorus retention
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 fertilizer achieves a higher utilization rate of phosphorus and trace elements, enhancing crop nutrition and yield while reducing costs and environmental impact.
Implementation Method 1
slow and sustained release of phosphorus and trace elements
Implementation Method 2
improving solubility
Implementation Method 3
coated with polyurethane, which includes nitrogen, potassium, and multiple medium and trace elements, ensuring slow and sustained release
Data Source
AI summary
A controlled release fertilizer containing ammonium polyphosphate includes fertilizer core particles and fertilizer envelopes coated on a surface of the fertilizer core particles respectively. P (phosphorus) is only from ammonium polyphosphate, and ammonium polyphosphate has a degree of polymerization in a range of 5 to 20. A preparation method of the controlled release fertilizer includes steps of (1) weighing the phosphorus source, the nitrogen source, the potassium source and the multiple metallic medium and trace element sources in the above weight parts, pulverizing, and obtaining powders by sieving through a sieve with a mesh number of 80; (2) preparing fertilizer core particles; (3) preparing polyurethane envelopes on a surface of the fertilizer core particles respectively, and (4) adding the agglomerant in the above weight parts into the fertilizer core particles coated with the polyurethane envelopes and cooling to 20° C.