Neutral Granular P/K Fertilizer Manufacturing Process
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Solution Overview
Problem
Existing fertilizers like dipotassium phosphate are difficult to store and handle due to hygroscopicity, and there is a lack of easily manufactured, freely flowing, and consistent P/K fertilizers suitable for all situations.
Innovation Solution
A continuous process involving the reaction of concentrated aqueous solutions of phosphoric acid and potassium hydroxide, followed by drying and cooling, to produce a solid, freely flowing P/K fertilizer with a 1:1 weight ratio of P2O5 to K2O, avoiding caking and maintaining a neutral pH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dipotassium phosphate (DKP) and monopotassium phosphate (MPK) are combined to provide P/K elements, then the fertilizer offers desirable solubility and nutrient content, but the hygroscopicity of DKP causes instability and handling difficulties
Solution Approach 1:
The patent changes the physical and chemical parameters of the fertilizer product by controlling the crystallization process to produce a specific crystal structure and composition. The fertilizer is manufactured with a precise P2O5:K2O weight ratio of 1:1 and controlled water content (5-15%), creating a stable granular form that maintains solubility while eliminating hygroscopicity issues through proper crystal formation and moisture control.
2Productivity
If concentrated solutions of phosphoric acid and potassium hydroxide are reacted, then the fertilizer can be manufactured continuously with consistent composition, but the process requires precise control of temperature, pressure, and stoichiometry
Solution Approach 1:
The patent implements feedback control mechanisms throughout the manufacturing process. Temperature is controlled within 85-120°C ranges with feedback from temperature sensors, pressure is maintained at 1-10 bar with continuous monitoring, and the P2O5:K2O ratio is kept at 1:1 through stoichiometric control with analytical feedback. This ensures consistent product composition while enabling continuous operation.
Solution Approach 2:
The patent performs preliminary actions by pre-mixing the phosphoric acid and potassium hydroxide solutions in the correct stoichiometric ratios before reaction, and by pre-establishing the temperature and pressure conditions. This preliminary preparation ensures that when the reaction proceeds continuously, the product composition remains consistent without requiring complex real-time adjustments.
3Ease of operation
If the fertilizer is produced with high water content for better flowability, then the relative fluidity increases, but the tendency to cake and the instability increase
Solution Approach 1:
The patent optimizes the water content parameter to a specific range of 5-15%, which is the critical threshold where the fertilizer achieves adequate flowability (relative fluidity ≥60%) while maintaining compositional stability. This parameter optimization prevents both caking (which occurs at lower moisture) and instability (which occurs at higher moisture), achieving the desired balance through precise control of this key parameter.
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 process results in a stable, non-caking, freely flowing fertilizer with high relative fluidity, suitable for agricultural use, eliminating the handling difficulties of traditional potassium phosphate combinations and providing a consistent source of phosphorus and potassium.
Implementation Method 1
combining said concentrated solutions of step i) in a reactor ensuring a PA/KOH dry weight ratio between 1.14 and 1.22 and a reaction temperature between 85 and 120°C, thereby obtaining a liquid reaction mixture
Implementation Method 2
drying said reaction mixture of step ii) in a vacuum dryer ensuring a reaction temperature between 85 and 120°C and a pressure of at most 400 mbar, whereby obtaining a solid material
Implementation Method 3
drying said reaction mixture of step ii) in a vacuum dryer ensuring a reaction temperature between 85 and 120°C and a pressure of at most 400 mbar
Data Source
AI summary
The invention provides a continuous process for manufacturing an essentially neutral phosphorus/potassium rich fertilizer from basic chemical commodities. The fertilizer is a freely-flowing particulate solid.