Coherent Dispersible Granules for Stronger Phosphorus Adsorption
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Solution Overview
Problem
Existing methods for producing dispersible granules with metal oxides and phosphates suffer from limitations such as limited crush strength, intergranular variability, and inefficient interaction between metal oxide and phosphate domains, leading to suboptimal phosphorus adsorption and runoff mitigation.
Innovation Solution
The formation of coherent dispersible granules with distinct metal oxide and phosphate domains through co-agglomeration processes, including methods like reacting phosphoric acid with ammonia and introducing metal oxide particles into a rotary drum ammoniator-granulator, results in granules with enhanced crush strength and reduced intergranular variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal oxide particles and phosphate domains are agglomerated into dispersible granules, then phosphorus adsorption efficiency is improved, but granule crush strength is limited
Solution Approach 1:
The patent changes the physical and chemical parameters of the granulation process by controlling pH, moisture content, and mixing conditions to enable coherent binding between metal oxide particles and phosphate domains. This allows the granules to achieve both high crush strength (≥5 lbf) and effective phosphorus adsorption capacity through optimized process parameters rather than just physical mixing
Solution Approach 2:
The patent creates composite dispersible granules combining metal oxide particles (such as aluminum oxide, iron oxide, or calcium oxide) with phosphate domains (MAP, DAP, granulated TSP, or granulated SSP) in a coherent structure. This composite material approach allows the granules to simultaneously exhibit the crush strength of bound granules and the phosphorus adsorption capability of metal oxide-phosphate combinations
2Reliability
If complex agglomeration processes are used to combine metal oxide with phosphate products, then phosphorus adsorption is enhanced, but manufacturing complexity increases and granule size is limited
Solution Approach 1:
The patent merges the metal oxide addition step with the existing phosphate granulation process by introducing metal oxide particles during the granulation operation itself, rather than requiring separate agglomeration steps. This integration approach combines multiple functions (granulation and metal oxide incorporation) into a single process operation, reducing overall manufacturing complexity while achieving enhanced phosphorus adsorption capacity
3Reliability
If metal oxide particles are added to existing phosphate granules, then phosphorus adsorption is improved, but intergranular variability increases
Solution Approach 1:
The patent applies preliminary action by pre-mixing metal oxide particles with the phosphate slurry or semi-dry mixture before final granulation, ensuring uniform distribution of metal oxide throughout the granule mass. This preliminary mixing step prevents clumping and ensures consistent metal oxide-phosphate contact in each granule, reducing intergranular variability in phosphorus adsorption performance
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 coherent dispersible granules exhibit improved crush strength, reduced moisture content, greater hygroscopic stability, and enhanced interaction between metal oxide and phosphate domains, leading to more efficient phosphorus adsorption and reduced runoff.
Implementation Method 1
Metal oxide-based materials are well-documented to aid in the adsorption and selective, slow-release desorption of orthophosphates in soils
Implementation Method 2
phosphoric acid is mixed with about 93 wt % sulfuric acid in an acid surge tank... The mixed acids are then fed into a brick-lined acid reactor, where they are partially neutralized with liquid or gaseous anhydrous ammonia
Implementation Method 3
Agglomeration occurs in the rotating drum and is terminated in the dryer
Data Source
AI summary
Coherent dispersible granules are disclosed including at least one metal oxide domain and at least one phosphate domain, wherein the at least one metal oxide domain and the at least one phosphate domain are present in the coherent dispersible granules as distinct domains coherently agglomerated together and the coherent dispersible granules have a coherent dispersible granule crush strength of at least 5 lbf. Methods for forming the coherent dispersible granules are disclosed, including co-agglomerating at least one of ammonium phosphate, superphosphate slurry, or nitrophosphate slurry and the metal oxide particles in a rotary drum ammoniator-granulator or granulator to form coherent dispersible granules, and drying the coherent dispersible granules.