Ammonium Phosphate Production via Liquid-Liquid Extraction
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Solution Overview
Problem
The production of ammonium phosphates from phosphorus-containing solutions is energy-intensive and costly due to the need for concentrating phosphoric acid by water evaporation, resulting in contaminated products unsuitable for applications like fertigation.
Innovation Solution
A method involving the extraction of phosphorus into a water-immiscible liquid phase, followed by the addition of anhydrous ammonia to precipitate mono-ammonium or di-ammonium phosphate, which are then extracted and controlled within a specific temperature range, allowing for the production of fully-soluble ammonium phosphates without the need for water evaporation and ammonia scrubbing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If phosphoric acid is concentrated by water evaporation to produce merchant-grade phosphoric acid, then the acid concentration is improved, but energy consumption increases and the product contains heavy metal contaminants
Solution Approach 1:
The patent extracts phosphoric acid from the aqueous phase into an organic solvent phase through liquid-liquid extraction, separating it from water and heavy metal contaminants without requiring energy-intensive evaporation. The phosphoric acid is taken out of the contaminated aqueous solution and transferred to the organic phase, achieving concentration and purification simultaneously.
Solution Approach 2:
The patent uses an organic solvent as an intermediary substance to transfer phosphoric acid from the aqueous phase to the organic phase. This intermediary enables the separation and concentration of phosphoric acid without direct heating or evaporation, avoiding energy consumption and heavy metal contamination in the final product.
2Manufacturing precision
If phosphoric acid is purified by solvent extraction followed by back extraction with water, then the purity is improved, but the phosphoric acid becomes dilute and requires additional evaporation
Solution Approach 1:
Instead of the conventional approach of extracting phosphoric acid into organic solvent then back-extracting with water (which produces dilute acid), the patent inverts the process by directly neutralizing the phosphoric acid in the organic phase with ammonia to form ammonium phosphate. This inversion eliminates the need for back extraction and subsequent re-concentration, maintaining both purity and avoiding dilution.
Solution Approach 2:
The patent discards the conventional back extraction step with water that causes dilution, and instead recovers the phosphoric acid directly in the organic phase by neutralizing it with ammonia to form ammonium phosphate product. This eliminates the need for additional evaporation while maintaining purity.
3Reliability
If ammonia is added to phosphoric acid in multiple stages with water addition for cooling, then the neutralization is controlled, but the process complexity and equipment requirements increase
Solution Approach 1:
The patent merges multiple process steps into a single operation: ammonia is added directly to the phosphoric acid in the organic phase, and the reaction heat is utilized to evaporate excess ammonia and water in situ. This combines neutralization, cooling, and concentration into one step, reducing equipment complexity while maintaining control through the exothermic reaction itself.
Solution Approach 2:
The patent employs self-service by using the heat generated from the neutralization reaction itself to evaporate excess ammonia and water. The reaction's own exothermicity provides the energy needed for ammonia removal and concentration, eliminating the need for external cooling systems and complex equipment while maintaining process control.
4Temperature
If water is added to reactors to remove excess heat during neutralization, then the temperature is controlled, but the slurry requires additional evaporation and drying
Solution Approach 1:
The patent utilizes phase transition by allowing the exothermic neutralization reaction to generate heat that directly evaporates water and excess ammonia from the system. The temperature control achieved through this evaporation process eliminates the need for additional water addition, and the phase change from liquid to vapor removes moisture without requiring separate evaporation or drying steps.
Data Source
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AI summary
A method for production of ammonium phosphates comprises providing (210) of a phosphorus-loaded water immiscible liquid phase, adding (212) of anhydrous ammonia to the water immiscible liquid phase, precipitating (214) of mono-ammonium phosphate and/or di-ammonium phosphate from the water immiscible liquid phase and extracting (218) of the precipitated mono-ammonium phosphate and/or di-ammonium phosphate from the water immiscible liquid phase. The method further comprises controlling (216) of a temperature of the water immiscible liquid phase during the adding (212) and precipitating (214) to a predetermined temperature interval.