Potassium Phosphate Production via Solvent Extraction and Stripping
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Solution Overview
Problem
Current methods for producing potassium phosphates are energy-intensive, require expensive equipment, and result in impure, non-soluble products due to the need for water evaporation and neutralization with potassium hydroxide or carbonate, which are not suitable for chloride-sensitive crops and require additional processing to avoid clogging in fertigation and foliar applications.
Innovation Solution
A method involving liquid-liquid extraction of phosphoric acid using a water-immiscible solvent like tributyl phosphate, followed by stripping with a potassium phosphate solution, and recirculating the solvent for further extraction, eliminating the need for water evaporation and producing pure, fully-soluble mono- or di-potassium phosphate without precipitates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If merchant-grade phosphoric acid is neutralized with potassium hydroxide or carbonate, then potassium phosphates are produced, but the products contain impurities and are not fully soluble
Solution Approach 1:
The patent applies preliminary action by performing liquid-liquid extraction to purify phosphoric acid before neutralization. The feed liquid undergoes extraction with an organic solvent to remove impurities, and the extracted phosphoric acid is then neutralized with potassium carbonate to produce high-purity, fully-soluble potassium phosphate without precipitates.
2Quantity of substance
If water is evaporated to produce merchant-grade phosphoric acid, then high acid concentration is achieved, but energy consumption increases
Solution Approach 1:
The patent applies extraction by using liquid-liquid extraction with an organic solvent to concentrate phosphoric acid from the feed liquid. This alternative to evaporation achieves the required acid concentration for neutralization without the high energy consumption associated with water evaporation, thereby reducing energy costs while maintaining product quality.
3Quantity of substance
If potassium chloride is used as fertilizer source, then potassium supply is provided, but chloride-sensitive crops are harmed
Solution Approach 1:
The patent applies parameter changes by producing potassium phosphate instead of using potassium chloride. The neutralization of phosphoric acid with potassium carbonate yields potassium phosphate (KH2PO4 or K2HPO4), which provides the necessary potassium content for fertilization while eliminating harmful chloride ions, making it suitable for chloride-sensitive crops.
4Ease of operation
If potassium phosphates are produced for fertigation, then soluble fertilizer is provided, but equipment clogging occurs with impure products
Solution Approach 1:
The patent applies preliminary action by purifying phosphoric acid through liquid-liquid extraction before neutralization. This removes impurities that would otherwise form precipitates during neutralization, ensuring the resulting potassium phosphate is fully soluble and will not clog fertigation equipment, thereby maintaining system reliability.
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
Enables the production of high-purity, fully-soluble potassium phosphates efficiently and economically, reducing energy consumption and equipment costs, suitable for chloride-sensitive crops and fertigation applications without clogging, and avoiding the use of ammonia, which is easier to handle than potassium hydroxide.
Implementation Method 1
liquid-liquid extraction of phosphoric acid using a water-immiscible solvent like tributyl phosphate
Implementation Method 2
stripping with a potassium phosphate solution
Implementation Method 3
The neutralization of merchant-grade phosphoric acid with potassium hydroxide or potassium carbonate is an exothermic reaction
Data Source
AI summary
An arrangement for production of fully soluble, pure and well-defined mono- or di-potassium phosphates, comprises an extraction section, a stripping section and end treatment arrangements. The extraction section performs a liquid-liquid extraction of phosphate between a feed liquid comprising phosphoric acid. The stripping section performs a liquid-liquid extraction of phosphate between solvent loaded with phosphate and a strip solution. The solvent depleted in phosphate is recirculated to the extraction section for further extraction of phosphate. The strip solution is an aqueous potassium phosphate solution. The end treatment arrangements comprise a source of potassium base, an adding arrangement, a cooling arrangement, a precipitate remover and a recirculation system.