Cation Exchange Phosphate Recovery for Pure Phosphoric Acid
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Solution Overview
Problem
Existing methods for recovering phosphate from wastewater in the form of brushite and struvite are not economically viable due to contamination issues and the difficulty in separating phosphoric acid from solid by-products like gypsum and magnesium sulfate, limiting their use as commercial fertilizers.
Innovation Solution
A method using a solid, acid-charged cation exchanger to dissolve brushite and struvite in acidic solutions, allowing for easy separation of phosphoric acid from solid contaminants by filtration, thereby producing a pure phosphoric acid product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods using iron and aluminum salts are used to precipitate phosphate, then phosphate removal is achieved, but struvite crystal formation is inhibited and additional chemicals are required
Solution Approach 1:
The patent extracts and removes struvite crystals from the wastewater stream through filtration and centrifugation, separating them from the liquid effluent. This extraction approach allows phosphate recovery without requiring additional iron or aluminum salts, as the struvite is directly isolated from the wastewater.
Solution Approach 2:
The patent introduces a filtration system and centrifugal separation device as intermediaries to separate struvite crystals from the wastewater. These mechanical separation devices act as mediators that enable phosphate recovery without requiring chemical precipitation agents, thereby simplifying the overall process.
2Quantity of substance
If struvite crystals are formed in wastewater treatment plants, then phosphate recovery is achieved, but crystal accumulation in pipes causes flow reductions
Solution Approach 1:
The patent applies preliminary action by removing struvite crystals from the wastewater stream before they can accumulate in pipes and cause flow restrictions. The filtration and centrifugal separation processes are implemented early in the treatment sequence, preventing the crystals from migrating downstream and clogging the system.
Solution Approach 2:
The patent extracts struvite crystals from the wastewater stream through mechanical separation devices, removing them before they can cause pipe accumulation. This extraction approach directly addresses the flow reduction problem by eliminating the crystals that would otherwise settle and block the wastewater system.
3Quantity of substance
If brushite and struvite are used as phosphate sources, then phosphate recovery from wastewater is achieved, but separation of phosphoric acid from solid by-products is difficult
Solution Approach 1:
The patent introduces mechanical separation devices (filtration systems and centrifuges) as intermediaries to separate phosphoric acid from solid by-products. These devices provide a simple and effective separation mechanism that avoids complex chemical processing, making the manufacturing process easier and more economically viable.
Solution Approach 2:
The patent replaces complex chemical separation methods with mechanical separation systems. By using filtration and centrifugal force, the patent achieves efficient separation of phosphoric acid from solid by-products, eliminating the need for complex chemical processing steps and simplifying the overall manufacturing process.
4Object-affected harmful factors
If phosphate is recovered from wastewater, then environmental pollution is reduced, but the recovered phosphate is contaminated and cannot be used as commercial fertilizer
Solution Approach 1:
The patent extracts struvite crystals from the wastewater stream through mechanical separation, obtaining a relatively pure solid product. This extraction approach, combined with subsequent processing steps, enables the production of high-purity phosphate suitable for commercial fertilizer use while maintaining the environmental benefits of wastewater treatment.
Solution Approach 2:
The patent uses mechanical separation systems (filtration and centrifugation) to achieve high-purity phosphate recovery. These mechanical methods provide effective separation that produces commercially viable fertilizer-grade phosphate, overcoming the contamination issues associated with conventional wastewater recovery methods.
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 method effectively produces uncontaminated phosphoric acid, simplifies the separation process, and enables the use of brushite and struvite as high-grade phosphorus fertilizers, reducing processing costs and environmental impact.
Implementation Method 1
contacting at least one mineral with a cation exchanger for a time and at a temperature sufficient to yield phosphoric acid from the mineral
Implementation Method 2
allowing for easy separation of phosphoric acid from solid contaminants by filtration
Data Source
AI summary
A method of producing ammonium phosphates from at least one mineral containing phosphate and an element which is calcium, magnesium, iron, or aluminum. The method includes contacting the at least one mineral (or a combination of them) with a cation exchanger for a time and at a temperature sufficient to yield phosphoric acid from the mineral.