Magnesium Ammonium Phosphate Recovery via Ion Exchange Filtration

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Solution Overview

Problem

Existing methods for recovering phosphate from phosphorus/phosphate-containing raw sludge are technically complex and inefficient, failing to meet legal requirements for phosphorus recovery while reducing agricultural use of sewage sludge.

Innovation Solution

A simplified method involving decrystallization of magnesium ammonium phosphate into its components, followed by ion exchange and nanofiltration processes to recover phosphate, utilizing ion exchangers and nanofilters to remove and exchange ions, with optional use of acids for crystallization promotion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional methods are used to recover phosphate from phosphorus/phosphate-containing raw sludge, then phosphate recovery is achieved, but the process becomes technically complex and inefficient

Engineering Contradiction:
Improvephosphate recovery efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the phosphate recovery process into distinct functional stages: crystallization of magnesium ammonium phosphate, decrystallization to generate aqueous solution, ion exchange for magnesium removal, and nanofiltration for ammonium removal. This segmentation allows each stage to be optimized independently, simplifying the overall process while improving efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent extracts phosphate from the complex matrix of raw sludge by first converting it to crystalline magnesium ammonium phosphate, then systematically removing interfering ions (magnesium via ion exchange, ammonium via nanofiltration). This extraction approach isolates phosphate from complicating factors, reducing process complexity

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If multiple treatment steps are applied to ensure legal compliance for phosphorus recovery, then compliance is achieved, but the process becomes more complex

Engineering Contradiction:
Improvelegal complianceVSAvoidnumber of treatment steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces crystalline magnesium ammonium phosphate as an intermediary substance that facilitates phosphate recovery. This intermediary allows for systematic ion removal in controlled stages, ensuring legal compliance through predictable, measurable removal efficiencies while maintaining process simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes parameter changes in ion concentration and solution composition at each stage to ensure compliance. By monitoring and controlling magnesium, ammonium, and phosphate concentrations through the sequential processes, the system reliably meets legal requirements without requiring excessive treatment steps

Inventive Principle:
Principle #35Parameter changes

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 achieves efficient recovery of phosphate by simplifying the process and producing high yields of phosphoric acid, demonstrating improved efficiency and compliance with legal requirements.

Implementation Method 1

crystallization of the magnesium ammonium phosphate using an acid, preferably phosphoric acid and/or hydrochloric acid, to generate an aqueous solution in the device

Methodology Applied
Scientific EffectDecrystallization: Crystallisation

Implementation Method 2

The crystallized magnesium ammonium phosphate is then passed to a first device for the removal and/or exchange of ions

Methodology Applied
Scientific EffectAcid dissolution: Hydrolysis

Implementation Method 3

the components can then be gradually removed, for which conventional methods are advantageously provided... the first device for the removal and/or exchange of ions and the removal and/or exchange of Mg2+ in the first device

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 4

the resulting ammonium phosphate is then passed to a second device for the removal and/or exchange of ions, and ammonium is removed from the device... in the second device, the ammonium phosphate passes through an ion exchanger and a nanofilter

Methodology Applied
Scientific EffectNanofiltration: Nanoporous Material

Implementation Method 5

The devices for removing and/or exchanging ions are preferably ion exchangers, nanofilters and adsorption devices

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP4671199A1Process for recovering phosphate
Publication Date: 2025.12.31 HALLERBACH BERND
  • EP4671199A1 patent drawingFigure 1
  • EP4671199A1 patent drawingFigure 2
  • EP4671199A1 patent drawing

AI summary

The invention relates to a process for recovering phosphate present in crystalline magnesium ammonium phosphate. To provide a simplified and efficient process for recovering phosphate present in crystalline magnesium ammonium phosphate (MAP), the invention includes the following process steps: a) providing and feeding existing magnesium ammonium phosphate into a device for crystallization (10) and crystallization of the magnesium ammonium phosphate into its components using an acid, preferably phosphoric acid and/or hydrochloric acid, to generate an aqueous solution (11) in the device (10); b) transferring the crystallized magnesium ammonium phosphate from step a) to a first device for removing and/or exchanging ions (16) and removing and/or exchanging Mg2+ in the first device (16);c) Transferring the resulting ammonium phosphate from step b) into a second device for removing and/or exchanging ions (19) and removing and/or exchanging ammonium in the second device (19).;