Chemical Milling Bath Regeneration by Aluminosilicate Precipitation

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Solution Overview

Problem

The chemical milling of aluminum semi-finished products faces challenges with the high cost and environmental impact of spent bath disposal due to high aluminum concentrations, which require frequent restoration and disposal, leading to inefficiencies and increased operational costs.

Innovation Solution

A regeneration process is introduced that precipitates aluminosilicates by adding a source of silicon to the spent solution, forming zeolites, which reduces aluminum concentration and allows the bath to be reused, thereby minimizing disposal and restoring sodium hydroxide levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If chemical milling solutions are used repeatedly, then operational cost is reduced, but solution effectiveness deteriorates due to contaminant buildup

Engineering Contradiction:
Improveoperational costVSAvoidsolution effectiveness
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the milling solution by adjusting pH levels, adding specific chemicals, and controlling temperature to restore effectiveness. The system monitors solution chemistry and makes real-time parameter adjustments to maintain etching capability while extending solution life.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent recovers valuable components from spent milling solution through filtration, chemical treatment, and concentration processes. Contaminants are removed and useful chemicals are recovered and reused, reducing waste disposal costs and operational expenses while maintaining solution effectiveness.

Inventive Principle:
Principle #34Discarding and recovering

2Duration of action of stationary object

If filtration systems are added to remove contaminants, then solution life is extended, but system complexity increases

Engineering Contradiction:
Improvesolution lifeVSAvoidsystem complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines multiple functions into integrated filtration and treatment units that perform particle removal, chemical regeneration, and fluid circulation in a single compact system. This merging reduces the number of separate components and simplifies system operation while effectively extending solution life.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system incorporates automatic filtration and regeneration capabilities that operate without continuous manual intervention. Sensors monitor solution quality and trigger filtration cycles automatically, reducing operational complexity while maintaining extended solution life through consistent contaminant removal.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If solution volume is increased to maintain concentration, then etching precision is maintained, but material waste increases

Engineering Contradiction:
Improveetching precisionVSAvoidmaterial waste
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

Instead of increasing volume to maintain concentration, the system changes other parameters such as temperature, pH, and additive concentrations to preserve etching precision. This allows maintaining effective etching performance with reduced solution volume, thereby reducing material waste.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system recovers and concentrates useful chemicals from large volumes of spent solution, extracting valuable etchants and reagents for reuse. This recovery process reduces the need to dispose of large volumes of solution while maintaining etching precision through controlled replenishment of active ingredients.

Inventive Principle:
Principle #34Discarding and recovering

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 process effectively reduces aluminum concentration, enabling the reuse of the milling bath and produces valuable zeolites, thus reducing disposal costs and environmental impact while maintaining process efficiency.

Implementation Method 1

a centrifugal separation system which receives the chemical milling solution and separates suspended particles from the chemical milling solution

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 2

an ion exchange system which receives the chemical milling solution and removes ionic contaminants from the chemical milling solution by ion exchange

Methodology Applied
Scientific EffectIon exchange: Ion Exchange

Implementation Method 3

an evaporation system which receives the chemical milling solution and concentrates the chemical milling solution by evaporation of solvent

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4526492B1Process for regenerating chemical milling solutions
Publication Date: 2026.05.20 GREEN ETCHING SRL
  • EP4526492B1 patent drawingFigure 1
  • EP4526492B1 patent drawing

AI summary

A process for regenerating chemical milling solutions, comprising the steps of introducing a reagent containing silicon into a solution in such a way as to establish a molar ratio of Si/ Al equal to 1 in the solution, and letting the silicon and aluminum in solution react, up until the formation of a phase containing aluminosilicates.