Phosphonic Acid Degreasing Solution for Galvanizing Bath Stability
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Solution Overview
Problem
Hot-dip galvanizing baths experience reduced service life due to increasing salt concentration from metal degreasing processes, leading to instability and environmental impact, as existing acidic solutions fail to maintain effective degreasing over time.
Innovation Solution
A degreasing solution containing phosphonic acid or its derivatives is used to adjust salt concentration by forming precipitates, maintaining the degreasing effect and extending bath service life, with optimal concentrations of 0.0001 to 50% phosphonic acid and pH less than 4.0, combined with surfactants and additional acids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If acidic solutions (hydrochloric acid or phosphoric acid) are used to degrease metal surfaces, then the service life of baths is extended, but the salt concentration increases leading to reduced bath stability
Solution Approach 1:
The invention converts the harmful effect of increasing salt concentration into a beneficial process by adding phosphonic acid to precipitate excess metal salts. The salt concentration that would normally degrade bath stability is instead used to form precipitates that can be removed, thereby extending bath service life while maintaining stability.
Solution Approach 2:
The invention changes the chemical parameters of the degreasing bath by introducing phosphonic acid, which alters the precipitation behavior of metal salts. This parameter change allows for controlled salt removal through precipitate formation, enabling extended bath life without compromising stability.
2Productivity
If degreasing is performed repeatedly, then productivity increases, but salt concentration accumulates reducing further degreasing effectiveness
Solution Approach 1:
The invention enables continuous degreasing operations by maintaining bath effectiveness through phosphonic acid addition. The phosphonic acid continuously precipitates accumulating salts, ensuring that the degreasing action remains effective throughout extended operation periods, thus supporting continuous productivity without effectiveness loss.
Solution Approach 2:
The invention facilitates the removal (discarding) of accumulated salt precipitates from the degreasing bath, allowing the useful degreasing action to continue. By periodically removing precipitates, the bath maintains its effectiveness for prolonged periods, enabling sustained high productivity.
3Reliability
If surfactant concentration is increased to maintain degreasing effect, then degreasing performance improves, but environmental impact and waste disposal costs increase
Solution Approach 1:
The invention changes the chemical composition by adding phosphonic acid, which alters the salt precipitation characteristics without requiring increases in surfactant concentration. This parameter change maintains degreasing performance while avoiding the environmental problems associated with high surfactant levels.
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 solution significantly extends the service life of degreasing baths by binding excess iron and removing organic impurities, maintaining effective degreasing over a longer period while minimizing environmental impact and reducing waste disposal costs.
Implementation Method 1
the phosphonic acid and/or the phosphonic acid derivative allows the salt concentration of the solution to be adjusted such that the degreasing effect of the surfactant is maintained for a long time
Implementation Method 2
The solution itself can be used as the bath or added to a solution in the bath during or after a degreasing process to adjust the salt concentration of the bath
Data Source
AI summary
Use of phosphonic acid solution (S1) containing phosphonic acid and/or its derivative for degreasing metal surface e.g. iron or steel surface during hot-dip galvanizing process is claimed. Independent claims are included for the following: (1) degreasing solution used for degreasing metal surface, which contains phosphonic acid and/or its derivative, and a surfactant; (2) use of degreasing solution for degreasing metal surface; and (3) degreasing of metal surface.