Vibrating Conveyor Dezincification of Galvanized Steel Scrap
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Solution Overview
Problem
Current methods for recycling galvanized steel scrap are economically and ecologically inefficient due to high zinc losses during melting, and existing dezincification processes require high temperatures or result in excessive iron dissolution.
Innovation Solution
A method using a vibrating conveyor to continuously move scrap through a liquid, such as sulfuric acid, which accelerates zinc dissolution while minimizing iron loss, utilizing a combination of vertical and horizontal vibrations to ensure complete coating detachment and controlled contact time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If alkaline solution dezincification is used, then zinc can be removed from scrap, but significantly higher temperature of at least 85°C over a relatively long period of time is required
Solution Approach 1:
The patent changes the chemical parameter of the dezincification solution from alkaline to acidic, which fundamentally alters the reaction conditions. This parameter change allows the process to proceed at lower temperatures while maintaining effective zinc removal, as the acidic solution provides a different chemical mechanism for zinc dissolution that is less temperature-dependent
Solution Approach 2:
The patent introduces an intermediary substance - an oil layer - on top of the acidic solution. This intermediary prevents iron dissolution by creating a protective barrier, while allowing zinc to be removed. This mediator enables the process to achieve zinc removal without the harmful side effect of excessive iron dissolution that would otherwise occur at lower temperatures
2Duration of action of moving object
If acidic dezincification is used, then dezincification takes place within a shorter time and at lower temperatures, but considerable amounts of iron are dissolved with the acid treatment
Solution Approach 1:
The patent introduces an intermediary substance - an oil layer - on top of the acidic solution. This intermediary prevents iron dissolution by creating a protective barrier, while allowing zinc to be removed. This mediator enables the process to achieve zinc removal without the harmful side effect of excessive iron dissolution that would otherwise occur at lower temperatures
Solution Approach 2:
The patent creates different local conditions within the treatment system: the acidic solution environment for zinc removal, protected by an oil layer that creates a different local environment at the surface that prevents iron dissolution. This spatial differentiation of chemical environments allows selective removal of zinc while protecting iron
3Productivity
If continuous process is used, then higher throughput is achieved, but precise control of reaction times is required to keep iron dissolution within acceptable limits
Solution Approach 1:
The patent employs a vibrating conveyor that dynamically moves scrap through the treatment zones. The vibration frequency, amplitude, and conveyor speed can be adjusted to control the residence time of scrap in the acidic solution. This dynamic system allows precise control of reaction time while maintaining continuous operation and high throughput
Solution Approach 2:
The patent implements a controlled process where parameters such as conveyor speed, vibration characteristics, and solution composition can be monitored and adjusted to maintain optimal reaction conditions. This feedback control ensures that iron dissolution remains within acceptable limits while maximizing productivity
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 efficient, continuous dezincification with reduced iron contamination, allowing for effective recovery of zinc and promoting the recycling of galvanized steel scrap, enhancing both economic and environmental sustainability.
Implementation Method 1
The presence of zinc ions in the acidic solution leads to a significant acceleration of the zinc dissolution
Implementation Method 2
A method using a vibrating conveyor to continuously move scrap through a liquid
Data Source
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AI summary
The invention relates to a method for detaching coatings from scrap (3), wherein the scrap (3) is brought into contact with a liquid and, when detaching the coating, the scrap (3) is moved in a conveying trough (2) of a vibrating conveyor (1) along a conveying direction (6) from the inlet end (7) to the outlet end (8) of the conveying trough (2). The invention is of particular importance for the removal of zinc from steel scrap. The method is performed continuously and brings about efficient detachment of the coatings.