Aluminum Alloy Purification by Sn Melt Crystallization Separation
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Solution Overview
Problem
Existing methods are inefficient in reducing or eliminating alloying elements such as Si, Fe, and Cu in aluminum alloys, particularly in wrought materials, which hampers recycling efficiency.
Innovation Solution
A method utilizing the solubility differences in molten Sn to separate and recover solid Al, Si, Fe, and Cu by controlling the melt temperature and crystallization temperatures of Al-Sn, Al-Fe, and Al-Cu compounds, allowing for the recovery of pure Al.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional recycling methods are used for aluminum alloys, then the process is simple, but the alloying elements (Si, Fe, Cu) cannot be effectively removed, limiting the recyclability of wrought materials
Solution Approach 1:
The recycling process is divided into distinct temperature zones: a first temperature range where Al and Si are molten, and a second temperature range where Al crystallizes but Si remains molten. This segmentation allows selective separation of alloying elements at different stages, achieving high purity recycled aluminum while maintaining process feasibility
Solution Approach 2:
The invention utilizes temperature as a controllable parameter to change the physical state of different elements. By precisely controlling the cooling process from the first temperature range to the second temperature range, Al transitions from molten to crystalline state while Si remains molten, enabling effective separation based on differential phase changes
2Manufacturing precision
If the aluminum alloy is cooled to crystallize Al, then Al can be recovered, but Si and other alloying elements remain mixed in the solidified structure
Solution Approach 1:
The invention performs preliminary separation by maintaining Al in molten state while Si is already crystallized and removed in the first temperature range. This preliminary action prevents Si from being incorporated into the solidified Al structure, ensuring clean separation before the final Al recovery stage
Solution Approach 2:
The process dynamically adjusts temperature through two distinct ranges rather than a single cooling step. The transition from first temperature range (Al and Si molten) to second temperature range (Al crystallized, Si molten) creates dynamic separation conditions that prevent contamination of recovered Al with Si and other alloying elements
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 reduces or eliminates Si, Fe, and Cu from aluminum scrap, enhancing recyclability and enabling the production of high-purity aluminum products.
Implementation Method 1
holding the aluminum alloy and Sn at a melt temperature at which the aluminum alloy and Sn are dissolved
Implementation Method 2
lowering the melt temperature, and holding the aluminum alloy and Sn at a Si crystallization temperature at which solid Si is crystallized
Implementation Method 3
further lowering the temperature and holding the aluminum alloy and Sn at an Al crystallization temperature at which Al is crystallized
Data Source
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Figure 3A~4
AI summary
An objective is to provide a method for reducing or eliminating Si in aluminum alloys, and to be able to further reduce or eliminate Fe and Cu components. A method for reducing or eliminating Si contained in an aluminum alloy including: holding the aluminum alloy and Sn at a melt temperature at which the aluminum alloy and Sn are melted; lowering the melt temperature, and holding the aluminum alloy and Sn at a Si crystallization temperature at which solid Si is crystallized while maintaining a molten state of Sn and Al, and separating the solid Si; and further lowering the temperature and holding the aluminum alloy and Sn at an Al crystallization temperature at which Al is crystallized and Sn is in the molten state, to separate and recover solid Al.