Aluminum Scrap Sorting via X-Ray Transmission Density

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Solution Overview

Problem

Existing mechanical methods for processing aluminum scrap fail to achieve high purity levels due to high energy consumption and inefficiencies, while chemical methods are energy-intensive and costly, and X-ray fluorescence spectroscopy-based sorting is unreliable and slow.

Innovation Solution

A method involving comminution, screening, and X-ray transmission-based density determination to separate aluminum scrap into fractions, using X-ray transmission to sort materials by density, thereby achieving high purity with reduced energy consumption and environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If chemical processes are used to melt down and separate aluminum scrap, then purity of aluminum is improved, but energy expenditure increases considerably

Engineering Contradiction:
Improvepurity of aluminumVSAvoidenergy expenditure
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent replaces chemical melting and separation processes with a mechanical sorting system based on X-ray fluorescence spectroscopy. The system uses an X-ray source to excite aluminum particles on a conveyor belt, detects characteristic fluorescence radiation with photomultiplier tubes, and uses pneumatic nozzles to separate particles by composition. This mechanical/optical method achieves high purity separation without the considerable energy expenditure of chemical processes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the separation parameter from chemical composition analysis through melting to physical property analysis through X-ray fluorescence. By measuring the intensity of characteristic radiation at specific wavelengths, the system identifies aluminum alloy composition and separates particles based on their spectral signature, achieving purification through physical rather than chemical means.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If X-ray fluorescence spectroscopy is used for sorting aluminum scrap, then material separation is achieved, but error rate is unacceptably high and process speed is unsatisfactory

Engineering Contradiction:
Improvematerial separation accuracyVSAvoiderror rate and process speed
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent prepares the aluminum scrap by crushing and conveying it as individual particles on a moving belt before analysis. This preliminary preparation ensures that each particle is presented individually to the X-ray source and detectors, allowing for accurate spectral analysis and rapid pneumatic ejection of unwanted materials. The continuous conveyor system enables high-speed processing with minimal error rates.

Inventive Principle:
Principle #10Preliminary action

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 high aluminum purity with reduced energy use and environmental impact, allowing for efficient separation of aluminum from other metals and alloys, and enables precise sorting of unwanted materials, resulting in a more reliable and faster process compared to X-ray fluorescence spectroscopy.

Implementation Method 1

density determination by X-ray transmission in an X-ray device

Methodology Applied
Scientific EffectX-ray transmission: X-Ray

Implementation Method 2

the intensity of the exit radiation is detected by means of a sensor, an intensity comparison is carried out between the incoming and outgoing X-ray radiation and the difference in radiation intensity is determined

Methodology Applied
Scientific EffectAbsorption of X-ray radiation: Absorption (EM radiation)

Implementation Method 3

material particles with a density above a predefinable limit value are pneumatically sorted out from the material being sorted

Methodology Applied
Scientific EffectPneumatic sorting:

Data Source

PatentEP3336208B1Method for the mechanical processing of aluminium scrap
Publication Date: 2019.08.28 HYDRO ALUMINUM RECYCLING DEUT GMBH
  • EP3336208B1 patent drawingFigure 1
  • EP3336208B1 patent drawingFigure 2

AI summary

To create a method for the mechanical processing of aluminum scrap that achieves high purity levels of the reusable aluminum while requiring comparatively low energy, the invention proposes a method for the mechanical processing of aluminum scrap (1) in which, in a first step, the aluminum scrap (1) undergoes a two-stage comminution, wherein in the first comminution stage particles with a cubic, spherical shape are formed and in the second comminution stage, which serves as a secondary comminution, particles with a disc-shaped shape are formed, wherein in a second step the comminution of the aluminum scrap (1) is fed to a screening plant (7) and separated into a fraction of undersized materials (9) on the one hand and a fraction of oversized materials (11) on the other hand.in which, in a third step, the fraction of oversized materials (11) is homogenized, in which, in a fourth step, the homogenized fraction of oversized materials (11) is subjected to density determination by means of X-ray transmission in an X-ray device (34), in which, in a fifth step, material particles with a density above a predefinable limit value are pneumatically sorted out from the sorted material.