ALUMINIUM RECYCLING

Effective recovery and quality improvement for aluminium scrap

Make secondary aluminium profitably with advanced sorting of different aluminium fractions from recycling processes

As a lightweight, high-performance material, aluminium is increasingly replacing steel, particularly in automotive engineering. This also makes the recovery of this metal interesting as a value-creating process. Aluminium waste has a wide bandwidth of material compositions and fractions. They come from a wide range of built-in products and components. As alloy components, silicon, manganese, copper, zinc and magnesium increase the strength of the aluminium and determine the primary and secondary uses of plate, rods and tubes, etc. The composition of alloys also determines the ‘castability’ - which is an advantage for complex components such as alternators. The best castability is that of AlSi compounds (4000 class). In some cases these also contain elements of Mg and Cu to increase strength.

Profiles, cans, plates etc. in wrought aluminium are normally low in alloy components and can be used in almost all secondary processes. In the mechanical recovery of wrought aluminium, the main task is separation of heavy metal components and commingled waste, which are exposed during shredding, e.g. by hammer mill or rotary shear. Iron components are separated here by means of magnets (STEINERT UME and BR). For fractions of profiles, cans and food containers, wet mechanical separation of the free heavy metals and higher-alloy Al components (cast components) is generally not worthwhile in economic terms. Here our dry mechanical sorting by atomic density using the STEINERT XSS T is a reliable alternative to sink/float separation, or as a system addition for sorting off higher-alloy aluminium and free heavy metals, thereby enabling aluminium purity levels of >99.5% to be obtained.

High-quality aluminium from product cycles with low alloy components, filler metals or light element content such as magnesium can be upgraded into very pure products using laser-induced breakdown spectroscopy (LIBS). Our STEINERT KSS LI sorts the objects by chemical composition with high selectivity to your requirements. Additionally our secondary smelter solution gives you the opportunity of using more secondary material and to charge the smelt on the basis of alloys.

A particular feature is the detection and separation of painted aluminium plate before smelting in order to remove traces of titanium dioxide or even lead and cadmium from the paint and coatings. Here our STEINERT KSS FLNR unit analyses the material surface by colour, laser or infrared detection. The relevant items are separated off for separate treatment.

In the case of aluminium from the auto shredder, this is primarily higher-alloyed material containing 4 to 12% silicon plus primarily copper and zinc. The greater the Si content, the less ductile is the component, which will break up during shredding into many smaller pieces. We use this property in our solution and sort the non-ferrous product flow of the shredder in grain sizes e.g. 10 - 30 mm, 30 - 70 mm and 70 - 150 mm using a non-ferrous metal separator (STEINERT EddyC®) into what is known as the “ZORBA fraction”. This mixture of light and heavy metals is now separated by grain size using x-ray technology (STEINERT XSS T) into aluminium and the group fraction of copper, brass, zinc, etc. This achieves a maximum yield and purity of aluminium and the material can be marketed in a defined quality, e.g. 224, or coarse grain sizes as Taint Tabor (mainly clean sheet goods). Against a background of increasingly difficult export conditions to the Far East it is important to achieve consistently high purity levels across all products.

The need to sort within alloy classes, e.g. between the 5000 and 6000 classes of wrought alloy commonly used in carmaking, represents a particularly high demand on the depth of analysis of detection. Here the main difference is in the magnesium and silicon content in the alloys, which determine the material properties relevant to the components. The necessary quantitative determination of these alloy components can be performed today using the laser-induced breakdown spectroscopy (LIBS) method. In principle this can also be used to quantitatively determine all the alloy components of significance for the aluminium alloy groups 1000 to 7000.

Our STEINERT LSS combines the superb possibilities of LIBS technology with material separation and product discharge within a system unit designed for industry. 

  • All magnet and sensor sorting technology from a single source
  • Longevity of all sorting machine components
  • Ferrous and non-ferrous metals, separation with magnet and eddy-current technology
  • Alloy detection, detection of heavy and light elements with x-ray technology
  • Extended alloy sorting, discrimination between cast and wrought alloy with laser technology (LIBS)
  • Purity of sorted products, high selectivity and detection

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Zorba from large shredders
Aluminium profiles
Mixed light aluminium scrap
Twitch aluminium alloy sorting
Aluminium cans from waste

The perfect solution for your requirements

STEINERT BR

Extracting ferromagnetic materials

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STEINERT UME

Effective capture of ferrous parts from large layer thicknesses

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STEINERT MTP

For separating iron from medium coarse to fine bulk materials

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STEINERT EddyC®

For the separation of non-ferrous metals

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STEINERT XSS® T

For sorting into density classes

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STEINERT KSS FLIXT

For sorting using colour, 3D, metal and density detection

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STEINERT LSS

For sorting using 3D detection and either LIBS or x-ray fluorescence detection

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