Metal recycling

Screening and classification

We are convinced that optimum screening is crucial to the overall success of metal recycling.

SPALECK technology is an important team player in your system. As your partner in metal recycling, SPALECK stands for BEST SCREENING = BEST SORTING.

Because thanks to clean screening, free of impurities and long parts, your magnetic sorters, sensor sorters, air classifiers, X-ray sorters and other sorting technology can perform optimally.

The recycling material is fed into these devices in the best possible way and quality using our conveying and separation technology.

Magnetic sorting

NES sorting

NES sorters | non-ice sorters | eddy current separators | eddy current separators
The next sorting step in metal recycling is the use of eddy current separators. In practice, these are also called NES sorters (non-ferrous sorters) or Eddy Current Separators, or “Eddy” for short.
The aim of NES sorting is to recover the valuable non-magnetic or only weakly magnetic non-ferrous metals from the remaining material stream. These are primarily aluminum, copper, brass, zinc and their alloys. These materials are very important for sustainable and economical recycling.

For this purpose, a conveyor trough feeds and distributes the material onto the conveyor belt of the eddy current separator. The belt is driven on the output side. At the end of the NES sorter is a drum that also rotates quickly and is fitted with permanent magnets. The magnets alternately form a north and a south pole. Due to the high rotation of the drum (usually up to 4,000 rpm), the Eddy Current sorter generates alternating magnetic fields. This generates strong eddy currents in the non-ferrous metals. The result is that these conductive metal parts build up their own magnetic field and are repelled by the alternating fields of the eddy current separator. As the material is transported by the conveyor belt through the rotating magnetic field, the ejected non-ferrous components of the material flow fly further than the non-metallic components, which only have a short trajectory. The separation takes place via a so-called apex: The non-metallic residual materials, such as stones, wood, plastics, cables, metallic composites and also stainless steel with the short trajectory land in the so-called eddy drop, i.e. the residual fraction. The non-ferrous metals end up in the non-ferrous fraction. The purity of the sorting is determined by the position of the apex. Some recyclers use two apexes for this. For example, they can produce a “premium aluminum fraction”, a fraction from a non-ferrous mix and the fraction with the non-metallic residual materials.

Sensor sorting devices

Various types of sorting devices are used in metal recycling. These include, among others:

• Inductive sensor sorting devices
  This technology recognizes metals and metallic composites based on their electrical conductivity and magnetic properties.
• Optical sensors, cameras and 3D sensors (also as combined devices)
  These use the principle of light reflection and/or detect the shape of the material in order to detect additional features of the objects and use them for sorting.
• NIR sorting devices in metal recycling to detect plastic components or composites
  In metal recycling, NIR devices are also used in some applications. For example, NIR technology has proven its worth in separating painted aluminum from unpainted aluminum. NIR sensor technology is also used, for example, to detect PCBs (printed circuit boards) and printed circuit boards.
• X-ray sorting devices
  In metal recycling using X-ray technology, a distinction is made between XRT and XRF sorting devices. XRT stands for the term X-ray transmission and XRF for the term X-ray fluorescence. While XRT systems completely screen the material and detect the material density in comparison to other objects, XRF sorting technology only “screens” the surface of the material to analyze the chemical composition (material type).
• LIBS (Laser Induced Breakdown Spectroscopy)
  The LIBS method is used for the chemical analysis of metals (primarily aluminum alloys) and enables a very high detection accuracy for certain materials.

Shredder heavy fraction (SSF) briefly explained

The shredder heavy fraction (SSF) consists of the heavy metal parts and other heavy materials that are separated from the shredder light fraction (SLF) after shredding or are not contained in the light material stream. The shredder heavy fraction typically consists of steel and iron parts, non-ferrous metals, metallic composites, VA, rubber and plastic from end-of-life vehicles, metallic industrial waste and, for example, white goods from electronic scrap recycling. The aim of the subsequent recycling process is to recover the ferrous and non-ferrous metals so that they can be returned to the material cycle.

Auto Shredder Residue (ASR) what is it?

Auto Shredder Residue, or ASR for short, is the residual fraction (drop) of an eddy current separator. This flow of the eddy current separator (another word for eddy current) usually contains between 20-40% metals and metallic composites, as well as various residual materials. For further processing, recycling companies today often use multi-stage sensor technology to further separate the material and recover the valuable components. The most valuable components are usually stainless steel parts, cables, circuit boards and other metallic composites. The rest consists mainly of rubber, plastics, textile fibers and wood.

What is ZORBA?

Shredded non-ferrous scrap metal

According to the definition of the Institute of Scrap Recycling Industries (ISRI), the main component of Zorba is aluminum (70-90%). It can also contain significant amounts of copper, brass, bronze, stainless steel, nickel, tin and zinc as well as lead and magnesium. The individual components are available in pure or alloyed solid form.

Zorba is produced post magnet by non-ferrous sorting, air classification, flotation, screening or combinations of these techniques. Zorba is generally not yet ready for melting, but is further processed in downstream sorting.

The metal market generally distinguishes between three material sizes for ZORBA – large, medium and small. Zorba is usually sold with a reference to the estimated proportion of its aluminum content and other non-ferrous metals: Zorba 90 thus contains around 90% non-ferrous aluminum as well as other valuable scrap metals such as copper, brass, zinc and lead.

The Zorba material should be as free as possible from other residual materials and waste such as rubber, wood or film, whereby a high level of purity is now demanded by customers worldwide and requires good processing.

Aluminum recycling

The major economic and ecological advantage of aluminum recycling is that only around 5-10% of the energy that would have to be used for primary production for the same amount of aluminum has to be used during melting.

When it comes to aluminum materials, a distinction is made in terms of purity and composition between cast aluminum, wrought aluminum alloys, aluminum sheets, aluminum scrap sheet alloys and so-called taint tabor. Twitch refers to mixed, usually pre-sorted, aluminum bulkheads made from wrought and cast components. The aim of reprocessing is to obtain the highest quality aluminum possible, i.e. free of interfering alloying elements or impurities. Processes such as float-sink separation (so-called DMS – Dense Media Separation) reach their limits, as they can only produce aluminum mixtures. It is not technically possible to separate materials by type based solely on the difference in density.

For this reason, sensor-based technology, e.g. XRT sorting, is generally used as an advanced sorting technique. With these sorting processes, some of which are multi-stage, high purity grades of aluminum scrap (low or reduced in silicon, copper and zinc content) can be produced. The purity of the recycled aluminum is then verified by means of analysis reports, because ultimately what counts here are the right elements and compositions for the target product.

Twitch in metal recycling

Twitch typically refers to mixed aluminum scrap from the car shredder. It is produced, for example, from the processing of Zorba. Magnesium as well as light and heavy metals are separated from the aluminum. The proportion of iron, free zinc and magnesium must each be less than 1%. In addition, a maximum of 2% of other foreign components such as rubber or plastic may be present. In practice, the twitch material is extracted using sensor sorting devices or combination sorting devices. Twitch can also be described simply as a mixture of wrought and cast aluminum with minor impurities.

What is Zurik?

Zurik is shredded non-ferrous scrap. It is usually a metal mixture of metals and composite materials that have been separated (not recognized or sorted) by the eddy current separator (they are also referred to as VA residues or eddy drops). It is separated after the NES sorter using additional sensor sorting technology. Zurik is generally free of iron and is usually present in a purity of 70-80%, depending on how often it has been concentrated. Typical metallic components are stainless steel, insulated copper wire, circuit boards, copper composites, lead, tin and zinc (pure or alloyed) and, where applicable, nickel. This also includes metals that were not correctly recognized by the NES sorter or Eddy Current sorter.

VA residues

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E40 or shredded scrap

E40 is shredded steel scrap. The ferrous material is magnetic and is typically obtained using permanent and/or electromagnets. Iron separation takes place very early on in the recycling process. The material should be as free of foreign matter as possible. It must be free of visible copper (e.g. meatballs), tin and lead (including alloys). Organic components or debris are also viewed critically by foundries, as they make the production of green steel more difficult. For this reason, a chemical analysis of the exact material composition is usually carried out before melting. Meanwhile, a great deal of attention is being paid to cleaning the FE fractions using additional screening machines in order to separate out fines or increase the bulk material. Additional magnets or sensor technology are also used in the iron flow in order to specifically separate metallic impurities.