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How a Scrap Metal Collection Company Separates Metals

by Mercedesz

Separating different types of metals is one of the key processes in a scrap metal collection company. Proper sorting ensures that metals are recycled efficiently and can be sold for maximum value. Scrap metal collection companies employ a variety of methods to separate ferrous and non-ferrous metals, as well as distinguish between different grades and types. Here’s a look at how scrap metal collection companies separate metals:

1. Magnetic Separation: Distinguishing Ferrous and Non-Ferrous Metals

The first step in metal separation is typically sorting ferrous metals (those containing iron) from non-ferrous metals. This is done using magnets.

  • Ferrous Metals: These are magnetic and include materials like iron and steel. When a magnet is applied, ferrous metals are easily attracted, making them straightforward to separate.
  • Non-Ferrous Metals: Non-ferrous metals, such as copper, aluminium, brass, and lead, are not magnetic. These metals are separated from ferrous metals after the magnetic process, as they will not react to the magnet.

Magnetic separation is one of the most basic and essential steps in metal sorting and can be done on a large scale in scrapyards with powerful conveyor magnets that automatically separate ferrous metals from the rest of the materials.

2. Hand Sorting: Identifying High-Value Metals

While magnets are great for separating ferrous metals, further sorting is often done by hand to identify different non-ferrous metals like copper, aluminium, and brass. Hand sorting requires experience and knowledge of the properties of various metals.

Experienced workers can identify metals by:

  • Colour and Appearance: Copper has a reddish colour, while aluminium is silvery and lightweight. Brass often has a yellowish hue, resembling gold.
  • Weight: Different metals have distinct weights. Aluminium is lighter than most metals, while lead and copper are much denser.
  • Texture and Malleability: Copper is soft and malleable, while stainless steel is tough and resistant to scratching.

Hand sorting helps ensure that high-value metals like copper are set aside from less valuable materials, maximizing profits for the scrap metal collection company.

3. Shredding and Fragmentation: Preparing for Further Sorting

Once the scrap metal is separated into broad categories, it often undergoes shredding. Shredding reduces the size of large metal objects like appliances, cars, and industrial equipment into smaller, more manageable pieces. This step not only makes further sorting easier but also increases the efficiency of the recycling process.

After shredding, metals are often sorted into fragments by weight and size using air classifiers and density separators.

  • Air Classification: This technique blows lighter materials like aluminium away from heavier metals such as steel. It’s particularly useful for separating metals that have similar appearances but different densities.
  • Density Separation: By using flotation tanks or eddy current separators, metal fragments are further sorted by density. Non-ferrous metals, like aluminum and copper, can be separated based on their different responses to magnetic fields and flotation in water.

4. Eddy Current Separation: Isolating Non-Ferrous Metals

For non-ferrous metals, eddy current separation is a highly effective technique used in scrap yards. This process uses a powerful magnetic field that creates an electric current (eddy current) in the non-ferrous metals. This current generates a magnetic field that repels the metal, causing it to be pushed away from other materials.

Eddy current separators are ideal for isolating materials like:

  • Aluminium
  • Copper
  • Brass

These materials are often used in a variety of applications, and by using this technique, a scrap metal company can efficiently extract and process them for resale.

5. Sink-Float Separation: Using Liquids to Separate Metals

Another technique used by some scrap metal collection companies is the sink-float method, which uses liquids to separate metals by density. In this process, metals are placed in a tank of liquid, usually water or a denser medium, and allowed to sink or float based on their density.

  • Heavier metals like steel and copper will sink, while lighter metals, like aluminium, will float.
  • This method helps efficiently separate metals of different weights.

The sink-float method is particularly effective in separating metals from non-metallic materials, which may also be present in scrap, such as plastic or rubber.

6. Chemical Analysis and Spectrometry

For more precise sorting, some scrap metal companies use chemical analysis tools or spectrometers to identify the exact type of metal. This is often used when high-value metals are involved, or when distinguishing between metals that look similar.

  • X-ray fluorescence (XRF) analysers: These devices shoot X-rays at the metal and analyse the light emitted from the material to determine its exact composition.
  • Laser-induced breakdown spectroscopy (LIBS): This is a fast, accurate method that can instantly identify the metal type, including trace elements in alloys.

Using these technologies allows the company to classify metals accurately, ensuring they are sorted into the appropriate categories for resale and processing.

7. Shearing and Baling: Preparing Metals for Recycling

Once metals are sorted, they are often processed further to prepare them for recycling. This can include shearing, where metals are cut into smaller, manageable sizes, and baling, where metals are compressed into dense blocks or bales for easier transportation and storage.

For example:

  • Steel and aluminium are commonly baled after being sorted.
  • Copper may be left in smaller fragments for direct resale or recycling.

This preparation step is essential for the efficient transportation of scrap metal to smelters or recycling facilities.

Scrap metal collection companies use a combination of technologies and techniques to separate metals effectively, ensuring that each type of metal is recycled in the most efficient way possible. From magnetic and manual sorting to advanced techniques like eddy current separation and spectrometry, each process plays a vital role in maximizing the value of collected scrap metal while minimizing environmental waste. Proper separation not only increases profitability but also contributes to a more sustainable and environmentally friendly recycling industry.

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