Meatballs from Ferrous Scrap

Precise sensor-based copper meatballs removal solution capable of separating copper meatballs from ferrous scrap with XRF (X-ray) sensor and electromagnetic (EM) sensor

Ferrous Scrap

Fractions of steel manufactured from ferrous scrap are starting to contain an increasing amount of residual copper. Currently, about 40 % of the worldwide steel production is made from recycled ferrous scrap – and this is increasing all the time.

The biggest challenge in iron recovery is the purity. If the volume of copper content in recycling ferrous scrap is too high, quality in the final product will go down. Only steel scrap that meets the required specifications (e. g. type E40 with less than 0.25 % copper content) may enter the steel production process for high quality products as secondary resource.

Residual copper found in this ferrous scrap is a metallurgical and processing poison, leading to problems when processing scrap metals. When too much copper is found in the steel-making process, the produced steel batch to become brittle or too soft, affecting the overall quality of the steel that is produced.

This rise in the volume of residual copper found in steel-making has been a major concern to everyone from scrap processing plants to steel mills. To fix this problem, recycling facilities are doing everything they can to remove what they see as the main contributor to this increased copper volume, by removing ‘meatballs’ from ferrous scrap.

Copper Meatballs

Copper meatballs are electric motors - usually found in End of Life Vehicles and electrical white goods - which consist of a steel shell, copper wires, and free copper. As they are very often attracted by the magnetic separation in a recycling process, they are often found in ferrous scrap.

These copper meatballs pollute the ferrous scrap, and if they are found in shredded ferrous scrap, the steel content found within the meatballs reduces the market value of the scrap metal.

Copper meatballs, if caught in ferrous scrap sorting, can be responsible for damaging non-ferrous waste separation equipment further on in the separation process, and start fires in waste residue as they retain heat from the shredding process.

Due to the mechanical problems and the lost revenue that copper meatballs can bring, recycling facilities and waste separation plants have been trying to find a new, automated method to remove them from the non-ferrous scrap. At the same time, the automated removal can help to maintain a consistent production of high-quality steel scrap with copper levels at less than 0.20%

TITECH Technology

In order to remove copper meatballs from ferrous scrap, TITECH uses a new XRF (X-ray fluorescence) sensor. This sensor works by directing X-rays onto the surface of the objects in the ferrous stream. For the first time, XRF allows the detection of existing elements in the objects scanned. The material will be excited by low-energy X-ray radiation and element specific fluorescence will be released. With an energy dispersive X-ray sensor this fluorescence can be measured. The data will be processed and information about the presence of elements and their concentration are the result.

Using XRF technology in TITECH machines tells us that copper is in the stream, but not the size and precise location of the copper. This information is combined with additional data from an electromagnetic sensor which uses SUPPIXX® to identify the position and size of the object – and a set of valves eject it precisely.

The innovative combination of using both XRF and an electromagnetic sensor means TITECH can accurately locate copper meatballs in a stream.  This clever combination of XRF and electromagnetic sensors is an industry first, and makes the TITECH x-tract the most accurate machine of its kind.

TITECH’s x-tract [XRF] is a result of 2 years of research into meatball sorting, meatball extraction and the separation of copper meatballs from ferrous scrap streams. The x-tract [XRF] has been comprehensively tested since it was installed at a client’s recycling facility in November 2010. In co-operation with a steel smelter, intensive tests were carried out, analysing quality of copper content after separation, machine stability, and much much more.

The System Design

TITECH sorting systems can be smoothly integrated into your plant. The flow chart above shows at which stage of the sorting process you can use TITECH technology, and how it can be utilised. First, input material, i. e. used cars and other ferrous scrap, is shredded in the shredder. A magnet then generates a fraction of iron or steel and other magnetic materials. A subsequent protective screening prevents larger particles from getting into the sorting system. The TITECH x-tract [XRF] then detects the impurities with a high degree of precision, and ejects them. In this process, other resources such as copper can be gained. The process results in a high-value steel fraction of uniform high purity which is suitable for producing new steel.

The solution

Due to its X-ray fluorescence sensor, the TITECH x-tract [XRF] can detect copper meatballs and other impurities by their atomic characteristics and eject them. In doing so, it detects the material particles so precisely that it only ejects a minimum quantity of the target material with the copper. This means: High purity in connection with minimum material loss. Each material leaves an atomic fingerprint when being exposed to x-rays: The TITECH x-tract [XRF] measures this atomic fingerprint and can thus unambiguously identify the copper coils (meatballs) – and other impurities – and remove them from the input material.

The advantages

• Reliably stable steel quality (e. g. specification E40: Cu < 0.25 %)
• Increased value of the steel product, additional profits of 3–6 % can be expected.
• Reduced labour costs (manual sorting).
• Extremely fast payoff
• Highest selectivity
• Very robust and proven design
• Highest safety standard
• Good adaptability to customer requirements
• Become preferred supplier due to high purity
• Emergency service hotline.