When the exact chemical composition of scrap is uncertain, quality, safety, and regulatory compliance are at risk. To help ensure the product is made of recycled metals, and maximize profit, scrap metal operations rely on handheld X-ray fluorescence (XRF) and LIBS analyzers for accurate, reliable material identification.
Handheld analyzers used in scrap metal recycling can verify elements of interest in virtually all types of metal alloys, from trace levels to commercially pure metals, and are capable of distinguishing alloy grades that are nearly identical in composition to one another.
- XRF is an acronym for X-ray fluorescence spectroscopy. XRF is a non-destructive analytical technique used to determine the elemental composition of materials. Handheld XRF analyzers work by measuring the fluorescent (or secondary) X-rays emitted from a sample when excited by a primary X-ray source. Each of the elements present in a sample produces a set of characteristic fluorescent X-rays, or “unique fingerprints”. These “fingerprints” are distinct for each element, making handheld XRF analyzers excellent tools for quantitative and qualitative measurements, and identifying metals and alloys.
- LIBS is an acronym for Laser Induced Breakdown Spectroscopy, which is an analytical chemistry technique used for quantitative elemental analysis. LIBS technology uses a tightly focused laser to ablate the surface of a sample to form a plasma. The plasma, which then atomizes and excites the sample, emits light that is transmitted through fiber optics and enters the spectrometer through a slit. The light then interacts with a diffraction grating and splits the light into its component wavelengths. The detector produces a spectrum from the sample which can be analyzed, and the concentration of each element determined. Handheld LIBS analyzers can rapidly and accurately determines carbon content and various other elements in metals and alloys — including quantifying carbon in all iron-based alloys and carbon steels. Scrap metal recyclers should use LIBS when they want to identify low alloy/ carbon steels and L and H grade steels.
Handheld LIBS and XRF are best thought of as complementary technologies. When used together, users can expect to measure a greater range of elements. For example, LIBS can detect lighter elements, such as carbon (C), that handheld XRF is unable to. Handheld XRF is considered non-destructive, while LIBS is minimally destructive. More user maintenance is required for LIBS such as instrument cleaning, sample preparation and daily setup, whereas XRF requires little upkeep and is best summarized as “point and shoot”.
Additional technologies for scrap metal recyclers include radiation detection equipment. Undesirable radioactive sources can frequently show up at metal processing facilities, threatening the safety of employees, products, and resulting in expensive plant decontamination and shut down. Multiple points of inspection are necessary in the workflow to ensure processed materials are free from radioactive sources.
For those who want to become leaders in the scrap industry, these technologies can help increase profitability by eliminating the guesswork through reliable scrap metal analysis — more specifically, by:
- Positively identifying numerous alloys at material transfer points to help achieve product quality
- Identifying tramp and trace elements
- Analyzing nondestructively in seconds, with little or no need for sample preparation
- Increasing the speed of metal processing operations
- Protecting your facility and the public from radiation threats
We have several free resources about metal identification technologies that were showcased at the 2021 virtual ISRI show (the largest convention and exhibition in the recycling industry).. You can download them now.