Conventionally, x-ray fluorescence analyzers have been the main tool used for scrap metal sorting. In recent years, however, laser-induced breakdown spectroscopy (LIBS) technology has been of increasing interest for this application. The innovative portable LIBZ series from SciAps offers a number of benefits for scrap analysis.
Because LIBS uses an eye-safe laser instead of x-rays, safety requirements and regulations are much less stringent. LIBS is capable of studying aluminium alloys, red metals, and most of the materials that scrap processors deal with at a high speed - just a few seconds per analysis. This performance benefit is especially noticeable with lighter elements such as Mg, Al, Si, Be, Ca, B and Li.
Better, Faster Scrap Sorting: Z-100
For metal recycling applications, the Sciaps Z-100 is the ideal tool. The LIBS technology based analyzer is capable of very high speed analysis of low atomic number elements, which are measured either very slowly or cannot be measured at all using handheld XRF. It features excellent speed and analysis for stainless steel, nickel alloys and other high temperature alloys.
On copper and aluminium alloys of mobile OES, the Z-100 offers high performance with comparable portability capability for high temperature alloy to handheld XRF. The weight of the Z-100 is just 4lbs (1.8kg), around the size of a power drill and lighter than mobile OES systems.
The LIBS technique involves aiming a laser at a sample, instantly heating it and creating an electron plasma. The cooling of the plasma after around 1µs results in the electrons returning to the atoms constituting the sample, and in the process emitting light at a range of discrete wavelengths. The wavelengths are resolved by the spectrometer, and the elements present and their concentrations are determined by the processor.
Since LIBS is an optical method, and the light measured is in the NIR, visible and the UV region, it can analyze many more elements compared to portable XRF. Portable XRF is not capable of measuring lower atomic number elements from hydrogen through to sodium. With LIBS, analysis of these lighter elements is possible, and detection limits for Mg, Si and Al are also much lower.
Improved Safety and Robustness
The laser used by SciAps LIBZ is eye-safe, and there are no radiation risks. The laser is approved under Class 1M - the same as a laser pointer. This greatly reduces the health and safety risks in operation compared to x-ray based devices, as well as reducing the time spent on regulatory compliance and operator training.
Operators can hold turnings or other small sample pieces directly in front of the analyzer by hand - this removes the need for additional equipment such as shielding or sample holders, and improves productivity.
The LIBZ analyzers have a thick quartz window behind the front aperture, which cannot be penetrated by turnings or scraps. This removes the risk of detector damage which exists when analyzing this type of sample with XRF, and does not affect the transmission of light to the spectrometer at the rear of the unit.
Laser-induced breakdown spectroscopy has been used extensively for over two decades as a laboratory and benchtop technique. SciAps has been successful in miniaturizing LIBS technology, using its years of experience, technical expertise and commitment to serving its customers. The resulting instrument, the Z-100, is a compact, robust, and convenient analyzer with several benefits over the existing dominant technologies for scrap metal analysis and sorting.
This information has been sourced, reviewed and adapted from materials provided by SciAps, Inc.
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