With the focus shifting onto the purity of materials in the Chinese recycling industry, it’s crucial you have the right equipment to ensure a reliable sorting process. XiangDong Ren, Business Development Manager at Hitachi High-Tech, weighs up the options.
As the government works towards a cleaner environment, it has introduced measures that aim to reduce pollution. This includes strict new limits on materials entering the country for recycling. In most cases, the contaminant or carried waste level has been set at just 0.5%, though for non-ferrous metals the regulation is slightly more generous at 1%.
With the government focusing so closely on recycling and introducing stricter impurity thresholds, businesses that sort materials for recycling are looking for ways to improve their systems. For over 45 years, Hitachi High-Tech has been developing technologies that efficiently and accurately identify metal and non-metal substances.
LIBS, XRF or OES
When it comes to sorting materials, there are three types of technology to consider. The first is LIBS, short for ‘laser induced breakdown spectroscopy’. LIBS analysers, like the Vulcan, use a laser to excite the molecules on the surface of the sample and the type of light that is emitted helps determine its chemical makeup.
Then there is XRF – ‘X-ray fluorescence’. Hitachi High-Tech’s X-MET8000 products are also handheld devices, but rather than a laser they use a low intensity X-ray to energise the surface of the sample. Again, the light that is reflected back is analysed to determine the elements within the sample.
Finally, with OES (optical emission spectroscopy) the surface of the sample is excited using an electric spark. The colours of the light emitted by the ions in the sample are detected by the spectrometer, which gives a reading saying what the substance is. Several OES instruments are available from Hitachi High-Tech, including the portable PMI-Master Smart.
This is a very simple description of the three technologies, and each of them is suited to identifying a particular range of elements. The solution you choose will very much depend on what your main requirements are.
To help you decide, we’ve put together a quick guide below.
Products in the Vulcan (LIBS) and X-MET8000 (XRF) ranges are handheld analysers that can be easily carried around a scrapyard or recycling facility in order to test samples on the spot. They both have a similar, rugged design, and have been engineered for industrial environments.
The OES-based PMI-Master Smart consists of a 15kg cordless unit that can be moved around the site in order to take measurements.
While all three devices are portable, whether you choose the Vulcan (LIBS), the X-MET8000 (XRF) or the PMI-Master Smart (OES) will depend on what kind analysis you need to carry out.
If your facility needs to identify different types of plastic, powders, ceramics, rubbers, wood and so on, the handheld X-MET8000 is the right instrument for you. Because X-ray fluorescence is so versatile, it can be used to analyse metal alloys, as well as most other types of solid material. The instrument’s fundamental parameter method makes it suitable for a wide range of metal and non-metal samples.
The fundamental parameter method also makes the X-MET8000 handheld analyser the ideal choice for users who need to detect a wide variety of uncommon alloys. A grade list of over 1,600 alloys comes pre-installed, and customised lists can also be developed.
It is in the area of identifying substances composed of the light elements (Li, Be, B, C, N, Na, Mg, Al, Si, P and S) that choosing the right instrument becomes trickiest. If identifying samples containing carbon, nitrogen, boron or sodium (C, N, B, Na) is a common task for you, then the PMI-Master Smart is the only suitable device because OES technology gives the clearest readings for these elements.
For aluminium (Al) the Vulcan Expert (using LIBS technology) is the best choice as this handheld has been calibrated for the task. However, the X-MET8000 (XRF) and the PMI Master Smart (OES) are also capable of identifying aluminium, so your choice may be based on the level of accuracy you require, the volume of aluminium sampling you undertake, and your other analysis needs.
If you need to measure sulphur (S) and phosphorus (P) in steel, the X-MET8000 Expert handheld analyser most suited to the job. However, a PMI-Master Smart with UVTouch probe can also carry out the task.
To measure tool steels and low alloy steels accurately, OES is the best technology to use, which means that the PMI-Master Smart is the optimum instrument choice. In many cases the X-MET8000 (XRF) will provide very good results, and the Vulcan (LIBS) can also help companies that need to some of these alloy groups, but OES provides the lowest detection limits and therefore offers the most accurate results.