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XRF Vs. LIBS: Which is Best for Sorting Scrap Metal?

By Adam Ioannidis

We touched on the evolution of scrap metal sorting technology in one of our last articles, but today we thought we’d concentrate on two specific technologies that are quite prevalent in the industry – XRF and LIBS. These two sorting technologies both have their advantages and disadvantages and our Melbourne-based metal recycling experts are going to be breaking those down for you in this explorative article.

The fundamentals of XRF

XRF (X-ray fluorescence) has been utilised in the metal recycling industry for over two decades and is a tried and true process that has revolutionised the sorting process. The radiation from the X-ray determines a metal and alloy’s content and composition. How does it do this? When the radiation bombards a material (metal, in this instance), fluorescent, otherwise known as secondary, X-rays are emitted. The XRF scanner interprets these emissions and uses it to define the composition of the metal and ultimately conclude what type of metal it is. This is considered a non-destructive sorting method as the metal’s physical shape is not compromised.

Advantages of XRF

XRF identifying machines are available in both handheld and larger, automated options which are great for quickly sorting through a large number of pieces. XRF is capable of distinguishing between different grades of alloys. So, if you have several different stainless-steel grades in a container, an XRF scanner will identify each one specifically – making for an efficient and quick scrap metal sorting process. In addition to distinguishing between grades of stainless steel and aluminium, glass can also be separated at incredible speeds in an automated XRF machine.

Disadvantages of XRF

One of the biggest concerns with XRF scanning technology is that at the end of the day, it is still using radiation to achieve a result – and even though it is low-level radiation that isn’t harmful to humans, there is still some concern over it. The radiation also requires extra PPE to be purchased and worn as well as licensing and regulatory paperwork to be completed. Some of the older handheld XRF scanners are also unable to identify light elements such as carbon or lithium. This is due to the fact that the energy released is so low that it is usually is either reabsorbed into the metal or blocked by the air – preventing the scanner from receiving a sufficient sample.

The fundamentals of LIBS

On the other end, we have LIBS (laser-induced breakdown spectroscopy), which is a newer technology and doesn’t utilise radiation to achieve a result. Instead, it uses a high-focus laser that essentially erodes the surface of the metal. As this occurs, the atoms decay and emit light wavelengths. These wavelengths are actually specific for each element – thus, the type of metal can be determined. LIBS is a minimally destructive method since it does melt a portion of the surface in order to obtain a result.

Advantages of LIBS

LIBS can identify types of metal rapidly as well as perform simultaneous multielement analyses. Unlike XRF, there is no need for extra PPE equipment or licensing because there is no radiation present when using LIBS scanners – which also eliminates the concern of exposure. LIBS scanners used to be much more effective at analysing light metals compared to XRF – however, more modern XRF scanners have improved on this shortcoming. Aluminium is also considered to be easier to sort with LIBS technology.

Disadvantages of LIBS

An expert on metal analysis, John I.H. Patterson, PhD., and consultant for Bruker – a company that manufactures scientific instruments – stated in 2015 that XRF is the preferred method when factors such as accuracy and precision matter, implying that LIBS falls short in these categories. Additionally, LIBS is not as effective when it comes to heavy metals, high-temperature alloys and stainless steel sorting

Interested in recycling metal in Melbourne?

At Metal Men Recycling, we use the latest technology and methods to ensure your scrap metal is sorted as effectively and efficiently as possible. Doing this guarantees that the recycled product is as pure as possible and fit for repurposing in a variety of industries. If you’ve got some spare scrap metal lying around, then bring it over to Metal Men recycling – the home of metal recycling in Melbourne.

We can buy several types of metals. And, if your business is looking to unload a hefty amount of metal, then ask us about our pickup and drop-off bin service that will streamline the process for you. Whatever your need – Metal Men Recycling can cater to it.

So, what are you waiting for? Contact us today by calling 03 5941 6677 or filling out our online form.

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