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X-Ray Diagnostics for Scrap Metal Sorting

UHV Technologies

Low-Cost High Throughput In-Line X-Ray Fluorescence Scrap Metal Sorter

ARPA-E Award: 
Lexington, KY
Project Term: 
01/01/2014 to 04/30/2019
Project Status: 
Technical Categories: 
Critical Need: 

Recycling light metals such as aluminum, titanium, and magnesium from scrap is primarily done manually, making it an inefficient and expensive process. Existing automated technologies are unable to distinguish different types of alloys. Innovation in light metal recycling is crucial because light metals can be used to reduce the weight of cars and aircraft, which could significantly reduce both energy use and carbon dioxide (CO2) emissions from transportation. Cost-effective scrap recycling could dramatically reduce the cost of light-weight metals, such as those used for aircraft construction and vehicle light-weighting.

Project Innovation + Advantages: 

UHV is developing a sorting technology that uses X-rays to distinguish between high-value metal alloys found in scrap of many shapes and sizes. Existing identification technologies rely on manual sorting of light metals, which can be inaccurate and slow. UHV's system will rapidly sort scrap metal passed over a conveyer belt, making it possible to lower metals waste while simultaneously increasing the quality of recycled metal alloys. By analyzing the light emitted from X-rayed metal pieces, UHV's probe is able to identify alloy compositions for automated sorting. By automating this process, UHV would significantly reduce the costs associated with recycling light metal scrap.

Potential Impact: 

If successful, UHV's sorting diagnostics would reduce energy consumption and costs associated with manufacturing light metal components from recycled light metal scrap that is typically discarded.


Light-weighting vehicles to improve fuel efficiency could reduce U.S. dependence on foreign fossil fuel resources used in the transportation industry.


Recycling high-grade aluminum, magnesium, and their alloys from scrap metals reduces the amount of metal disposed in landfills.


Light metal recycling would enable a low-cost alternative to primary metal extraction, making light metal consumer applications more affordable. Recycled metals produced under this process would also be higher value due to more accurate scrap sorting.

Innovation Update: 

(As of August 2016)
In May 2016, UHV installed its first test sorting line with a potential throughput of 40 million pounds per year at industrial partner OmniSource’s scrap processing yard. UHV's pilot installation has been used to test the system's throughput and reliability under actual industrial conditions. The pilot phase for this work will conclude in 2016, and negotiations for a scale up to full industrial installation are ongoing.

To develop their metal alloy sorter, UHV first created a linear X-ray tube that uniformly illuminates the entire width of a conveyor belt while reducing tube power requirements by 10, cutting costs and enhancing reliability and lifetime. The system was constructed using multiple arrays of commercial silicon avalanche photodiodes, paired with proprietary X-ray optics to record spatially resolved X-ray fluorescence spectra. The UHV team developed software to match each piece of metal passing underneath the X-ray system with a fluorescence fingerprint. This software is the first of its kind, able to analyze and then use standard spectra to identify and send instructions to the sorting hardware for correct alloy shunting in just milliseconds. The software also calculates the percentage and weight of each element in each batch of sorted scrap ready for melting during recycling. This eliminates the need and cost of the extra melting step that exists in current recycling processes. The system has demonstrated the ability to discriminate and quantify the concentrations of ten elements with accuracies greater than 99%.

For a detailed assessment of the UHV team's project and impact, please click here.

ARPA-E Program Director: 
Dr. David Tew
Project Contact: 
Dr. Nalin Kumar
Phinix, LLC
Release Date: