Scrap metal recyclers rely on the latest technologies to perform accurate sorting. The exact chemical composition of scrap, including the existence of contaminants or hazardous elements, must be determined to help ensure the quality supplied to buyers, the integrity of the business, the safety of employees, for regulatory compliance, and for profitability.
In addition, we’ve outlined below the seven best practices for getting accurate readings when analyzing and sorting your metals (which you would have heard our experts present if there was a booth to visit).
- Grind it Clean. Watch for coatings, platings and residual paint. There is much Ni-coated Fe, and the handheld X-ray fluorescence (XRF) analyzer may identify this pure Ni if the coating is not removed. Paint also interferes with chemistry and can cause an alloy to be misidentified. Natural occurrences can also interfere with accurate readings of metals especially those sitting out in the elements – be sure to remove corrosion, oxide layers (rust), and scale. And of course, interfering materials (like caulk, rubber, etc.) should also be removed.
- Take Layers of Metal Apart. Analyze each layer separately as there could be entrapped lead, or copper-bearing electronics inside.
- Grind It to A Powder. The amounts of recoverable Platinum (Pt), Palladium (Pd), and Rhodium (Rh) in each catalytic converter can range from 1-2 grams for a small car to 12-15 grams for a big truck in the US. To avoid considerable financial losses, there is a definite advantage in having the ability to determine quickly and accurately the contents of Pt, Pd, and Rh in spent catalytic converters at the collector’s site or in the refineries.
- Take Longer Measurements to Distinguish Between Close Alloys. Alloys with very close specifications may both be displayed as a close match. A longer reading (5 – 10s) may provide the precision necessary to separate in some cases.
- Be Careful of The Fragile XRF Window. Small turnings have been one of the most frustrating items for many handheld analyzer users as the sharp edges have broken many fragile XRF windows resulting in costly repair bills. Powders can cling to the measuring window and add to subsequent readings. Even welding fumes can settle out on the window and add false metal concentration readings.
- Take Radiation Safety Training. The analyzer emits a directed radiation beam when the tube is energized (tube-based instrument) or when the shutter is open (isotope-based instrument). Reasonable effort should be made to maintain exposures to radiation as far below dose limits as is practical. While the radiation emitted from a portable XRF analyzer is similar to the exposure received in a normal medical or dental X-ray, care must be taken to always point a handheld XRF analyzer directly at the sample and never at a person or a body part. (See XRF Safety training.)
This last best practice does not involve handheld XRF analyzers but should be followed by Metal Recycling facilities.
- Keep Your Facility and Your Products Safe from Radiation. Undesirable radioactive sources (from old medical equipment, density gauges, etc.) 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.
We have provided more details in our free ebook: A practical guide to improving metal and alloy sorting for scrap metal recyclers. In addition to best practices, it includes featured products used in the industry and easy-to-understand explanations of the technologies involved in metal and alloy analysis. It even gives suggestions as to what to look for in a handheld XRF analyzer.
- Download our free ebook: A practical guide to improving metal and alloy sorting for scrap metal recyclers
- XRF Safety training