The analysis of aluminum scrap is a challenge compared to the analysis of other materials, such as stainless steel. The importance of proper analysis lies in controlling the quality of the final product and identifying any hazardous materials, such as lithium, for subsequent casting.
For the analysis of alloys in recycling facilities, OES, HHXRF and the more recent LIBS technologies are used. Each of them has its advantages and limitations. No technology alone can satisfy all the requirements of the aluminum recycling industry. OES and HHXRF are mature technologies with known performance. LIBS technology is new and promising and can already replace HHXRF instruments in a number of applications, while it has the potential to spread to other applications where OES and HHXRF cannot meet the requirements.
When selecting the appropriate technology, the requirements of the recycling plant must be considered. Specifically, the following questions must be asked:
- What data should be analyzed and to what level?
- What is the volume of scrap?
- How important is analysis speed?
- Is the use of X-rays a problem?
XRF Technology
Traditionally, aluminum scrap was separated using handheld X-ray spectroscopy (HHXRF). These spectrometers are fast, accurate, portable, and capable of detecting a wide range of elements and concentrations, making them ideal for metal recycling plants and aluminum smelters. However, this technology cannot detect some components such as magnesium and carbon, which require a longer time to identify.
OES Technology
The most accurate technology on the market for the analysis of light metals and the identification of unwanted elements is OES, which is however limited by the inability to move the instruments that operate on it. For this reason, OES instruments operate in laboratories. In addition, OES technology requires very good cleaning of the surface of the alloy to be analyzed.
LIBS technology
LIBS technology is the latest development in scrap metal identification and separation technologies. LIBS technology analyzers are faster than XRF, giving results within 1 second. In addition, they excel in identifying light elements such as aluminum, magnesium and silicon. LIBS technology can be used without a license requirement, unlike HHXRF analyzers. However, in LIBS technology, the instruments are calibrated empirically using certified reference samples. This poses certain limitations compared to HHXRF spectrometers which use fundamental calibration parameters and can analyze up to 35 samples simultaneously over the full range of 0-100%. This limitation is important for applications requiring the analysis of concentrations lower than 0.05%.
Choosing the right technology
| I WANT TO… | |||
|---|---|---|---|
| I want to… | LIBS | HHXRF | OES |
| I have a small, light and portable analyzer | *** | *** | * |
| Accurate analysis of the chemical composition of the aluminum alloy | * | ** | *** |
| Analysis of unknown and trace elements below the level of <0.1% | – | ** | *** |
| Sample analysis with minimal surface preparation | ** | *** | * |
| Ability to transfer analyzer to the sample | *** | *** | * |
| I have minimal risks, certifications and licenses | *** | * | *** |
| Rapid separation of aluminum alloys | *** | ** | * |
| Lithium Detection in Aluminum Alloys | *** | – | – |
Oxford Instruments offers all types of existing technologies that can meet the demands of the recycling industry.
See the full range of analytical equipment we provide here .
