First cleaning, then analyzing
Laser spectroscopy recognizes the substances by their unique optical spectrum. The method uses this “fingerprint of light” to precisely analyze the alloy composition of metal scrap at high conveying speeds in the mass flow. It is therefore essential to clean the measuring range beforehand and remove coatings. With this laser ablation, a high-performance laser first cleans a small area on the surface of a piece of scrap in one to two hundredths of a second, even several times in succession. In the second sub-process, a laser-induced plasma spectroscopy (LIBS) is performed on the previously cleaned surface with the same laser.
A spectral analysis determines the chemical composition of the examined scrap piece. With this data, the metal can be sorted according to the actual alloy requirement of a target melt. Sorting is carried out by air pulse technology with up to 30 scrap pieces per second. Thanks to the support of the “Deutsche Bundesstiftung Umwelt” (German Federal Environmental Foundation), the prototype was realized, tested and further developed under operating conditions.