Define what sorting must achieve
Recycled feedstock varies widely. One load can contain different alloy grades, coatings, solders and attached material. XRF provides elemental composition to support sorting; an instrument’s grade suggestion generally comes from matching measurements against a grade library. The business still needs to define the elements controlled by the purchase contract, allowable mixed materials and acceptance criteria. Identifying a name does not establish the quality of an entire load.
Relate the measurement surface to the material
Inspect the measurement area for coatings, oil, oxide and welds, and choose a location representative of the intended material. Any necessary surface preparation should follow a work instruction that avoids contamination from abrasive tools. For curved surfaces, small parts and multilayer structures, confirm that the measurement geometry is suitable. If locations on one item disagree, investigate its structure or heterogeneity rather than selecting the result closest to expectations.
Obtain additional evidence at grade boundaries
Conventional handheld XRF cannot measure carbon, so it cannot resolve every steel-grade distinction based on carbon content. Thermo Fisher’s technical material explicitly discusses this limitation. Acceptance decisions that depend on carbon require an appropriately capable, validated method. When the library finds no match, suggests several similar grades or lacks adequate measurement capability for a critical element, mark the material for confirmation. Retain the composition data and review record instead of choosing a convenient nearby grade.
Preserve the link to the original batch
We recommend linking the incoming batch identifier, supplier, sampling locations, measurement records, sorting containers and confirmation decisions. For batches with critical impurities or a greater risk of mixed material, design additional inspection around the contract and the risk. Checks on receipt, after sorting and before dispatch can help reveal mixing during handling. Inspection coverage needs a reasoned basis; it should not be calculated from an advertised instrument speed.
XRF supplies rapid information for material decisions in recycling. It does not by itself establish uniform composition throughout a batch or verify mechanical properties and heat-treatment condition. Clearly bounded results, tied to identifiable material, make sorting data useful for purchasing, production and delivery.
References
- Thermo Fisher — Portable XRF in the Metal Lifecycle
- Thermo Fisher — XRF or LIBS? Stainless steel analysis
Accessed: September 29, 2026. This article discusses methods and workflows. Apply the practical recommendations in conjunction with applicable standards, contractual requirements and local method validation.