Introduction
Fusion is a well-established method for producing ideal, homogeneous samples for X-ray fluorescence (XRF) analysis. By transforming solid samples into a glass bead, this technique enables precise and reproducible elemental analysis.
Over the past ten years, fusion technology, especially with electric fusion instruments, has developed rapidly. At FLUXANA, this concept has been continuously advanced and validated through numerous applications.
In this presentation, we will present new developments in a broad selection of different fusion applications.
Fusion for Different Sample Types
The procedure will be discussed step by step for the following sample materials:
- Fully oxidic samples: Examples such as cement and minerals, where fusion is a simple and effective method for sample preparation.
- Samples with volatile components: Handling of halogens, sulfates, and other volatile constituents to minimize losses during the fusion process.
- Samples with reduced components: Procedures for samples containing reduced components such as sulfides, carbides, metal powders, and ferroalloys, including additional oxidation steps.
- ICP digestions: Differentiation between fusion methods for XRF and alternative chemical digestion methods used for ICP-MS or ICP-OES.
- Peroxide digestions: Fusion methods used for ICP-MS or ICP-OES and other techniques like Ion Chromatography.
Further Development of Fusion Technology
- To improve the recovery of volatile elements, a furnace design was developed in which the door serves as the furnace base, minimizing heat loss during fusion.
- To achieve greater melt homogeneity, the circular stirring mechanism—the most effective method for homogenizing molten samples—has been further optimized.
- To protect the furnace chamber and heating elements during oxidation reactions, the fusion chamber is separated from the heating chamber by a ceramic tube.
- To prevent contamination of the furnace chamber, an integrated ventilation system was introduced to remove reaction products after each fusion, particularly following oxidation reactions.
- To enable automated fusion, a specially designed ceramic holder was developed that accommodates two crucibles and two moulds simultaneously.
- To compensate for temperature inhomogeneities within the furnace chamber, the samples are rotated slowly during fusion (similar to a microwave oven), while each furnace chamber is equipped with its own independent temperature control system.
Conclusion
Fusion is a precise and reliable method for sample preparation in XRF analysis. Continuous development allows users to benefit from our steadily growing know-how, while significantly reducing the time required for developing new applications.