Reduce Analysis Time: Sample Preparation for OES, XRF and XRD

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The Importance of Sample Preparation

Numerous factors influence the quality of measurement results, including grain size effects, matrix effects, and sample surface characteristics. That is why we assist in selecting the optimal parameters for your application, ensuring accurate results. We offer customers the opportunity to test samples and materials in our application laboratories alongside our specialists.

Preparation of Metal Samples vs. Powder Materials

Your material characteristics determine the application of sample preparation processes and analysis instrument. Due to its quick analysis times and precise measurement outcomes, Optical emissions spectroscopy (OES) stands out as the preferred method for analyzing materials in steelworks, foundries and aluminium plants. The milling process is primarily used due to its fast processing and to minimize inhomogeneity of metal samples and solid bodies. In selected cases, the grinding process is also used. Crushing, Grinding and Pressing offer a time and cost-effective approach to sample preparation, widely utilized in analyzing various inorganic and organic materials. Powdered samples not only enable determination of chemical composition by X-ray fluorescence analysis (XRF), which is also used for slag analysis in steelworks, but also facilitate the application of X-ray diffraction techniques, such as those used in cement plants to ascertain mineral content. Ensuring the sample surface under analysis is both representative and homogeneous is of utmost importance. QCS assist you in selecting the right sample preparation processes for your application.

Sample preparation of powder materials (cement, clinker, slag)

Metal Sample Preparation - The Significance of Removing Parts from Surface

Ensuring the representative and homogeneous nature of the sample surface is paramount for accurate analysis. This is especially crucial for production control samples in steelworks, foundries and aluminium plants. and other manufacturing sites. Several factors contribute to the need for this precision.

Metal Sample Preparation by Milling

The reason why milling is the most appropriate solution is that QCS integrates components meticulously tailored to each other. The clamping unit, metal milling heads, spindle motor, and traversing axes are engineered to deliver ample torque, enabling seamless processing of even tough samples. This design minimizes vibrations and oscillations, preventing any interference with the flatness of the analysis surface, ensuring pristine results. Additionally, meticulous fine-tuning of components extends the lifespan of consumable materials, notably cutting plates. QCS is committed to offering personalized advice on selecting the most suitable milling machine, clamping fixture, milling head, and cutting plates tailored to your unique application and sample shape. We provide assistance in determining the optimal milling parameters for your specific needs.

Example on Steel Samples

Firstly, upon separation from the sampler mold, a thin layer of scale (approx. 10µm) forms on the sample surface due to brief exposure to ambient air. Additionally, the sample often contains segregations—inhomogeneities resulting from the separation of solutes during solidification of the liquid steel. These separations persist even after complete solidification, contributing to lasting variations in chemical composition. Moreover, the outermost layer of the casting tends to be oversaturated with elements like carbon, phosphorus, sulphur, and boron, further necessitating the removal of approximately 0.3 -0.6 mm of the sample surface to access undisturbed layers for analysis.

This example shows the significance of removing part from steel sample surface and is also the case with aluminum and pig iron in a different way of chemical composition of the sample itself. Typically the milling process is applied here.

Metal Sample Preparation by Grinding

In certain scenarios, grinding presents an alternative for surface preparation, particularly for exceptionally hard materials. Employing fixed grinding particles with a coarse grain is recommended to ensure a rapid and consistent removal rate, minimizing processing time while maximizing surface flatness. Occasionally, additional fine-grinding may be required following surface grinding to refine the material further. Grinding media composed of alternative composites are utilized for this purpose, effectively reducing any residual deformations on the sample surface. QCS is available to offer guidance in selecting the optimal grinding process and suitable grinding materials tailored to your requirements.

Powder Material Preparation - The Significance of Preventing Material Contamination and Inhomogeneity

Since only a specific portion of the sample interacts with X-ray during analysis, it’s crucial for XRF and XRD analysis to have a representative and consistent sample surface that can be reproduced. This can be assessed through replication series. Additionally, pressing sample material into metal rings can sometimes lead to unwanted particle separation or arrangement, potentially compromising the analysis results. To prevent material contamination and ensure representativity during sample preparation, several processes such as fine grinding, dosing, and pressing of sample material require efficient and regularly cleaning of the components involved. This is one reason why we recommend our automated machines Depending on specific material needs, we provide various technical solutions like dry cleaning with compressed air, wet cleaning, sand cleaning, and the use of blank samples

Powder Sample Preparation by Crushing

Our crushers are specifically engineered for the rough and preliminary crushing of sample materials like clinker or slags. Typically the next process step is grinding due to attaining the precise fineness needed for subsequent spectroscopic analysis by using a disk vibration mill.

Powder Sample Preparation by Grinding

Before pressing, it’s essential to finely grind the material to ensure proper homogeneity. QCS provides a range of disk vibration mills with various configurations. Even extremely hard materials like silicon carbide can be ground to a fine grain size, ensuring high-quality analysis. The achievable fineness depends on factors such as the material itself, input quantity, grinding aids utilized, and initial grain size. Throughout the grinding process, abrasion naturally occurs on the grinding stones and within the grinding box. It’s crucial that the grinding tools are appropriately hard and composed of materials that don’t introduce elements of analytical interest. To address this, various grinding boxes are offered to prevent the ingress of elements relevant to the analysis. We provide assistance in determining the optimal grinding parameters for your powder materials.

Powder Sample Preparation by Pressing

Pressing is the final process step of powder sample preparation. The choice of pressing method depends on the analytical needs and the sample material. In automated presses, steel rings are the preferred option as they offer enhanced stability and minimize contamination risks in the spectrometer by preventing sample edge eruptions. Two types of steel rings are available (Ø 40 mm & Ø 51 mm). However, for free pressing, pressing of 2 components, and pressing in aluminum trays, the diameter of the pressing tool can be selected with certain limitations. Employing steel rings provides significant benefits compared to other pressing techniques, especially in automated sample preparation systems. Steel rings effectively minimize the risk of contamination in the spectrometer by preventing sample edge eruptions. QCS is available to offer guidance in selecting the optimal pressing tools for your application.

Sample Preparation Manual vs. Automation: Maximizing Efficiency

We offer manual, semi-automatic or fully automatic solutions for all process steps in sample preparation. However, if you aim to enhance efficiency without escalating expenses due to manual mistakes or longer operating time, our automation solutions is the answer. Here’s how automation can be beneficial:

Enhance analysis reliability by minimizing human intervention, ensuring consistency and precision.
Eliminate manual operator variations and subjective influences on results.
Increase productivity, diminish response times, and expand production capacity.
Expedite sample processing to manage larger volumes effectively.

Increase efficiency with sample analysis expenses by using your team for higher-value tasks. Our automation solutions are userfriendly products equipped with extensive functionality and operational adaptability. You can customize parameters of our systems effortlessly before, during, and after installation to address evolving needs

Laboratory Automation of Metal Samples analyzed by OES.

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