How the right sample preparation and automation support reliable critical minerals analysis

In the face of declining ore grades and increasingly remote mining locations, efficient processing is more important than ever to safeguard profit in critical minerals operations.

Accurate and timely analytical data at every stage of the workflow can help. Many leading mining companies are combining elemental and mineralogical analysis with X-ray fluorescence (XRF) and X-ray diffraction (XRD) to gain insight into their processes.

However, the effectiveness of these methods depends heavily on sample preparation, calibration, and how analytical results are generated and applied across your operations.

In the fourth episode of the Critical Minerals Expert webinar series, Malvern Panalytical experts Uwe König, Neil Eatherington, and Qiaona Zhang discuss how you can standardize this process.

Read our recap to find out how sample preparation, automation, and integrated XRF and XRD workflows contribute to reliable analytical outcomes for critical minerals producers.

Key takeaways

• Sample preparation has a significant influence on analytical accuracy, precision, and reproducibility.
• Different stages of the mining process require different preparation methods, depending on speed, cost, and accuracy requirements.
• Combining XRF and XRD provides a more complete understanding of both elemental composition and mineralogy.
• Automation is becoming increasingly important as mining operations move to more remote locations and require continuous analytical control.

The role of sample preparation in analytical quality

In the webinar, Qiaona highlighted that a large proportion of analytical error can originate during sample preparation. Even when using advanced X-ray instrumentation, inconsistent or unsuitable preparation methods can lead to poor precision and unreliable results.

For critical minerals, where ore grades are lower and mineralogical variability is higher, consistent preparation methods are essential. Well-prepared samples support reproducible measurements and improve confidence in the data used for operational decisions. This starts with selecting the right sample preparation method.

How to select preparation methods for different process stages

The appropriate sample preparation method depends on many factors, including:

• Sample type
• Required turnaround time
• Sample variability
• Accuracy targets in that section of the mining and processing workflow

For example, loose powders and pressed pellets are commonly used for process monitoring and grade control. These methods are fast, relatively low-cost, and suitable for high-throughput analysis. However, they are also more sensitive to mineralogical and matrix effects.

Powders and pellets are therefore best used in high-throughput environments where speed is critical and accuracy targets are slightly lower – for example, when performing rapid elemental QC.

Fused bead sampling, on the other hand, requires more preparation time and incurs higher operating costs. Fusion reduces matrix effects and delivers highly accurate results, and is therefore typically used for final products, concentrates, and high-accuracy quality control.

Our experts noted that chemical and physical reactions during preparation, such as sulfur loss during the fusion of sulfide materials, must also be taken into account to avoid biased results.

Strengthening the calibration link in your analytical chain

Rather than viewing analysis as a single measurement step, Quiona described the analytical chain as a sequence of connected processes. This chain includes not only sample preparation, but also calibration, measurement, data processing, and reporting. Each step in the analytical chain contributes to the reliability of the final data.

The calibration step is particularly important for XRF analysis, which relies on appropriate calibration standards.

Neil explained that, for critical minerals, suitable certified reference materials are not always readily available, which increases the importance of customized or synthetic standards.

One example is Malvern Panalytical’s WROXI Certified Reference Materials (CRM), a high-quality synthetic calibration standards kit that covers a wide range of oxide materials such as ores, rocks, and geological materials.

Malvern Panalytical also has extensive experience producing bespoke calibration standards.

Automation in critical minerals laboratories

Automation was a central topic of the discussion, particularly in the context of remote mining operations. Automated sample preparation and analysis help reduce human error, improve consistency, and enable continuous analytical control.

Automated systems can support safer working conditions and ensure that analytical data is available without interruption. This is particularly important for mining operations that rely on real-time or near-real-time data to maintain stable processing conditions.

Integrating XRF and XRD analysis

The session also emphasized the value of combining elemental and mineralogical analysis. Elemental concentrations provide information on grade, while mineralogical data determines how materials behave during processing.

For example, Uwe explained that copper ores may require different processing routes depending on whether copper is present as oxides or sulfides. Similar considerations apply to rare earth elements, where mineralogical form strongly influences extraction methods. This is why mineralogical analysis is at the heart of effective critical minerals mining.

Integrated workflows that analyze the same prepared sample using both XRF and XRD allow mining companies to obtain complementary data without adding complexity to laboratory operations.

Support faster deployment with turnkey solutions

To simplify implementation, Malvern Panalytical offers expert analytical kits that combine calibration standards, preparation methods, and validated application templates. These solutions are designed to reduce method development time and support consistent analytical performance across multiple sites.

By standardizing preparation and calibration approaches, laboratories can achieve reliable results more quickly, even when working with complex or variable critical mineral materials.

Reinforce your analytical chain. Meet future analytical demands.

As the critical minerals sector continues to evolve, analytical workflows must adapt to increasing complexity and operational constraints. Consistent sample preparation, appropriate calibration strategies, and integrated XRF and XRD analysis play a central role in maintaining data quality.

By addressing the entire analytical chain and supporting automation where appropriate, mining companies can improve confidence in their analytical data and make more informed processing decisions as demand for critical minerals continues to rise.

Do you have any questions about the topics discussed during this webinar? Please contact one of our experts.