XRF Sample Preparation

Pressed Pellets for XRF Analysis

A pressed pellet is prepared by grinding the sample to a fine, uniform powder, mixing it with a binder when required, and compacting it in a die under controlled pressure. The XRF pellet press page covers the press side of the process, and the 40-ton manual pellet press guide describes a complete boric acid pellet preparation procedure.

Pellet Dies for XRF Sample Preparation

The die determines the pellet diameter, the surface finish and whether the pellet can be removed without cracking. Options include rectangular dies (81–200 mm), cylindrical dies (81–200 mm) and round sample dies (41–80 mm) for larger pellets. For fluorescence applications, Hench also supplies the 40/32 mm fluorescent-specific borate die and the fluorescent special steel ring die; hard powders can be pressed with the sintered carbide die. See the pellet molding die series for the full range.

Grinding and Sample Preparation Consumables

Pellet quality starts with particle size and homogeneity. The HW-3 agate mortar is used for clean grinding without introducing contamination. Where an XRF instrument needs the fluorescence pressing route, the process is described in the fluorescence pressing machine guide.

Presses Used for XRF Pellets

Manual benches such as the 2/3/5/12/15-ton YP manual press and the YP-S digital press suit low-throughput laboratories. Higher volumes are served by the HAP-S automatic powder tablet press, the HAP-FS modular automatic press, the FTP-X automatic fluorescent tablet press and the HDP-J isostatic electric press. The laboratory hydraulic press range lists the complete line-up.

Applications

• Cement and clinker analysis in quality control laboratories
• Mining and geological samples, including remote mining laboratories
• Metals, alloys and catalyst powders
• Ceramics, glass and refractory materials
• Research laboratories developing new powder formulations

A field example is described in the Pakistan mining laboratory upgrade case.

How to Choose XRF Sample Preparation Equipment

• Sample volume: a manual press is sufficient for a few pellets per day; automatic presses are used for routine series.
• Pellet diameter: match the die to the spectrometer’s sample holder, from 32 mm up to 200 mm.
• Powder hardness: abrasive or hard powders benefit from carbide dies.
• Binder: boric acid or a similar binder is normally used as backing or as the matrix around the sample.
• Traceability: programmable automatic presses record pressure profiles for method documentation.

Frequently Asked Questions

XRF Sample Preparation Routes

Preparation route	Typical setup
Borate pellet	40-ton manual press with a borate die
Powder pellet	15-40 ton press with a steel-ring or carbide die
Large-format pellet	65-200 ton modular press with a matching die
Series preparation	automatic press with programmable cycles

Method Notes for XRF Pellets

Borate pellets are normally prepared as a 32 mm or 40 mm disc, and the die diameter has to match the sample holder of the spectrometer. Document the load and the hold time with the preparation record so that results can be compared between batches.

What press tonnage is needed for XRF pellets?

It depends on the pellet diameter and the powder. Our 40-ton manual pellet press guide describes a working set-up; for larger diameters or harder powders, 60-ton and higher presses are available in the press range.

Which die should I use for a borate pellet?

The 40/32 mm fluorescent-specific borate die is designed for borate pellets, and the steel ring die is used where a supporting ring is required.

Can the same press be used for FTIR and XRF samples?

Yes. A laboratory press can serve both workflows when it is paired with the appropriate die; the IR sample preparation guide covers the FTIR side.

Need help choosing the right configuration? Request a quote and include your sample type, required pellet or die size and the press you are using.