The processing of granular materials is often associated with dust emissions that arise from the mechanical or fluid-induced detachment of microscale dust particles adhering to macroscale bulk particles. The dustiness of granular materials depends, among other factors, on the adhesive forces between individual particles. Moisture content, which is governed by the ambient relative humidity, influences these interparticle adhesive forces and thus affects dust emission behavior. For the numerical prediction of dust emissions, a quantitative determination of interparticle forces is therefore essential. Consequently, investigating the influence of moisture content on adhesion forces between particles in bulk materials is crucial for understanding and predicting dust emissions. One method for measuring adhesive forces at the particle scale is atomic force microscopy (AFM).

This study presents an experimental setup designed to determine the adhesive forces between microscale and macroscale particles. The measurements are carried out in a custom-built climate chamber equipped with integrated humidification and dehumidification units, ensuring a defined relative humidity during the measurement process. Force-distance curves are recorded using an AFM and subsequently analyzed to quantify the adhesion forces. By systematically varying the relative humidity in each measurement series, its influence can be investigated in a controlled manner.

The study reports initial measurement results, identifies key challenges, and outlines corresponding solution approaches....