(587h) Segregation Analysis of Free-Flowing Powders Using the Spectester: Impact of Particle Size Ratio

Achieving uniformity in powder blends is essential for ensuring consistent product quality across industries such as pharmaceuticals, food processing, chemical manufacturing, and powder metallurgy. Segregation in these systems is primarily driven by differences in particle properties such as size, density, and shape. Among these, particle size disparity plays a particularly significant role, with larger size differences leading to more pronounced segregation.

This study focused on investigating the impact of particle size ratios on the segregation behavior of free-flowing powder blends, including (1) developing and validating a novel sample preparation technique integrated with the Near-Infrared (NIR) spectrometer SPECTester to improve segregation quantification, enhance content uniformity assessment beyond conventional relative standard deviation (RSD) methods, and reduce material use and sampling errors; (2) standardizing a Near-Infrared (NIR) probe-based segregation tester using disparate granular materials to ensure consistent, repeatable, and accurate results; and (3) assessing the impact of particle property-based segregation drivers, including particle size ratio, density ratio, and shape, on segregation intensity of free-flowing powder blends.

Experimental analyses were conducted on binary free-flowing, mostly spherical powder blends with six different particle size ratios and relevant physical properties. The results revealed a strong correlation between particle size ratios and segregation intensity. Blends with greater particle size ratios consistently exhibited higher segregation tendencies, emphasizing the necessity to control particle size distribution during formulation. Additionally, while density and shape also contributed to segregation behavior, their effects were less significant than those of particle size.

These findings highlighted the importance of controlling particle size ratios to mitigate segregation and improve uniformity in free-flowing powder systems. The approach developed in this study provided a practical method for segregation quantification and could support improved formulation strategies and process control to enhance overall product quality.