Powder grinding and nano-particle sizing: Sound, light and enlightenment

• Published in: Powder technology 2021-05, Vol.383, p.348-355
• Main Authors: Camargo, W.F., Mantas, P.Q., Segadães, A.M., Cruz, R.C.D.
• Format: Article
• Language: English
• Subjects: Crystallites; Crystals; Diameters; Dynamic light scattering; Electro-acoustic spectroscopy; Grinding; Light scattering; Mathematical analysis; Nanoparticles; Particle size; Particle size distribution; Particle size measurement; Photon correlation spectroscopy; Powder; Quartz; Sample preparation; Size distribution; Spectroscopy; Surface area; X-ray crystallite size; X-ray diffraction
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2021.01.059

In this work, a sub-micron quartz powder produced by high energy grinding was used to explore the information contained in the particle size distribution (PSD) curves obtained by electro-acoustic spectroscopy (EAS) and dynamic light scattering (DLS). Results show that although the customarily volume-based PSD curve and its median value (d50 = 135 nm) are more amenable to differences in measurement phenomena and sample preparation methods, the area and number-based representations are more sensitive to the presence of finer particles (35 and 65 nm, respectively for the number and area-based curves obtained by EAS). These values were supported by the crystallite size calculated from X-ray diffraction (d = 44 nm) and the equivalent spherical diameter calculated from specific surface area measurements (d = 43 nm). Thus, a reliable description of the particle size of a powder requires the use of complementary techniques, suggested by the envisioned application or the particular stringency of a given processing step. [Display omitted] •The particle size range of interest must guide the choice of base in the PSD curve.•The volume-based median particle size tolerates changes in measurement methods.•The DLS method is vulnerable to agglomeration in polydisperse size distributions.•Despite high solids concentration EAS promotes dispersion even for very fine sizes.•X-ray diffraction data strongly agrees with BET surface area-based particle size.