Ultrasonic spectrometry measures the attenuation of a sound wave propagating through a sample. In slurries the ultrasound signal becomes highly attenuated as a function of particle size, concentration and density. To monitor these properties in slurries the attenuation requires interpretation using a mathematical model. We examine different sizes of silica suspended in water, at different concentrations, and frequencies up to 100 MHz. We determine that a new multiple scattering theory inclusive of shear-wave reconversion effects (i.e. conversion of compressional wave to shear wave and back to compressional wave at the particle/liquid boundary) is successful for attenuation prediction in the range up to ::120 MHz and 20% (by volume). Beyond this level the model with shear-effects begins to deviate from the real attenuation, but is still more representative of the experimental results than modelling only an incident compressional wave. Thus, shear-wave reconversion modelling is essential to more accurately reflect the attenuation spectra in a solid particle in suspension system, and dictates the ultrasonic attenuation as particle sizes decrease and concentration increases. (C) 2016 The Author(s). Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.