The mean particle size and suspension density of industrial ammonium sulfate and urea crystals were measured by a single ultrasound sensor in a saturated solution at only one frequency. The information on ultrasound velocity and attenuation were combined and related to characteristic properties of the solid phase of suspensions. By model identification, a correlation between the measured signals and mean particle size as well as suspension density were evaluated and verified by additional experiments. The measurements with different particle size fractions and different suspension densities up to 40 wt-% were carried out isothermally. The approach of coupled ultrasound velocity and attenuation provides a simple technique for inline process control on the liquid and solid state of a suspension process like solution crystallization only by a single measurement device.

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To test the application of in situ coating as an alternative coating technology, pastilles drop-formed from molten mixtures containing xylitol and isomalt were produced. The efficiency and usability of the classical nucleation techniques in this practical application could be demonstrated. Besides the influence of power ultrasound and seeding, the effect of a combination of both on nucleation at the shell of the drop-formed melt mixtures was examined. Microscopic cross-section pictures illustrate the impact on quality of the coating layer of drop-formed pastilles.

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The coating process is a crucial step in conventional industrial tablet production. Here, a simpler method to coat the tablets is realized by melt crystallization technology. Phase separation of the mixture components, which need to be eutectic, is investigated for lauric acid and ibuprofen. Use of a colored complex of lauric acid, the expected phase separation was visualized. Post-production analyses confirmed the two different solidifying phases. Variation of certain parameters within the drop forming simulation experiment, to test their effects on the tablet geometry and phase separation, provided an important entry in the tablet coating formula. Cooling the crystallizing drops from the top and the bottom resulted in the generation of evenly coated tablets, a major goal in tablet production.