In the dispersion process of high-viscosity slurries, issues such as "not being dispersed despite being mixed" and "remaining clumps" occur. The main cause of these problems is that the increase in viscosity reduces fluidity, preventing dispersion energy from being evenly transmitted throughout the system. Generally, dispersion breaks apart agglomerated particles through shear force, but in a high-viscosity state, the flow becomes localized, leading to differences between areas experiencing shear and those that do not. As a result, undispersed areas and agglomerates remain, causing variations in particle size distribution and quality issues. Furthermore, the higher the viscosity, the weaker the circulation within the equipment, making it difficult for particles to pass uniformly through the processing area, which also decreases reproducibility. In batch processing, variations in residence time and mixing state become particularly pronounced, making it easier for lot differences to occur. To achieve stable dispersion in high-viscosity systems, not only shear enhancement but also flow design and ensuring circulation are important. By simultaneously controlling flow and shear, as in inline continuous processing, uniform and highly reproducible dispersion can be achieved. Additionally, the wettability of the powder and the method of introduction during the initial dispersion are also crucial; if the initial dispersion is insufficient, the subsequent breaking efficiency decreases.

Even slurries that appear uniform after dispersion often face challenges of instability in quality due to sedimentation and separation over time, which is commonly observed in many settings. This phenomenon is not merely a result of insufficient stirring; it is influenced by the aggregation state of the particles, a lack of dispersion energy, and complex inter-particle interactions in the liquid. Particularly in the case of nanoparticles or high solid content slurries, even slight dispersion issues can significantly affect sedimentation behavior, leading to variations in product performance. Additionally, batch processing is susceptible to changes in state over time, making it difficult to ensure reproducibility. To suppress sedimentation, it is crucial to not only mix but also to break down particles to the primary particle level and achieve uniform dispersion. Furthermore, maintaining consistent shear conditions, as in inline continuous processing, can help stabilize the dispersion state and ensure uniform quality. Designing the dispersion state throughout the entire process is key to producing stable slurries that do not sediment.