# Sedimentation of microparticles in Highly Concentrated Non-Newtonian Emulsions
## 3 Results
### Influence of Solid Parameters on the Sedimentation Process in Emulsion
The curves are not as smooth as in the previous cases. This may be indicative of clustered precipitation, where a larger number of particles fall together at one time. Obviously, the final sediment heights were relatively higher due to the larger number of particles in the system. The highest value of h\({}_{\text{sk}}\) was obtained for beads with sizes of 300-400 \(\upmu\)m.  
To explain the effect of the amount of sediment on the sedimentation process in the emulsion, the scheme presented in Figure 8 was used. Assume that the solid particle is large enough that its weight is able to overcome the emulsion structure, that is, to force the oil droplets to move aside to create a flow channel for the particle (Figure 5b). Considering the number of particles in the system, three cases can be distinguished. In the first, shown in Figure 8a, there is a small number of particles in the system. In this situation, the particles affect only the neighboring droplets, moving them from their track. The remaining emulsion droplets (which are not in direct contact with the particles) remain unaffected. In this case, the flow resistance is low; therefore,  
Figure 8: (**a**–**c**) Scheme of transport of solid particles through the emulsion structure at different concentrations (amounts) of particles. Figure 7: Dependence of (**a**) sediment layer height and (**b**) sedimentation velocity during the process for the sedimentation of microspheres with a concentration of 0.4 g/mL in an 70% emulsion, \(\text{d}_{\text{e1}}\). sedimentation can occur intensively, and in this case, the sediment layer grows rapidly. Another case occurs when the number of beads in the system is so large that in order for a particle to get through the emulsion structure, it must affect not only the neighboring droplets but also the remaining ones (Figure 8b). In this case, the flow resistance is higher. However, there is enough space in the system to create a track for the particles to fall, so sedimentation also occurs in this case. However, when there are very many particles in the system, the oil droplets of the emulsion are so compressed by the particles that they form a barrier for the particles through which they cannot pass. This is schematically illustrated in Figure 8c. In this case, the flow resistance is greatest. For sedimentation to occur, the particles must deform the spherical shape of the droplets. An important conclusion from these studies is that there is a certain optimum particle size ratio relative to the emulsion droplets at given concentrations at which the sedimentation process occurs. When the particle size is too small, its weight is too small to overcome the resistance of the oil droplets. In this situation, the particles are trapped in the emulsion structure. When the particles are too large, the structure of the system becomes so compact that the oil droplets act as a barrier to the particles. Additionally, the amount of particles in the system is an important factor. When the number (concentration) of particles in the system is low enough, there is enough space for the particles to break through the emulsion structure. After exceeding a certain quantity, the structure of the system becomes compact, and the emulsion droplets block the particles' descent.