Definition
Liquid-solid disperser is a mechanical equipment used to evenly disperse solid particles in liquid medium to form a stable suspension system. The equipment overcomes the agglomeration tendency between particles through mechanical action, realizes the refinement and uniform distribution of particles in the liquid phase, and is widely used in many industries and scientific research fields such as chemicals, coatings, food, and new energy materials.
Principle
The working principle of the liquid-solid disperser is based on high-speed shear, impact and turbulence effects. The core components typically include a rotor rotating at high speed with a fixed stator, or a similar high-shear structure. When working, the rotor rotates at high speed within the stator, creating a strong mechanical shear force. After the solid aggregates are sucked into the working chamber, they are subjected to high-frequency shear, violent impact and hydraulic tearing in the narrow gap between the rotor and stator, so that they are quickly broken into fine particles and fully mixed with the liquid medium. The whole process can be described as converting mechanical energy into surface energy to reduce particle size and increase its specific surface area, thereby promoting the formation and stabilization of dispersion systems.
Main measurement and evaluation methods
To evaluate the liquid-solid dispersion effect, a number of indicators need to be combined. Particle size distribution is the core parameter, which is often measured by laser particle size analyzer, and the dispersion degree is characterized by characteristic particle sizes such as D50 and D90. System stability can be assessed by observing the resting stratification time, measuring the sedimentation rate, or using centrifugal stability tests. For high-concentration suspension systems, viscosity and its change over time or shear rate are also important indicators and can be measured using a rotary viscometer. In addition, the microscopic dispersion and agglomeration of particles can be directly observed through microscopy or scanning electron microscopy.
Influencing factors
The dispersion effect is affected by multiple factors. In terms of equipment parameters, rotor line speed, rotor-stator clearance design, shear time, and equipment power input are key. Process parameters include temperature control, feeding sequence and rate of the dispersion process. The material properties have significant influences, such as the initial particle size, hardness, shape, and surface properties of solid particles, as well as the viscosity, polarity, and surface tension of liquid media. Formulation factors, such as the choice and dosage of dispersants, can significantly improve dispersion stability by changing the surface charge or steric resistance of the particles.
Applications
Liquid-solid dispersers play an important role in many industrial and R&D fields. In the coating and ink industry, it is used to evenly disperse pigments and fillers in resin bases, which directly affects the color, coverage and stability of products. In the field of nanomaterial preparation, it is used for the deagglomeration and stable dispersion of nanomaterials such as carbon nanotubes and graphene in base liquids. In the lithium battery industry, it is used for the homogeneous mixing of electrode slurries (active substances, conductive agents, binders). In addition, liquid-solid dispersion is also an indispensable key process in the production process of cosmetics, pesticide preparations, ceramic slurries, food additives, etc.
Key points to consider in selection
Selecting a suitable liquid-solid disperser requires systematic consideration. The process objectives need to be defined first, including the characteristics of the material being processed (e.g., viscosity range, solids content, particle hardness), target particle size, batch throughput volume, or continuous processing capacity. According to the viscosity and dispersion difficulty of the material, the shear strength and power density of the required equipment are judged. Consider whether the equipment material meets the requirements of corrosion resistance, wear resistance, and hygiene level. Pay attention to the operability and process controllability of the equipment, such as whether it has speed regulation, temperature control, vacuum or pressurization functions. In addition, equipment is easy to clean and maintain, operating noise and safety protection measures should also be included in the assessment. It is recommended to verify the suitability of the equipment for a specific material through a small or pilot test.