Definition
Solid-liquid disperser is a mechanical equipment used to evenly disperse solid particles in liquid medium and form a stable suspension system. The equipment overcomes the agglomeration between solid particles by applying mechanical force to achieve depolymerization and uniform distribution of particles in the liquid phase. Its working process usually involves multiple stages such as wetting, depolymerization and stabilization, and is widely used in coatings, inks, nanomaterials, chemicals and food and other industrial fields, and is a key process equipment for the preparation of high-quality dispersion systems.
Principle
The working principle of the solid-liquid disperser is based on the theory of fluid mechanics and mechanical shear. The core component of the equipment is a rotor that rotates at high speed, which creates strong mechanical shear, impact and turbulence effects within the stator or vessel. When the solid particles and liquid mixture pass through the narrow gap between the rotor and the stator, they are subjected to extremely high shear rates, which breaks the agglomeration structure between the particles. At the same time, the cavitation effect and circulating flow generated by the equipment help the materials to be fully mixed, promoting the wetting of the liquid on the surface of the solid particles, and finally forming a uniform dispersion at the microscopic scale. The relationship between the basic energy input and the dispersion effect can be approximately expressed by the following formula:
E ∝ η · γ² · t
E represents the input energy, η is the viscosity of the system, γ is the shear rate, and t is the processing time.
Main measurement and evaluation methods
A variety of physical characterization methods were used to evaluate the dispersion effect of solid-liquid. Particle size distribution is the core index, which is usually measured by laser diffraction or dynamic light scattering, and the dispersion fineness is characterized by characteristic particle size parameters such as D50 and D90. The dispersion stability can be assessed by static observation of stratification time, centrifugal sedimentation experiments, or zeta potential measurements, and the higher the zeta potential value, the stronger the electrostatic repulsion between particles, and the more stable the system. In addition, viscosity measurements reflect changes in rheological properties, and microscopic observations (such as light or electron microscopy) can directly determine the aggregation status of particles. These methods are performed according to specific industry standards, such as ASTM or ISO-related standards, to ensure comparability and accuracy of results.
Key factors affecting the dispersion effect
The dispersion effect is affected by multiple factors. Equipment parameters include rotor line speed, rotor-stator clearance design, power density, and mixing chamber geometry, which determine shear strength and flow field distribution. Process parameters such as processing time, temperature control, dosing sequence and rate are also critical. In terms of material characteristics, the initial particle size, surface properties and concentration of solid particles, as well as the viscosity, polarity and surface tension of the liquid medium directly affect the difficulty of wetting and dispersing. In addition, the selection and dosage of dispersants can significantly change the solid-liquid interface energy and promote particle separation and stability. These factors should be taken into account during operation, and the process window should be optimized through experiments.
Typical application areas
Solid-liquid dispersers play an important role in several industrial sectors. In the coatings and inks industry, it is used to evenly disperse pigments and fillers in resin solutions, affecting the color, coverage and durability of the final product. In the preparation of nanomaterials, the equipment can realize the deagglomeration and stable dispersion of nanoparticles in the base solution. It is often used in the chemical field for the preparation of catalysts, pesticide suspensions and dyes. In the food industry, it is used for the homogenization of chocolate pulp, sauce and other products. In addition, in emerging or traditional fields such as battery slurry, ceramic slurry, and lubricating oil additives, solid-liquid dispersion processes are key links to ensure the consistency of product performance.
Key points for equipment selection considerations
The selection should be systematically evaluated based on process requirements and material characteristics. First, the target dispersion fineness, processing volume and continuity requirements should be clarified to determine the scale and type of equipment. For high-viscosity or high-solids systems, choose a model with abundant power, robust structure, and a reinforced shear design. Material compatibility must be considered, and the parts in contact with the material should be selected according to the corrosiveness and wear of the medium. Energy input efficiency and temperature rise control ability affect process economy and stability of heat-sensitive materials, and the equipment should have a good cooling design. Ease of use and maintenance, such as ease of disassembly and cleaning, seal reliability, and accessory versatility, are also important considerations for long-term operation. It is recommended to verify the suitability of the equipment through material testing and make decisions with reference to relevant industry application experience.