Definition
Basket sander is a kind of wet grinding and dispersing equipment, which is mainly used for ultra-fine grinding and dispersion of solid particles in liquid medium. Its core feature is the integration of grinding and dispersion functions in a liftable basket vessel with a built-in agitator and grinding medium, which is immersed in the slurry to be processed for cyclic processing. This equipment is widely used in the preparation of nanoscale particles in coatings, inks, dyes, electronic materials, and other fields.
Principle
Basket sanders operate on the principle of converting mechanical energy into particle surface energy. When the equipment is started, the motor drives the agitator in the basket to rotate at high speed, driving the grinding medium (such as zirconia beads) to form a strong vortex in the basket. The slurry to be treated is pumped or sucked into the basket under negative pressure, and the particles are sheared, collided and squeezed between the grinding media, and gradually crushed to the target particle size. The treated slurry flows out through the basket wall screen to achieve continuous cycle grinding. The energy transfer process can be simplified as follows: the input electrical energy drives the agitator to generate kinetic energy, which is converted into crushing energy for particles through the movement of the medium, and finally reflects the increase of the specific surface area of the particles.
Measurement and evaluation methods
The performance evaluation of basket sand mill is mainly based on the fineness and distribution of the treated material. Common measurement methods include laser particle size analyzers to determine particle size distribution, scraper fineness meters to assess maximum particle size, and viscometers to monitor changes in slurry rheological properties. The grinding efficiency can be quantified by the rate of particle size reduction per unit energy consumption, calculated as:
E = (d₀ - d₁) / (P · t)
E is the grinding efficiency coefficient, d₀ and d₁ are the initial and final characteristic particle sizes, P is the input power, and t is the processing time. In addition, changes in particle morphology can be observed by scanning electron microscopy to assess whether morphological damage is introduced during the grinding process.
Influencing factors
The grinding effect is affected by multiple parameters. In terms of grinding media, the density of the medium material affects the impact kinetic energy, and the diameter of the medium determines the number of contact points, and usually the diameter of the medium is positively correlated with the target particle size. In the process parameters, the stirring speed directly affects the shear force, but too high the speed may lead to excessive temperature rise. The filling rate needs to balance the collision frequency of the medium with the flow space. Material characteristics such as initial particle size distribution, solids content and slurry viscosity will affect the resistance of the medium. Among the structural factors of the equipment, the aperture of the basket wall screen determines the isolation effect of the medium, and the shape of the stirrer affects the distribution of the flow field. Environmental controls such as temperature management have a significant impact on heat-sensitive materials.
Applications
In the coating industry, it is used for ultra-fine dispersion of titanium dioxide and color paste to improve the gloss and coverage of coatings. In the field of ink, it is used in pigment grinding to improve the color saturation and stability of printing. In the processing of electronic materials, it is used for the homogenization of conductive pastes and ceramic powders. The field of new energy involves the nano-grinding of battery cathode and anode slurry. The dye industry uses it to control the particle size of dyes and improve coloring uniformity. In other fields where hygiene is high, such as cosmetics and food additives, gentle grinding can be performed using models that comply with hygienic design.
Selection considerations
Equipment selection should be based on a comprehensive evaluation of material characteristics and production requirements. In terms of material parameters, the initial particle size range, target particle size requirements, material hardness, solid content and corrosiveness need to be considered. Capacity requirements determine equipment volume and power configuration, and batch processing and continuous production correspond to different system designs. Material compatibility requires that the material in contact with the component (e.g., stainless steel, polyurethane) withstand the chemical properties of the material. The control system needs to pay attention to the speed adjustment accuracy, temperature monitoring and automation degree. Safety features include explosion-proof configuration, mechanical protection and emergency braking. Maintenance convenience involves the complexity of basket disassembly and assembly, seal replacement cycle, and cleaning feasibility. Energy efficiency assessment can be based on energy consumption data per unit of production.