Action Mechanism and Process of Grinding Dispersants​

The action mechanism and process of grinding dispersants involve the synergistic effect of physicochemical interactions and mechanical dynamics. Their core function is to enhance grinding efficiency by achieving uniform dispersion of particles through wetting, dispersion, and stabilization.

1.Mechanism of Action
Wetting and Penetration‌

The dispersant reduces the interfacial tension between the carrier and the solid particles, facilitating the penetration of the liquid into the particle accumulation. This process can be compared to the liquid infiltration in the capillary model, effectively reducing the flow resistance and creating conditions for subsequent mechanical dispersion.‌

Electrostatics and spatial stability

Electrostatic repulsion: Anionic dispersants (such as ammonium polyacrylate) adsorb onto the particle surface, forming a double layer, which increases the Zeta potential to inhibit agglomeration.

Spatial steric hindrance: High-molecular-weight dispersants form a coating layer on the particle surface, which physically hinders the re-aggregation of particles.

Auxiliary grinding effect

The dispersant reduces the cohesion between particles, thereby lowering the energy consumption for grinding. For instance, lignin dispersants with high sulfonation degree, due to their good solubility and low viscosity, can significantly enhance the grinding efficiency.

Grinding process:

Pre-mixing stage‌
The raw materials and deionized water are initially mixed in the mixing tank. At this stage, the dispersant begins to wet the surface of the particles, forming a macroscopically uniform suspension.

Fine Grinding Stage​‌

Mechanical force action: The grinding media (such as zirconia beads) in the sand mill crush particles through impact, shear, and extrusion, while the dispersant simultaneously adsorbs onto the newly formed surfaces to prevent re-agglomeration.

Dynamic equilibrium: The grinding process involves a reversible reaction of "coarse particles → fine particles," and the dispersant must maintain sufficient coverage to drive the forward reaction.

Slurry stabilization

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The slurry after grinding needs to maintain uniform suspension through the stabilizing effect of the dispersant. For example, high-temperature-resistant dispersants can ensure the stability of continuous production in ceramic slurries.

Key influencing factors

Dispersant type: Anionic types (e.g., lignosulfonates) are suitable for dye grinding, while nonionic types are more applicable to organic systems.

Grinding equipment: Shear-type (e.g., three-roll mills) and impact-type (e.g., sand mills) have different requirements for energy density and medium viscosity.

Process parameters: The addition amount of dispersant must be precisely controlled, as excessive amounts may reduce efficiency.

Through the synergy of these mechanisms and processes, grinding dispersants achieve full-process optimization from particle deagglomeration to long-term stability.