Dispersant refers to a surfactant that can quickly wet the surface of solid particles, and can raise the energy barrier between solid particles to a high enough. It can effectively improve the particle wetting of the slurry under the condition of low moisture content. Wetness, suspension stability and slurry rheology, and make the slurry have appropriate viscosity, to achieve the purpose of energy saving and consumption减少。优秀的dispersants play several roles in wetting, grinding, diluting and stabilizing during the preparation of ceramic slurries, which play an important role in improving the performance of ceramic products and reducing manufacturing costs.
润湿的影响
Wetting usually refers to the process where the interface between particles is replaced by the interface between particles and solvent, dispersant, etc. The dispersion of the powder is better in a solution with a lower critical surface tension than its own, that is, in a dispersion medium with the same surface tension, the higher the surface tension of the powder, the smaller the contact angle between the medium and the particles, the wetting and dispersibility The better. In order to improve the dispersion of the powder, effective additives must be used to reduce the surface tension of the medium.
Grinding effect
The crushing of raw materials is an important part of the ceramic preparation process, especially the crushing to the micron-level particle size consumes more energy and time. In the wet ball milling process, due to the collision, proximity, and attraction of molecules or particles, the powder is often prone to agglomeration, and the phenomenon of "reverse grinding" occurs, that is, in the crushing process, when the material reaches a certain fineness, the grinding continues. There will be a phenomenon of thicker and thicker. The addition of dispersant can be firmly adsorbed on the cracks of the particles and can penetrate deep into the cracks. The new interface formed during the particle crushing process is quickly wrapped by the dispersant, which hinders the recombination of the new interface and accelerates the crushing process, significantly shortening Crushing time, save energy consumption and improve grinding efficiency.
Dilution effect
Ceramic slurry requires both high solids content and good fluidity. Adding a certain amount of dispersant can effectively reduce the viscosity of the slurry, and at the same time can appropriately reduce the amount of media used, which is beneficial to reduce the subsequent processing process. Energy consumption.
Stabilization
Without the addition of dispersant, particles in water are mainly subjected to the following four forces: gravity, buoyancy, particles, water interfacial tension, and the interaction force between particles, which leads to easy sedimentation of particles and poor slurry stability; After adding the dispersant, since the dispersant is adsorbed on the surface of the particles, the surface of the original particles is partially or completely covered by the dispersant, which hinders the agglomeration of the particles and improves the suspension and stability of the slurry.