Introduction
In high solid content slurries, dispersants must be able to handle higher density particles, thus requiring greater stability than dilute systems. Main requirements include stronger adsorption, dual stabilization mechanisms, precise dosing, and compatibility with the specific chemical and physical characteristics of the slurry.
Challenge of high solid content：
High solid content brings many challenges that dispersants must overcome: □ High particle density: Enhanced interaction between particles makes agglomeration more likely, increasing viscosity and leading to sedimentation. □ Reduced free volume: The liquid space available for particle movement decreases, which increases resistance and makes dispersion more difficult to achieve and maintain. □ Thickening and gelation: Highly viscous or gelled slurries with poor dispersibility may form, hindering flow and processing. □ Caking: During mining and transportation, if the slurry does not remain fluid, poor dispersibility can cause solid particles to 'cake' in pipes or tanks, and dispersants help prevent this phenomenon. |  |
Key dispersant requirements：
To address these challenges, dispersants used in high-solid-content slurries must possess specific properties.
Powerful and stable mechanism：
◇ Electrostatic Steric Stabilization: The most effective high-solids dispersants combine both electrostatic and steric effects. ◇ Electrostatic Repulsion: Adsorbed molecules on the particle surface carry charges, generating repulsive forces that keep particles separated. ◇ Steric Hindrance: Polymer chains extending from the particle surface form a physical barrier, preventing particles from coming too close and aggregating. ◇ Strong Multi-point Adsorption: Dispersants must have strong "anchoring" groups capable of firmly adhering to the particle surface, preventing desorption under shear or prolonged action. For polycarboxylates, this is achieved through multiple anchoring points on the polymer chain. ◇ High Molecular Weight: Dispersants used in high-solids systems typically have high molecular weights to provide sufficient steric hindrance and cover a larger particle surface area. Long polymer "tails" are crucial for forming effective repulsive barriers in dense slurries. |  |
High-solids ceramic slurries, due to their high particle density and small free volume, impose stricter requirements on dispersants. Successful dispersion solutions rely on dual stabilization mechanisms combining electrostatic repulsion and steric hindrance, and maintain slurry stability in a dense particle environment through the strong anchoring effect of high-molecular-weight polymers and the barrier function of long chains. A thorough understanding of the unique challenges of high-solids systems and the key performance requirements of dispersants is the foundation for achieving efficient ceramic forming processes and high-quality product manufacturing.