The dispersion of magnesium hydroxide is actually particle dispersion. Particle dispersion refers to the process in which powder particles are separated dispersed in a liquid medium evenly distributed throughout the liquid phase. It mainly includes three stages: wetting, deagglomeration, stabilization of dispersed particles. The following small series introduces the dispersion method of magnesium hydroxide.
1. Mechanical dispersion method, etc.
Mechanical dispersion is a method to fully disperse the nanoparticles in the medium with the help of mechanical energy such as external shear force impact force. Mechanical dispersion methods include grinding, ordinary ball milling, vibration ball milling, colloid milling, air milling, mechanical agitation, etc. This method is a commonly used method of dispersing ultrafine powders, but it is easy to introduce impurities may change the physical chemical properties of the powder.
2. Ultrasonic method
Ultrasonic dispersion is to place the particle suspension to be treated directly in the sound field process it with ultrasonic waves of appropriate frequency power. It is a high-intensity dispersion method. The mechanism of ultrasonic dispersion is cavitation, which can produce local high temperature high pressure, generate huge impact force micro jet. Under its action, the surface energy of the nano powder is weakened, which can effectively prevent the agglomeration of particles to make it full. dispersion.
3. Chemical dispersion method
Chemical dispersion is to choose one more suitable dispersants to improve the dispersion of the suspension, improve its stability rheology. Commonly used dispersants are:
①Small molecular weight inorganic electrolyte inorganic polymer, such as sodium silicate, sodium aluminate, potassium tripolyphosphate, etc. This type of dispersant can be dissociated charged. Adsorption on the surface of the powder can increase the surface potential of the particles, increase the electrostatic repulsion, improve the stability of the slurry. Its mechanism of action is static repulsion stability.
②Surfactant, this type of dispersant is composed of two parts, lipophilic group hydrophilic group, is an amphiphilic molecule, including long-chain fat, CTAB, etc. Mainly steric hindrance effect, the hydrophilic group is adsorbed on the surface of the powder, the hydrophobic chain extends into the solvent, which has a good effect on improving the rheology of the slurry.
The above are several methods of magnesium hydroxide dispersion, I hope it can help everyone.
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