Three Forms of Precipitated Silica

Precipitated silica, depending on its physical properties and micro-structure, can be broadly classified into the following three forms:

1. Powder Form

Appearance Characteristics: Fine white powder with high dispersibility and a smooth, slippery texture. Under a microscope, the particles are irregularly shaped, with a wide size distribution ranging from tens to hundreds of nanometers.

Formation Process: Sodium silicate reacts with acid to form hydrated silica, which is then filtered and washed to remove impurities. Through a drying process, the water in the hydrated silica evaporates, ultimately forming powdered silica.

Performance Characteristics and Applications:

Specific Surface Area: 150-250 m²/g.

Applications: Used as a reinforcing agent in the rubber industry to enhance the strength, wear resistance, and tear resistance of rubber products; acts as a thickener and anti-settling agent in coatings and inks to improve rheological properties and storage stability.

2. Micro Pearl Form

Appearance Characteristics: Micro pearl form with particles that are approximately spherical or spheroidal, ranging in size from tens to hundreds of micrometers. It has better flowability and is less prone to dusting compared to the powder form.

Formation Process: By precisely controlling reaction conditions (such as temperature, pH, and reactant concentration) and adding granulating agents or using specialized drying techniques, hydrated silica particles aggregate and form larger granules.

Performance Characteristics and Applications:

Specific Surface Area: 100-200 m²/g.

Applications: Used as a filler in the plastics industry to improve hardness, rigidity, and dimensional stability; enhances processing and performance properties in powder coatings and pesticide powders.

3. Granular Form

Appearance Characteristics: Solid blocks with relatively large volume and certain mechanical strength. The size and shape of the blocks can be adjusted according to production needs.

Formation Process: Hydrated silica naturally dries and solidifies under specific pressure and temperature conditions, or binders are added to promote particle adhesion, resulting in block-shaped silica.

Performance Characteristics and Applications:

Specific Surface Area: 80-150 m²/g.

Applications: Used as an additive in refractory materials to improve high-temperature resistance and mechanical strength; suitable for long-term storage and transportation due to its ease of handling and reduced dust generation. It can be crushed or ground as needed before use.