Precipitated silica, also known as silica gel, is a fine, white, porous, non-crystalline form of silica produced by artificial means. It is synthetically manufactured by neutralizing a soluble silicate with an acid resulting in the formation of a gel-like precipitate. The precipitate is washed to remove salt and then dehydrated to produce a high-purity amorphous form of silica.

Properties and Uses of Precipitated Silica

Precipitated silica has several important properties that make it useful for various industrial applications. Its high porosity, absorptive qualities and purity profile significantly expand its usage potential.

High Purity and Absorptive Qualities

With a pore structure in the nanoscale range, silica gel has a very high surface area and absorptive capacity. This makes it useful as a dehydrating agent or desiccant to absorb moisture in various materials and applications. Its high purity and chemical inertness also allow its use as a food-grade anti-caking and anti-lumping agent in powdered foods.

Enhanced Physical Properties

When added as a reinforcing filler in rubber, plastics and other polymers, silica gel improves physical properties like tensile strength, tear resistance, heat resistance, Young's modulus and surface hardness. Precipitated Silica is used extensively in automobile and truck tire manufacturing to enhance tread performance and fuel efficiency.

Specialty Applications

Given its amorphous nature, silica gel can soak up oil and solvents without changing shape. This makes it suitable for use as an adsorbent in oil and grease filters. Its absorptive properties and purity also find applications in oral care, healthcare and animal nutrition industries. Recent research has explored use of silica gel in bone grafts, wound dressings and controlled drug delivery systems.