Free Flow - Improvement of Flowability and Caking Tendency

Copper sulfate without and with addition of SIPERNAT®

Automation has more and more found its way into the production and the use of powders. Automated processes, however, demand a good flowability facilitating clean and precise dosing. Besides this caking during storage needs to be avoided. This is challenging as there are many powder products on the market showing bad flowability and tending to cake during storage. This leads to undesired downtime in production. SIPERNAT^® products offer a highly efficient possibility to solve these problems and to increase productivity.

The flowability of powders is affected by the relation of adhesive forces, so-called Van-der-Waals forces, and by gravity. Van-der-Waals forces are present in any powder. In relation to gravity, these forces are the higher, the smaller the particles are. For this reason finely sized powders show a worse flowability than coarser powders do.

Besides this there may be some more reasons for a bad flowability:

• Liquid on the surface of powder particles, such as water or oil (e.g. in hygroscopic or oily powders), keeps them together by surface tension.
• Unevenly sized particles may hook to each other.
• Some powders get electrostatically charged to the walls or pipes during transportation.

SIPERNAT^® precipitated silica consists of fine particles which envelop the powder to be treated. In this case SIPERNAT^® acts as a spacer between the individual particles separating them and, thus, reducing the adhesive forces. In addition it absorbs the moisture or oil from the surface preventing the formation of liquid bridges.

For highly hygroscopic powders hydrophobic SIPERNAT^® grades offer an even more effective solution. Due to their water-repellent character they float on the water film coating the powder particle. Thus they separate the particles preventing the formation of water bridges.

Further Evonik-products for flowability improvement:

Besides the wide range of SIPERNAT^® grades Evonik also offers different AEROSIL^® products as flow aid and anti-caking agent.

Carrier - Application as Carrier Substance

Synthetic silica have found their way into several industries with numerous applications, where production processes have become more and more automated. For this purpose powders are preferred, which can be dosed precisely and safely. Most suitable are freely flowing, non-dusty powders, which do not cake and preferably are microgranular. SIPERNAT^® grades offer an efficient possibility to meet these challenges and increase productivity.

Synthetic silica serve as excellent carrier substances for liquid or pasty products. This is an efficient way to improve handling and dosing of sticky or highly viscous liquids, providing a homogeneous distribution of valuable additives. The resulting free flowing powders and granulates can be mixed easily with other dry products at any concentration.

SIPERNAT^® grades have proven as excellent carrier substance for years. SIPERNAT^® is highly absorptive, free flowing, chemically inert, and physiologically safe.

The advantages when using SIPERNAT^® products are:

• Dust-free concentrates
• Free flowing powders
• Protection against caking
• Precise dosing
• Constant quality
• Cost reduction 

Vitamin E-acetate as oil and on SIPERNAT® 2200