Many grades of CMC require relatively vigorous agitation to efficiently hydrate the individual gum particles. At the same time, aqueous CMC solutions must not be over-sheared to prevent permanent viscosity loss.
Purified sodium carboxymethyl-cellulose (CMC), also commonly known as cellulose gum, is an additive used in a broad range of applications throughout the food, cosmetics, pharmaceutical, paper, textile and other industries. It is added to improve viscosity, texture, mouthfeel, moisture retention, emulsion stability and other physical characteristics.
Because cellulose particles have a high tendency to agglomerate or lump upon contact with water, the method of dispersing and dissolving CMC is critical, particularly in a large scale setting wherein very slow powder additions cause serious process bottlenecks. Many grades of CMC require relatively vigorous agitation to efficiently hydrate the individual gum particles. At the same time, aqueous CMC solutions must not be over-sheared to prevent permanent viscosity loss.
The Ross Solids/Liquid Injection Manifold (SLIM) Technology is well proven for fast and complete dispersion of sodium carboxymethylcellulose (CMC) as well as other kinds of gums and thickeners. The SLIM consists of a unique rotor/stator generator specially designed to create a powerful vacuum that draws and injects powders directly into the mixer's high shear zone. Because solids and liquids are combined at precisely the point where intense mixing takes place, the formation of lumps and "fish eyes" is greatly reduced, if not eliminated. Just as importantly, powders are not left to float on the liquid surface for hours before they are completely dispersed or dissolved.
The SLIM technology is available in both batch and inline designs, making it simple to retrofit into existing processes. This system is used for dispersing small concentrations of powders like CMC (<2%) but it also routinely handles solid loadings as high as 70%, depending on the application, while operating within a wide viscosity range: from water-like to up to 10,000 cP during powder injection. After all the solids are added, product viscosity may continue to climb. For instance, batch SLIM rotor/stators are installed on Ross Multi-Shaft Mixers used for batching formulations with a final viscosity of several hundred thousand centipoise.