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The dispersion of certain powdered solids such as xanthan gum, guar, carrageenan, carboxymethylcellulose (CMC), alginates and other thickeners into a liquid phase are particularly difficult because they resist wetting out. When mixed with a traditional turbine or paddle agitator in a kettle, they float stubbornly for hours on the surface of the batch. Even when processed using high speed mixing devices such as saw-tooth dispersers that generate a strong vortex on top of the batch, these powders may still take a long while to hydrate completely. Rather than break down and wet out, they often form agglomerates and “fish eyes,” which are very difficult to break apart. “Fish eyes” are agglomerates of partially hydrated powders characterized by a tough outer layer which prevents the complete wetting of particles within the interior.
