Thickener

A thickener is a substance added to a liquid to increase its viscosity, or a device used in mineral processing to separate solids from liquids. In rheology, thickeners are typically polysaccharides, gums, cellulose derivatives, or synthetic polymers that swell in water to form a gel-like network, increasing resistance to flow. They are used to adjust texture, stabilize emulsions, suspend particles, and control pourability. Common food-grade thickeners include starches (cornstarch, potato starch), hydrocolloids (xanthan gum, guar gum, locust bean gum), and cellulose derivatives (carboxymethyl cellulose). Industrial thickeners include polyacrylates, polyurethanes, and associative thickeners used in paints, coatings, and inks.

In mining and wastewater treatment, a thickener is a clarification or settling tank in which solids settle and a concentrated slurry forms; the overflow water clarifies. In drilling fluids, thickening agents control viscosity and gel strength to suspend solids. In paints and coatings, thickeners modify rheology to improve brushability and sag resistance. In foods and cosmetics, they improve mouthfeel and stability, while in pharmaceuticals they help control release and stability.

Selection depends on pH, ionic strength, temperature, shear, compatibility with other ingredients, and regulatory status. Safety considerations include that many food thickeners are generally recognized as safe by regulatory authorities, while industrial thickeners require appropriate handling per material safety data sheets.