Anticaking agents are used in such things as table salt to keep the product from forming lumps, making it better for packaging, transport, and for the consumer.
An anticaking agent in salt is denoted in the ingredients for example as "anti-caking agent (554)", which is sodium aluminosilicate, a man-made product. This product is present in many commercial table salts as well as dried milks, egg mixes, sugar products, and flours. In Europe, sodium ferrocyanide (535) and potassium ferrocyanide (536) are more common anticaking agents in table salt. Natural anticaking agents used in more expensive table salt include calcium carbonate and magnesium carbonate.
Some anticaking agents are soluble in water, others are soluble in alcohols or other organic solvents. They function either by adsorbing excess moisture or by coating particles and making them water repellent. Calcium silicate (CaSiO3), a commonly used anti-caking agent, added to e.g. table salt, adsorbs both water and oil.
Anticaking agents are also used in non-food items such as road salt, fertilisers and cosmetics, and in manufacturing applications.