Antiscalants

Antiscalants are agents that delay the process of limescale formation.

Limescale is formed by precipitation and crystallization of salts poorly soluble in water, such as sulphates of barium, calcium, strontium and calcium carbonate.  The accumulation of limescale in systems significantly reduces the flow by clogging them. In order to prevent undesirable process of limescale formation, antiscalants should be used to protect system components and extend their lifetime. Antiscalants have the ability to bind metals present in ionic form in the water. They form complex compounds soluble in water preventing the formation of limescale.

The majority of antiscalants are surface active compounds which operate in three ways:

• Through dispersion – they disperse salt particles forming the limescale by adhering to them and reducing their negative charge. As a result, the crystals are separated from each other and are unable to reconnect.
• Through inhibition of the threshold level – they maintain saturated solutions of poorly soluble salts in the water, preventing their precipitation.
• Through modification of crystals – they distort the crystals. This results in forming uneven, oval structures that disrupt the processes of crystalline lattice formation, thereby preventing limescale build-up.

Antiscalants are used mainly in closed water circuits.  They are used in boilers, cooling systems in power plants and in industrial osmotic stations. They operate both in cold and hot water. The most effective antiscalants are those based on phosphates, which also have anti-corrosive properties.