Emulsifiers

In normal atmospheric conditions, Bitumen and water can't mix and will separate instantly. Emulsifiers are speciality chemicals used to stabilize the fine dispersion of bitumen droplets in water. Depending on their chemical properties, emulsifiers are of two major types: Cationic and Anionic.

Cationic emulsifiers provide a fine emulsion under strong acidic conditions, where normally concentrated hydrochloric acid is used for adjustment of final pH.

On the other hand Anionic emulsifiers provide a stable bitumen emulsion under strong alkaline condition, where normally Sodium Hydroxide is used for adjustment of final pH.

The emulsifiers can be ionic products which require neutralization/ Acidification/ Alkalisation at the time of emulsion production or can be a pre-neutralized and pH fixed (Ready), requiring no acid / alkali at the time of bitumen emulsion production.

CATIONIC EMULSIFIERS :

• Cationic emulsifiers are used to produce the large volume and most popular type of Bitumen Emulsions called "Cationic Bitumen Emulsions". These are the most commonly used Bitumen Emulsions in the world for road and highway applications.
• The bitumen droplets in Cationic Bitumen Emulsions carry a positive charge, so special type of low dose emulsifiers are used for their production which are generally treated with concentrated hydrochloric acid in water phase for their "activation".
• There are two broad range of Cationic Emulsifiers: Conventional (which require neutralization with HCl) and Ready (Ready to use product without modification) Emulsifiers.
• These emulsifiers are further divided into Emulsifiers for Rapid / Medium Setting Cationic Bitumen Emulsions and Emulsifiers for Slow Setting Cationic Bitumen Emulsions. The details are given below: