Bentonite

The mineral with a thousand uses

Bentonite is a very soft plastic clay consisting predominantly of montmorillonite, a fine particle-sized hydrous aluminum silicate and member of the smectite group. Most bentonites are formed by the alteration of volcanic ash and rocks after intense contact with water. Bentonite presents strong colloidal properties and increases its volume several times when coming into contact with water, creating a gelatinous and viscous substance. Its specific properties include swelling, water absorption, viscosity, and thixotropy. These properties are in demand in a huge range of industries served by Imerys, earning it the nickname ‘the mineral with a thousand uses’.

Physical properties

• Strong colloidal properties 
• Swells in contact with water
• Water absorption 
• High viscosity 
• High plasticity 
• Thixotropy

World-class Bentonite operations in Europe and South Africa 

Imerys operates benchmark bentonite mines and processing plants on the island of Milos in Greece, in the southern Cape, South Africa, in the US, China, Hungary, and Bulgaria.

Imerys operations supply consistent high-quality bentonite to serve oil drilling, paper industry, tunnelling, dam, lake and landfill sealing, water treatment, pet litter, and feed markets worldwide.

A critical constituent in foundry castings and other applications

In foundry making, Imerys bentonite is a critical constituent in the casting of high-quality foundry products where it is used as a binder for the production of green sand molds to ensure defect-free final castings. Bentonite binders are cost-effective, environmental solutions since the majority of the sand and binder can be reused in a cyclical system. 

In iron ore pelletizing Imerys bentonite is used as a binder for the formation of iron ore pellets. Pellets are balls produced from iron ore or concentrates and are used as feed material for iron making. Imerys bentonite adds significant value to the pelletizing process and the quality of the final product.

Bentonite is used in drilling and tunnelling fluids to lubricate and cool cutting tools, remove cuttings and help prevent blowouts. It is a common component in drilling mud used to curtail drilling fluid invasion due to its propensity to aid in the formation of mud cakes.

Imerys sealing bentonites are suitable for sealing liners in earth construction, waste deposits, water engineering, and lakes due to their high water absorption capacity as well as high swelling potential, ensuring low water permeability in the application.

In the paper industry, the high surface area of bentonite in combination with its unique properties makes it ideal for various applications. Bentonite is used in retention systems and for the control of stickies and pitch. Furthermore, it helps to improve the loop water treatment which reduces water consumption.

Bentonite is ideal for use in cat litter due to its unique water absorption, swelling, and odour-controlling properties. It is an excellent anti-caking agent for animal feed. 

With demand for bentonite likely to rise in most of its applications, bentonite markets are slated to grow over the next few years.