What is Bentonite/Activated Clay?
Published On:January 17, 2020 Revised On:January 11, 2023

What is Bentonite/Activated Clay?

What is Bentonite/Activated Clay?

Activated Clay, or Bentonite, is an absorbent aluminium phyllosilicate clay where a large portion is made up of the element montmorillonite. This is a widely used natural desiccant used primarily for the protection of industrial packaging. The dry clay desiccant is in the form of slightly coarse granules compared to silica gel and inserted and used in the same sachet as the standard material. Due to high efficient dehydrating qualities and the value of money, clay is an excellent alternative to silica gel in all general packaging applications.

If you ever open a Bentonite Clay desiccant sachet, you will find very fine brown, grey powder. This powder can be abrasive, making it unideal for packaging highly sensitive equipment like cameras, video cameras, binoculars, microscopes, or other delicate materials. You might be thinking that if the name is “Activated Clay,” it means that the clay undergoes some chemical processing. But the clay or bentonite does not experience any chemical substance during the processing stage. The process of manufacturing Bentonite is:

  1. It is extracted in the quarry
  2. The Bentonite is then crushed to form finer granules of it
  3. It is heated in an oven to remove any traces of moisture present inside of it
  4. The product is then packaged in packets of various sizes and shipped

The absorption capacity of Activated Clay desiccant is nearly identical to that of Silica Gel. Still, since Bentonite is a direct natural compound that does not undergo any chemical processes, the adsorption capacity varies from batch to batch. Due to this reason, Bentonite packages are varied from absorption capacity, which is identified in dehydrating units instead of weights. According to the NFH technical standards, one dehydrating unit is the quantity of clay necessary to absorb 6 grams of water vapour under 40% relative humidity and 23°C temperature conditions.

Types of Bentonite

Sodium Bentonite

Sodium Bentonite expands when it absorbs moisture. Its colloidal properties are widely used to drill mud and oil gas wells and boreholes for applications like geotechnical and environmental investigation. The expansion property also makes Sodium Bentonite a great sealant since it provides qualities like self-sealing and a low permeability barrier. It is mostly used to line the base of landfills. Due to various surface modifications of Sodium Bentonite, there is an improvement in the rheological or sealing performance of geoenvironmental applications—for example, the addition of polymers.

Calcium Bentonite

Calcium Bentonite is widely used as an absorbent of ions in a solution. Additionally, fats and oil can also be absorbed. It is one of the most active ingredients of the fuller’s earth, probably the earliest industrial cleaning agent. Calcium Bentonite can be converted to Sodium Bentonite with the help of the ion exchange procedure.

Potassium Bentonite

Potassium Bentonite is also known as potash bentonite or K-bentonite. It is a potassium-rich illicit clay formed due to changes in the molecular structure of volcanic ash.

Applications of Activated Clay

Activated ClayPurification

Bentonite is used for the decolourisation of various minerals, vegetables, and animal oils. It is also used for clarifying fluids like wine, liquor, cider, beer, mead, and vinegar.

Drilling Mud

The main application of Activated Clay is for drilling mud binder and as a groundwater barrier. Since 1990, almost 50% of Bentonite in the United States is used for drilling mud. It is used in drilling fluids to cool and lubricate the cutting tools, remove cuttings, and prevent any possible blowouts in the machinery. At high concentrations, the Bentonite suspension starts taking the form of a gel. So, it is a common component of drilling mud by preventing the formation of mud cake.


Bentonite has been most widely used as a foundry-sand bond in iron and steel foundries. Sodium Bentonite is mostly used for larger castings that use dry moulds, whereas Calcium Bentonite is helpful for the smaller castings that use “green” or wet moulds. It is also used as a binding agent in the steel industry for iron ore pellets. A small percentage has been used as an ingredient in commercial and homemade clay bodies and ceramic glazes. It increases the plasticity of the clay body and decreases settling in the glaze, which makes both components easier to use. The self stickiness property of Bentonite makes it easy to be modelled into any shape or form.


Activated Clay has the property to absorb a large number of protein molecules from liquids or simply water. As a result of this property, Bentonite is uniquely useful in the process of winemaking, as it removes the excessive amount of protein from white wines. If Bentonite desiccant was not used in this procedure, the clear white wine might’ve turned into a hazy white or cloudy white colour after exposure to a particular temperature. It also reduces the time required for the process of clarification of white and red wine. It is also used in various pet care items to absorb odours. Additionally, it can be used to absorb oil and grease.


Bentonite is used as the base of many dermatologic formulas. Granular Bentonite is used to fabricate and study battlefield wounds. It is also sold online and in various retail outlets for a variety of indicating applications.


Bentonite is also used as a desiccant due to its absorbing properties. These desiccants protect pharmaceutical, nutraceutical, and diagnostic products from degradation due to moisture and extend their shelf life. In many standard packages, Activated Clay provides a higher absorption capacity than silica gel. It complies with FDA for contact with food and drugs.

Emergency Applications

Bentonite is used in industry and emergency applications as a chemical absorbent and as a container sealer. This is all about Bentonite or Activated Clay. In some applications, it is advantageous over Silica Gel, and in others, vice versa.

To know more about the Activated Clay desiccants, do feel free to contact us!