Definition

Noun: A highly absorbent, fine-grained clay consisting primarily of montmorillonite, formed from the weathering of volcanic ash. It is characterized by its ability to swell significantly when mixed with water.

Usage

Bentonite is used as a material due to its unique properties of absorption, swelling, and plasticity. * It is commonly employed as a binding agent in foundry sands for metal casting. * In civil engineering, it is used as a sealant in slurry walls and to stabilize boreholes. * Its absorbent qualities make it useful in pet litter and as a clarifying agent in winemaking.

Examples

• The geologist identified the layer of bentonite as a key marker for dating the sedimentary rock.
• Drillers use a bentonite slurry to prevent the walls of the well from collapsing.
• This facial mask contains bentonite clay to help draw out impurities from the skin.

Advanced Usage

• Sodium Bentonite: A type with high swelling capacity, often used for sealing ponds and landfills.
• Calcium Bentonite: A type with lower swelling capacity but better absorption properties, often used in clarifying agents and absorbents.

Variants and Related Words

• Montmorillonite (n): The primary mineral constituent of bentonite clay.
• Fuller's Earth (n): A similar, highly absorbent clay material, sometimes used interchangeably with bentonite in certain contexts, though they have different mineral compositions.

Synonyms

• Absorbent clay
• Swelling clay
• Volcanic clay

Related Phrases/Compounds

• Bentonite slurry: A viscous mixture of bentonite and water used in drilling and construction.
• Bentonite seal: A barrier created using bentonite to prevent fluid migration.

Noun

1. an absorbent aluminum silicate clay formed from volcanic ash