Bentonite Property

Density 

2~3g/cm3

solubility 

Practically insoluble in water and in aqueous solutions. It swells with a little water forming a malleable mass.

form 

powder

color 

Light yellow or green, cream,pink, gray to black solid

Odor

odorless, sl. earthy taste

Water Solubility 

Insoluble in water and forms a colloidal solution.

Merck 

14,1055

Exposure limits

ACGIH: TWA 1 mg/m3

Dielectric constant

8.1（Ambient）

Stability:

Stable.

CAS DataBase Reference

1302-78-9

EPA Substance Registry System

Bentonite (1302-78-9)

Safety

Risk Statements 

20/22-8

Safety Statements 

22-24/25

WGK Germany 

3

RTECS 

CT9450000

TSCA 

Yes

Hazardous Substances Data

1302-78-9(Hazardous Substances Data)

Toxicity

LD50 intravenous in rat: 35mg/kg

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Warning

Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P321Specific treatment (see … on this label).

P332+P313IF SKIN irritation occurs: Get medical advice/attention.

P362Take off contaminated clothing and wash before reuse.

Bentonite Chemical Properties,Usage,Production

Description

Bentonite is a light yellow, creamy, palebrown or gray to black powder or granules. These chemicals contain 1- 24% crystalline silica (O2Si). Specificgravity (H2O:1)=2.5. Hazard Identification (based onNFPA-704 M Rating System): Health 2, Flammability 1,Reactivity 0. Insoluble in water

Chemical Properties

Bentonite is a light yellow, creamy, pale brown or gray to black powder or granules.

Chemical Properties

Bentonite is a crystalline, claylike mineral, and is available as an odorless, pale buff, or cream to grayish-colored fine powder, which is free from grit. It consists of particles about 50–150 mm in size along with numerous particles about 1–2μm. Microscopic examination of samples stained with alcoholic methylene blue solution reveals strongly stained blue particles. Bentonite may have a slight earthy taste.

Uses

As of Fuller's earth; as emulsifier for oils; as a base for plasters. Pharmaceutic aid (suspending agent).

Uses

filler in cosmetics and other products, gel, or solid if dry

Uses

bentonite (bentonite clay) is used to regulate the viscosity and suspension properties of a cosmetic formulation. It also acts as an overall formula stabilizer. Bentonite’s water-absorption capabilities allow it to form a gelatinous mass. Considered a noncomedogenic raw material, bentonite is a colloidal aluminum silicate clay.

Uses

Bentonite is a general purpose additive that is used as a pigment and colorant and to clarify and stabilize wine.

Definition

A type of clay that is used as an adsorbent in making paper. The gelatinous suspension it forms with water is used to bind together the sand for making iron castings. Chemically bentonite is an aluminosilicate of variable composition.

Production Methods

Bentonite is a native, colloidal, hydrated aluminum silicate, found in regions of Canada and the USA. The mined ore is processed to remove grit and nonswelling materials so that it is suitable for pharmaceutical applications.

General Description

Bentonite is comprised primarily of the smectite group (montmorillonite) of clay minerals. It is widely used in various industrial applications such as clarification of edible and mineral oils, paints, cosmetics, and pharmaceuticals. It is also used as an adsorbent for the elimination of pollutants from wastewater.
The swelling property of bentonite is used to produce viscous water suspensions for bonding, plasticizing, and suspending applications. The presence of a large surface area of bentonite is due to the colloidal dispersion of the particles is the main reason for its application as an insecticide carrier, an emulsifier, and an emulsion stabilizer.

Agricultural Uses

Clays exist in many forms, of which montmorillonite is one form. Kaolinite and montmorillonite, which are clay minerals, have different layer structures with differing abilities to absorb and retain water, and to adsorb and exchange cations.
Montmorillonites have an expanding structure (2: 1) and have high cation exchange capacity (80 to 120 mg per 100 g). They have abundant black clay soils. Other minerals in this group are biedellite and nontronite.

Pharmaceutical Applications

Bentonite is a naturally occurring hydrated aluminum silicate used primarily in the formulation of suspensions, gels, and sols, for topical pharmaceutical applications. It is also used to suspend powders in aqueous preparations and to prepare cream bases containing oil-in-water emulsifying agents.
Bentonite may also be used in oral pharmaceutical preparations, cosmetics, and food products. In oral preparations, bentonite, and other similar silicate clays, can be used to adsorb cationic drugs and so retard their release. Adsorbents are also used to mask the taste of certain drugs.
Bentonite has been investigated as a diagnostic agent for magnetic resonance imaging.
Therapeutically, bentonite has been investigated as an adsorbent for lithium poisoning.

Agricultural Uses

Bentonite, also known as montmorillonite, volcanic clay, soap clay and amargosite, is a soft, plastic, lightcolored, porous rock consisting largely of colloidal silica. Composed essentially of clay minerals, it swells extensively when wet. Bentonite belongs chiefly to the montmorillonite group and has two varieties: (a) sodium bentonite, with a high swelling capacity in water, and (b) calcium bentonite, with negligible swelling capacity.
Bentonite is used variously as a suspending aid, a gelatinous slurry to extinguish fire, a paint thickener, and as a sealant for earthen pots. Bentonite is also widely used in metallurgy, soap manufacture, and in petroleum refining because of its high decolorizing power and strong adsorbing capacity.

Safety Profile

Poison by intravenous route causing blood clotting. Questionable carcinogen with experimental tumorigenic data.

Safety

Bentonite is mainly used in topical pharmaceutical formulations but has also been used in oral pharmaceutical preparations, food products, and cosmetics.
Following oral administration, bentonite is not absorbed from the gastrointestinal tract. Bentonite is generally regarded as a nontoxic and nonirritant material.
LD₅₀ (rat, IV): 0.035 g/kg

Potential Exposure

This material is used as Fuller’s earth; as a mineral, natural, or synthetic fiber; as an emulsifier for oils; as a base for plasters; in cosmetics, in polishes and abrasives; as a food additive and others. Bentonites are aluminate silicate and can contain crystalline silica. The content varies widely from less than 1% to about 24% .

First aid

Inhalatio Move person to fresh air. Seek medical attention if necessary. Skin: Wash with water. Eyes:Wash with water as needed. Seek medical attention if necesvsary.

storage

Bentonite is hygroscopic, and sorption of atmospheric water should be avoided.
Aqueous bentonite suspensions may be sterilized by autoclaving. The solid material may be sterilized by maintaining it at 1708℃ for 1 hour after drying at 1008℃.
Bentonite should be stored in an airtight container in a cool, dry place.

Shipping

Bentonite is not cited in the DOT Performance- Oriented Packaging Standards.

Incompatibilities

Substance is a weak acid in water; avoid contact with strong alkaline material. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.

Incompatibilities

Aqueous bentonite suspensions retain their viscosity above pH 6, but are precipitated by acids. Acid-washed bentonite does not have suspending properties. The addition of alkaline materials, such as magnesium oxide, increases gel formation.
Addition of significant amounts of alcohol to aqueous preparations will precipitate bentonite, primarily by dehydration of the lattice structure.
Bentonite particles are negatively charged and flocculation occurs when electrolytes or positively charged suspensions are added. Bentonite is thus said to be incompatible with strong electrolytes, although this effect is sometimes used beneficially to clarify turbid liquids.
The antimicrobial efficacy of cationic preservatives may be reduced in aqueous bentonite suspensions, but nonionic and anionic preservatives are unaffected.
Bentonite is incompatible with acriflavine hydrochloride.

Waste Disposal

Land fill disposal.

Regulatory Status

Accepted in Europe as a food additive in certain applications. Included in the FDA Inactive Ingredients Database (oral capsules, tablets and suspensions, topical suspensions, controlled release transdermal films and vaginal suppositories). Included in nonparenteral medicines licensed in the UK. Included in the Canadian List of Acceptable Non-medicinal Ingredients.