Chemical Properties
gel, or solid if dry
Usage
filler in cosmetics and other products, gel, or solid if dry
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
Inhalation: Move person to fresh air. Seek medical
attention if necessary. Skin: Wash with water. Eyes:
Wash with water as needed. Seek medical attention if necessary.
Ingestion: Seek medical attention if necessary.
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.
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
Waste Disposal
Land fill disposal.
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
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.
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.
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
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.
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.
