Where is Bentonite proper, found?
Bentonite minerals occur as seams or lenses containing up to 50% moisture.
Because deposits are rocklike in nature they are usually extracted by quarrying
(opencast mining). We are informed that most high-grade, commercial, “Sodium
Bentonite” mined in the United States, comes from the area between the Black
Hills of South Dakota and the Big Horn Basin of Montana.
A great website for the geography of other such locations is:
http://www.mindat.org/min-9141.html (This author found only one ambiguous
entry, i.e., while the holotype referenced therein evidently came from Wyoming
and is referred to as a Fort Benton Shale, one should not infer that Fort Benton
is also in Wyoming, but rather recognize that it is in fact in Montana, as
previously set forth herein.)
Thus, we see Bentonite
as a rather common mineral complex occurring all over the world and at many
locations in each of States within the continental USA. “Calcium Bentonite” is
supposedly even more common than the “Sodium Bentonite” variety. Further, we
might infer that a number of the historical locations for
Bentonite more accurately were actually
for Montmorillonite, and vice versa.
Historical perpetuation of the apparent confusion seems
to have been rampant. Nevertheless, if a true distinction can be made should we
assume Montmorillonite to be any less
common? This author believes that answer to be a resounding, “Yes”. If we are
able to segregate out the Montmorillonites from the broader
group called Bentonites with any kind of consensus, then and only then can we
prove this hypothesis. Another challenge would be to further attempt to grade
known deposits according to fresh water formations and those formed under the
influence of salt water. Famous minerals such as limestone and dolomite were
definitely formed in shallow marine environments and are much older than the
Montmorillonoids.
Alas, such an exercise is not within the scope of
undertaking the clarification attempted herein, and the writer leaves it to more
highly trained chemists, geologists with the USGS and university professors,
professional metallurgists, soil scientists, and the like. The hypothesis that
the two varieties of clay can be more articulately segregated once and for all,
satisfying a globally-accepted objective standard, might be the basis for some
future dissertation. The dichotomy is certainly a provocative one in light of
the balance of this presentation. Nevertheless, there seem to be on the Web,
nearly as many authoritative sources holding for the distinction, as there are
neophyte opinions favoring the jumbled approach.
a)
Use as a foundry sand, bleaching clay (Fuller's Earth), cleaning and
filtering agent, an aid to effect water impedance, employment as an additive to
ceramic materials, cement tiles, concrete, plaster, sheetrock and other forms of
insulation, and agent in iron ore palletizing.
b)
Providing colloidal benefits with application to such industries as
cosmetics, personal care products (suspending agent, gellant and binder),
pharmaceutical, and household products (crayons, paste, shoe polish, paint
thickener, etc.)
c)
Water proofing and lubricating grease.
d)
Additive in packaging and inks, and the making of jars, pails, drums,
paper bags, copy paper, bulk bags and fiberboard containers, and
e)
Other such diverse and peculiar purposes including as an ingredient in
cat litter, dynamite, and matches.
One website suggests that commercial grade
Bentonite may be represented as:
SiO2=
61.3% and Al2O3= 19.8%,
--quite different figures
from the edible clay, Montmorillonite!
Which would you rather eat?
There appears to be a
consensus that both Bentonite
and
Montmorillonite
have a vast array of properties and benefits with some cross-over into
industrial and nutritional applications by both. But given the preference by
industry for Bentonite which would you rather
eat?
One “manufacturer”
of Montmorillonite warns:
Generally speaking, make sure the label on the
clay you take says “Montmorillonite,” as
Bentonites and other types of clay can contain overwhelming amounts of certain
minerals that could pose potential danger to the system. Both
Montmorillonite and Bentonite clays belong to the
Smectite family, … however,
Montmorillonite is purer, more complex clay with greater exchange capacities.
Its ability to adsorb and absorb toxins makes it the most preferred species of
edible clay.
Furthermore, the method of
preparation for market of Bentonite is vital.
An important study in Brazil indicated grinding was detrimental to Bentonite.
In addition to aggregation of the particles,
large grinding times originated damage to the structure on the bentonite,
interlayer collapse and Al-Mg remotion from octahedral sheet of near 30%.
Nevertheless, the characteristic type of Montmorillonite remaining in the ground
sample was preserved and the interlayer collapse was reversible after
rehydration. Aggregation in thick particles reduced suspension viscosity.
With these views before
us, two things come to mind:
1) If
Bentonite is superior as an industrial agent,
why waste valuable
Montmorillonite
to do
what Bentonite does better?
2)
If
“pure” Montmorillonite
is
uniquely suited to assist agriculture and to benefit other organisms
nutritionally, why would a serious formulator want to risk the effects of the
added minerals that differentiate Bentonite?
The intelligent approach would seem to be to use both
minerals, respectively, for their strengths and not spend lots of money trying
to eliminate some things from one, or adding them to the other.
3
By "broader", despite the historical explanations/implications wherein
Montmorillonite was formerly considered to be an appropriate synonym for
Smectite, it is hoped that the ultimate acceptance of a distinct, or purer clay
to be precisely termed "Montmorillonite" is in fact a major component of what
henceforth shall be universally accepted as Bentonite. Thus, albeit
Montmorillonite, as a unique stand-alone formulation, is always present in
Bentonite, it is the other ingredients such as substantial amounts of Sodium, or
Calcium, and perhaps more significant amounts of iron and other elements that
render Montmorillonite, "Bentonite". Hence, in this context, Bentonite,
has the broader pedigree.
Page 5 The Diatoms