| Attapulgite is a kind of crystalloid hydrous magnesium-aluminum
silicate mineral, having a special laminated chain structure in
which there is a crystalline lattice displacement existed. Thus
it makes the crystals contain uncertain quantities of Na+, Ca+,
Fe3+ and Al, and present in the shape of needles, fibers or fibrous
clusters. Attapulgite has very good colloidal properties such as:
specific features in dispersion, high temperature endurance, salt
and alkali resistance, and also high adsorbing and de-coloring capabilities.
Furthermore, attapulgite has certain plastic and adhesive characters.
Its ideal molecular formula is:
Mg5Si8O20(HO)2(OH2)4•4H2O.
The structure is somewhat between laminated and chain structure.
Attapulgite looks like soil, and compact blocks which are found
in the sedimentary rocks and the weathering crust. Attapulgite are
white, hoar, caesious or celadon, or with some dim mercerization
in color. The clay of attapulgite is fine and a bit greasy smooth,
light in weight, crispy, and the fractured surface is like shells
or in irregular shapes. Attapulgite has strong ability to absorb
water. When it is wet, attapulgite shows plastic and adhesive properties;
and when it gets dry,attapulgite does not shrink much and does not
show cracks. When it is soaked in water,attapulgite collapses. The
suspending liquid does not create soliquids and precipitates, when
meeting electrolytes.
Attapulgite clay mineral resources distribute in only several countries
in the world at the present. Attapulgite reserve capacity of Xuyi
contains the 70% in China, and 35% in the world. Compared to the
largest commercial attapulgite deposits in the United States, Xuyi
attapulgite products have the following special features:
Because the geological conditions under which Chinese attapulgite
was deposited are different from that of the USA attapulgite deposits,
our attapulgite products have very low grit (percentage retained
on a 325 mesh wet screen), low free silica content, and low carbonate
content.
Selectively mined and processed attapulgite products have a very
high dispersion viscosity and API yield. The products processed
from naturally occurring mixtures of attapulgite show especially
high dispersion viscosity, high API yield, and extremely low grit.
As = 0.5
Pb = 1
Hg = 0.3
Toxicological test result of the attapulgite: Both Nanjing Municipal
Sanitation and Antiepidemic Station and Nanjing Municipal Foodstuff
Research Institute have carried out "The Comprehensive Sanitation
and Safety Assessment on the Attapulgite Clay, a Natural Foodstuff
Processing adjuvant". Their test results are as follows: Such
heavy metals as arsenic, lead and mercury are not detectable in
the attapulgite clay product, while total iron, sulfates, chlorides,
nitrites, etc. are within the limits called for by the standards
for processing adjuvant concerned. The tests on the content of the
natural radioactive nuclide 238V,232TH,226Ra,40K,
and the natural R radiation dosage at the surface of the mining
area show that in the original ore and in the product those figures
are lower than that in the natural background value, therefore they
are within the normal range. The Ames test reveals negative results
and there is no positive reaction on the micronucleus incidence
rate of the polychromatic erythrocytes in the bone marrow chromosome
of mice. The max non-reaction dosage to animals is 9,909.01mg/kg,
showing that the test material is very safe to the health of humans
and animals. |