Details
Bentonites are hydrated aluminosilicate minerals, comprised chiefly of montmorillonite. Structurally they consist of alumina sheets sandwiched between tetrahedral SiO4 units. Water is usually present between the triple layers.
Typical Chemical Analysis.
SiO2 57.74%
Al2O3 18.23%
Fe2O3 3.09%
CaO 1.93%
MgO 4.19%
K2O 3.03%
Na2O 1.72%
P2O3 0.13%
TiO2 0.39%
Mn3O4 0.08%
V2O5 <0.05%
Cr2O3 <0.05%
Typical Physical Properties.
Bulk Density 800-900 Kg/m3
pH 6
Swelling Volume 8 ml/2g
Moisture 14% maximum
CEC 85-90 meq/100g
Sieve Analysis
150 microns Max 5% retained
75 microns 15-25% retained
Source: Spain
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