Bentonite OCMA:

 16 m3/tone (min)

 Yield point

 15ml (max)

 Water loss

 10% (max)


 2 w.t % (max)

 Residue on ASTM sieve No: 100 (dry method)

 2.5 w.t % (max)

 Residue on ASTM sieve No: 200 (water method)



Bentonite (API):

 30 (min)

 Viscometer Dial, 600 rpm

 3 (max)

 Yield Point/ Plastic Viscosity Ratio

 15 ml (max)

 Filtrate Volume

 4%w (max)

 Residue Greater than 75 µm

Bentonite (for steel industry):

 600%w (min)

 Wate absorption (plate test method)

 6%w (max)


 20%w (max)

 Residue on ASTM sieve No:325


Bentonite (for foundry):

 Sodium bentonite

 Chemical composition


 Gelling (after 24 hours)


 Swelling factor (2g)



 75%w (min)

 Methylene blue absorption



 1100 (0°C)

 Sinter point


 Loss on Ignition (LOI)

 750-950 g/cm2

 Green compressive strength

 17-20 g/cm2

 Green Tensile strength


 Residue on ASTM Sieve No.200


The main uses of bentonite are for drilling mud, binder (e.g. foundry-sand bond, iron ore pelletizer), purifier, absorbent (e.e. pet litter), and as a groundwater barrier. As of around 1990, almost half of the US production of bentonite was used for drilling mud.