Bentonite is the naturally occurring clay of monmorillonite. Bentonite is commonly of two types, one is swelling and other non-swelling. Sodium bentonite is generally of swelling type and calcium bentonite is of non-swelling type. Sodium bentonite is generally suited as binder in the preparation of pellets, foundry and drilling mud. Bentonite acts as suspending agent in oil well drilling fluids.
Calcium bentonite is suitable for de-colourising purposes. It is also activated before use to enhance its absorption property when required for bleaching.
Ca Based Bentonite Natural Lumps
- Properties
- Colour: Pale yellow to reddish yellow
- Form: Lumps / Powder
- Monmorilonite % : 85%
- LOI : 6.9%
Na Based Bentonite Natural Lumps
- Properties
- Colour : Greenish Yellow to brownish red
- Form: Lumps / powder
Chemical Analysis
| Aluminium Oxide Al2O3 | 12 to 16% |
| Silica SiO2 | 45 to 55% |
| Ferric Oxide Fe2 O3 | 15% |
| Titanium Oxide TiO2 | 1.5 to 2.5% |
| Calcium Oxide CaO | 1.0 to 1.6 |
| Potesium Oxide K2O | 0.1% |
| Sodium Oxide Na2O3 | 3% |
| Loss on ignition L.O.I. | 15% max |
Foundry Grade Bentonite
| Physical Properties And Characteristics | Grade A | Grade B | Grade C |
|---|---|---|---|
| MOISTURE | 9-13% | 9-13% | 9-13% |
| BASE EXCHANGE CAPASITY | 90.00min | 85.00min | 80.00min |
| SWELLING CAPACITY of ASTMD 5890:1995 | 30-35 | 25-30 | 22-25 |
| GELLING TIMEIS: 12446-1998 | Instantaneous | Instantaneous | Instantaneous |
| GEL FORMATION INDEXIS:12446-1998 | 75-85 | 60-75 | 50-60 |
| LIQUID LIMIT | 700-800 | 600-700 | 500-600 |
| PH VALUEIS:6186-1986 | 9.4-9.6 | 9-9.5 | 9-9.5 |
| GREEN COMPRESSIVE STRENGTH Bent:Water – 10:4 IS:12446-1986 | 12-13 | 12-13 | 12-13 |
| METHYLENE BLUE ABSORPTIONISO:10416-2002 | 400-450 | 380-400 | 350-380 |
| SIEVE ANALYSIS% passing through 100 Mesh | 98min. | 98min. | 98min. |
| % passing through 200 Mesh | 85min. | 85min. | 85min. |
