Foundry grade bentonite for green sand moulding
Soda-activated bentonite binder for iron and steel foundries, supplied to a stated green compression strength, active clay content and fineness, tested on every lot.
AFS test methods · IS 12446
Foundries do not buy montmorillonite percentage. They buy green compression strength at a known addition rate, and a binder that behaves the same way next month as it did this month.
Our foundry grade is activated in our own yard, aged so the ion exchange completes before it is dried, and ground fine so it disperses quickly in the muller.
We supply it in containers to foundries abroad and by truck to foundry clusters in India.
Where it is used
Foundry grade bentonite specification
Foundry grade
AFS standard sand mix · buyer specification
| Property | Test method | Unit | Our typical | Guaranteed range |
|---|---|---|---|---|
| Green compression strength | AFS, standard sand mix | g/cm² | 1,450 | 1,300–1,600 |
| Dry compression strength | AFS, standard sand mix | kg/cm² | 6.2 | 5.0–7.5 |
| Wet tensile strength | AFS | N/m² | 2,900 | ≥ 2,500 |
| Active clay (methylene blue) | MB titration | % | 78 | ≥ 72 |
| Swell index | ASTM D5890 | mL/2 g | 24 | ≥ 22 |
| pH, 2% suspension | pH meter | — | 9.8 | 9.3–10.5 |
| Passing 75 µm (200 mesh) | Wet sieve | % | 92 | ≥ 88 |
| Moisture as shipped | Oven dry, 105 °C | % | 10.2 | ≤ 12.0 |
Typical usage
Set by your sand system. Most green sand systems run 6–8% active clay; make-up additions replace the clay burnt out at each cast. Send us your current binder's figures and we will run a side-by-side trial before you switch.
Packing and shipping
25 kg laminated PP bags, sealed. Floor-loaded at 1,040 bags, 26.0 MT net per 20ft container, with desiccants fitted. Jumbo bags on request.
MOQ one 20ft FCL · CFR or CIF · Mundra Port
Frequently asked questions
What is green compression strength?
The load at which a rammed specimen of moist moulding sand fails, measured with the AFS standard method. It tells a foundry whether a mould will hold its shape when the pattern is drawn and the metal is poured.
Is soda-activated bentonite suitable for ductile iron?
Yes. Sodium-activated bentonite gives the hot strength and durability that high-pressure green sand lines need. Some steel foundries blend it with calcium bentonite to adjust flowability.
Do you supply foundries in India?
Yes. Foundry grade goes by truck to Indian foundry clusters and by container to foundries abroad. Ask for a sample and a quotation delivered to your city or port.
Can we trial it before switching?
Yes. We send a 2.5 kg sample with its certificate of analysis so you can test it against your current binder at your own addition rate.
Other products: Drilling gradeCivil / piling gradePelletising gradePlastic white clay
Test it against what you buy today.
A 2.5 kg sample with its certificate of analysis, sent by DHL or FedEx. Tell us your current supplier's figures and we will tell you honestly how ours compare.