Bentonite ball mill (also called bentonite grinding mill or activated clay ball mill) is a specialized grinding equipment used to produce finely ground bentonite powder for a wide range of industrial applications. Bentonite is a clay mineral primarily composed of montmorillonite, known for its unique properties: swelling, thixotropy, high water absorption, and cation exchange capacity. These properties must be preserved during grinding – over‑grinding or excessive heat can destroy the layered structure and reduce performance.
Bentonite ball mill (also called bentonite grinding mill or activated clay ball mill) is a specialized grinding equipment used to produce finely ground bentonite powder for a wide range of industrial applications. Bentonite is a clay mineral primarily composed of montmorillonite, known for its unique properties: swelling, thixotropy, high water absorption, and cation exchange capacity. These properties must be preserved during grinding – over‑grinding or excessive heat can destroy the layered structure and reduce performance.
Our bentonite ball mill is designed for gentle, temperature‑controlled dry grinding. The mill operates in a closed circuit with an air classifier, allowing precise control of particle size while maintaining low mill temperature (outlet <80°C). As a professional ball mill manufacturer, we provide complete bentonite processing lines including drying (if raw moisture >10%), grinding, classification, and optional sodium activation (conversion of calcium bentonite to sodium bentonite).
Applicable materials: sodium bentonite, calcium bentonite, activated bentonite, and fullers earth.
Step 1 – Pre‑Drying (if needed)
Raw bentonite (moisture 15–30%) is dried in a flash dryer or rotary dryer to <10% moisture.
Step 2 – Sodium Activation (optional)
Dried bentonite is mixed with 2–5% soda ash in a mixer, then aged for 24–72 hours.
Step 3 – Feeding & Grinding
Activated or natural bentonite (≤20 mm) is fed into the ball mill. The mill contains small‑medium balls (Φ15–50 mm) with low‑lifting liners. Water spray cooling keeps mill temperature low.
Step 4 – Air Classification
Ground material is lifted to a dynamic air classifier. Rotor speed determines cut point. Fines (
Step 5 – Collection
Fine bentonite powder is collected by a bag filter (with anti‑static filter bags if needed). Product moisture is typically 6–10% to preserve swelling.
Step 6 – Packing
Powder is packed into bags (25/50 kg, or bulk) for shipping.
Bentonite’s value depends on its montmorillonite structure. Our mill design protects it: Closed‑circuit operation – fine particles removed immediately, no over‑grinding Low grinding temperature – water spray cooling on shell + high airflow (outlet <80°C) Gentle grinding action – short cylinder, low‑lifting liners, small media (Φ15–40 mm) Result: High swelling yield (>80 bbl/ton for sodium bentonite) and stable viscosity.
Bentonite is notorious for sticking to equipment. Our solutions: Rubber or polyurethane liners – reduce adhesion Polished steel liners – smooth surface Air sweeps – blow material off grinding media Hydrophobic coating of liners (optional)
Different applications require different fineness: Drilling mud (API): 200 mesh (75 µm) with <30% <200 mesh, >85% <200 mesh is typical Foundry sand: 100–200 mesh (150–75 µm) Pelletizing: 200 mesh (75 µm) with high Blaine (400–500 m²/kg) Cat litter / absorbents: 6–20 mesh (coarse granules, not milled) Our dynamic air classifier produces narrow PSD with adjustable cut point (d97 = 38–150 µm). PLC control maintains consistency.
We offer two optional upgrades: Drying‑grinding mill – accepts bentonite with 12–15% moisture, using hot gas (150–200°C) to dry during grinding. Eliminates a separate dryer. Sodium activation system – mixer + aging pugmill to convert calcium bentonite to sodium bentonite (add 2–5% soda ash). Improves swelling yield by 50–100%.
| Model | Dia.×Length (m) | Capacity (t/h) * | Fineness (Mesh) | Motor Power (kW) |
|---|---|---|---|---|
| Φ1.5×3.5m | 1.5×3.5 | 2–3 | 200 | 55 |
| Φ1.83×4.5m | 1.83×4.5 | 4–6 | 200 | 110 |
| Φ2.2×5.5m | 2.2×5.5 | 6–9 | 200 | 185 |
| Φ2.4×6.5m | 2.4×6.5 | 10–14 | 200 | 280 |
| Φ2.6×8m | 2.6×8 | 14–20 | 200 | 400 |
| Φ3.0×9m | 3.0×9 | 20–28 | 200 | 630 |
| Φ3.2×10m | 3.2×10 | 28–35 | 200 | 1000 |
Capacity for sodium bentonite, feed ≤15mm, moisture <10%, target 200 mesh. Add 20% for calcium bentonite (easier to grind).
| Model | Capacity (t/h) | Fineness (Mesh) | Power (kW) |
|---|---|---|---|
| Φ2.4×6.5m | 8–11 | 325 | 280 |
| Φ2.6×8m | 12–17 | 325 | 400 |
| Φ3.0×9m | 17–24 | 325 | 630 |
| Parameter | Value |
|---|---|
| Max. feed size | ≤10–20 mm |
| Output fineness (d97) | 150 – 38 µm (100 – 400 Mesh) |
| Product moisture | 6 – 10% (adjustable by drying) |
| Feed moisture (dry mill) | ≤10% (higher requires pre‑drying) |
| Grinding method | Dry |
| Circuit type | Closed‑circuit |
| Number of chambers | 2 |
| Liner material | High chromium steel / Rubber / Polyurethane |
| Grinding media | Forged steel / High chromium balls (Φ15–50 mm) |
| Optional features | Flash dryer, sodium activation mixer, anti‑static bag filter, water spray cooling |
When selecting a bentonite grinding mill, consider these seven factors:
Bentonite type – Sodium bentonite (high swelling) or calcium bentonite (needs activation). Measure swelling index and yield.
Raw moisture content – Below 10%: standard dry mill. Above 10%: need pre‑drying (flash dryer) or drying‑grinding mill.
Target application & fineness –
Drilling mud (API): 200 mesh (75 µm), yield >80 bbl/ton, moisture 6–10%
Foundry sand: 100–200 mesh (150–75 µm)
Pelletizing: 200 mesh with Blaine >450 m²/kg
Cat litter / absorbents: 6–20 mesh (no fine grinding)
Need for sodium activation – If your bentonite is calcium type, you must add a mixing + aging system to convert to sodium bentonite for high swelling applications.
Capacity requirement – State required tons per hour. We will match optimal bentonite ball mill capacity.
Temperature control – Ensure the system includes water spray cooling and airflow management to keep mill outlet <80°C.
After‑sales support – Installation, commissioning, training, and spare parts. Our team provides 24/7 support.
Bentonite grinding is unique because the product’s swelling capacity is more important than particle size alone. Here is what you must know.
| Grinding Condition | Effect on Swelling |
|---|---|
| Ideal (closed‑circuit, T<80°C) | High yield, good rheology |
| Over‑grinding | Fines break lattice edges, reduced swelling |
| High temperature (>120°C) | Dehydration of interlayer water, permanent damage |
| Open circuit | Wide PSD, over‑grinding common |
| Parameter | API 13A Specification |
|---|---|
| Yield (bbl/ton) | ≥80 (typically 90–110) |
| 200 mesh residue | ≤4% |
| Moisture | ≤10% |
| Viscosity (600 rpm) | ≥30 cP |
| Filtration (API) | ≤15 cm³ |
Our system consistently meets or exceeds these values when used with proper sodium activation.
| Bentonite Type | Swelling Yield (bbl/ton) | Need Activation? |
|---|---|---|
| Natural sodium bentonite | 90–120 | No |
| Natural calcium bentonite | 15–30 | Yes |
| Activated calcium bentonite (2–5% soda ash) | 80–110 | Yes |
Our activation system:
Mixer (pugmill or ribbon blender) – mixes bentonite with soda ash and water (30–35% moisture)
Aging pad or silo – 24–72 hours curing
Dryer – reduces moisture to <10% before grinding
| Problem | Our Solution |
|---|---|
| Bentonite sticks to mill liners | Rubber/polyurethane liners, polished steel |
| Media packing (balls stick together) | Small media (Φ15–40 mm), air sweep |
| Bag filter blinding | Anti‑static filter bags (for dry bentonite) |
| Feed chute blockage | Vibrating feeder + heated hopper (optional) |
Pro tip: If you are producing bentonite for drilling mud, never grind without temperature control. Even 10 minutes of overheating can permanently reduce yield by 30–50%. Our water spray cooling system maintains mill temperature below 80°C even in continuous operation. For calcium bentonite, sodium activation before grinding is essential – skip this step and your product will fail API tests.
ISO9001 & CE certified – Strict quality control from raw material to final assembly.
20+ years in clay grinding – Specialized in bentonite ball mills for drilling mud, foundry, and pelletizing.
Structure‑preserving design – Closed‑circuit, low temperature (<80°C), low‑impact grinding.
Anti‑sticking technology – Rubber/polyurethane liners, air sweep, polished surfaces.
Sodium activation integrated – Complete systems for converting calcium bentonite to API‑grade sodium bentonite.
Drying‑grinding options – Flash dryer or hot gas mill for high‑moisture feed.
Full process support – Lab test (swelling yield, viscosity, PSD) → engineering → manufacturing → installation → commissioning → training.
Global service network – Engineers available for on‑site visit and 24/7 remote troubleshooting.
Kolev Equipment Technology Co., Ltd. is a large-scale private technology enterprise specializing in the research, development, production, and sales of mining and metal ore processing equipment. With over 20 years of experience in ultra-fine grinding, industrial drying, and crushing sand making industries, we provide intelligent solutions and mature supporting products worldwide.
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