The Proportional of Grinding Balls in Limestone Ball Mill Grinding Process

When grinding limestone in a ball mill, the proportion of steel ball diameters must be adjusted according to limestone hardness, feed size, and target fineness (50 mesh, 100 mesh, 200 mesh, 300 mesh).
The core principle is:

• Large balls: impact crushing of coarse particles.
• Medium balls: transitional crushing and preliminary grinding.
• Small balls: fine and ultrafine grinding.

Basic Parameters

Limestone properties: Mohs hardness 3–4. Closer to 4 requires stronger impact; closer to 3 emphasizes grinding.

Feed size:

• Coarse (50–100 mm): requires more large balls for crushing.
• Medium (20–50 mm).
• Fine (<20 mm): fewer large balls, more small balls.

Steel ball diameters:

• Large balls: φ90–120 mm (impact crushing).
• Medium balls: φ60–80 mm (transition + coarse grinding).
• Small balls: φ30–50 mm (fine grinding).

Target product fineness:

• 50 mesh ≈ 297 μm
• 100 mesh ≈ 150 μm
• 200 mesh ≈ 75 μm
• 300 mesh ≈ 48 μm
  → Higher mesh number = more small balls required.

Scenario-Based Adjustment

1. Target: 50 Mesh (≈297 μm, coarse product, crushing dominant)

• Coarse feed (50–100 mm), high hardness (~4):
  • Large balls 40–50% (φ100–120 mm)
  • Medium balls 30–40% (φ70–90 mm)
  • Small balls 10–20% (φ40–60 mm)
• Medium feed (20–50 mm), medium hardness (~3.5):
  • Large 30–40% (φ90–110 mm), Medium 40–50%, Small 10–20%
• Fine feed (<20 mm), low hardness (~3):
  • Large 20–30% (φ80–100 mm), Medium 50–60%, Small 10–20%

2. Target: 100 Mesh (≈150 μm, balanced crushing + grinding)

• Coarse feed (50–80 mm), high hardness:
  • Large 25–35%, Medium 40–50%, Small 20–30%
• Medium feed (20–50 mm), medium hardness:
  • Large 20–30%, Medium 35–45%, Small 30–40%
• Fine feed (<20 mm), low hardness:
  • Large 15–25%, Medium 30–40%, Small 40–50%

---

3. Target: 200 Mesh (≈75 μm, fine product, grinding dominant)

• Coarse feed (30–60 mm), high hardness:
  • Large 15–25%, Medium 30–40%, Small 40–50%
• Medium feed (10–30 mm), medium hardness:
  • Large 10–20%, Medium 25–35%, Small 50–60%
• Fine feed (<10 mm), low hardness:
  • Large 5–15%, Medium 20–30%, Small 60–70%

---

4. Target: 300 Mesh (≈48 μm, ultrafine product, grinding only)

• Coarse feed (20–50 mm), high hardness:
  • Large 10–15%, Medium 20–30%, Small 60–70%
• Medium feed (10–20 mm), medium hardness:
  • Large 5–10%, Medium 15–25%, Small 70–80%
• Fine feed (<10 mm), low hardness:
  • Large 0–5%, Medium 10–20%, Small 80–90%

Adjustment Basis

According to limestone hardness

Limestone Hardness (Mohs Hardness)	Core Adjustment Direction	Target Mesh Size and Corresponding Steel Ball Diameter Ratio (Diameter Reference: Large Ball Φ80-100mm, Medium Ball Φ50-70mm, Small Ball Φ30-40mm)
Low hardness (≤2.5, weathered limestone)	Reduce the grinding ratio (avoid over-crushing) and increase medium-ball impact	1. 50 mesh: 30% large balls + 50% medium balls + 20% small balls (medium balls dominate impact, reducing small-ball grinding) 2. 100 mesh: 20% large balls + 55% medium balls + 25% small balls 3. 200 mesh: 10% large balls + 50% medium balls + 40% small balls 4. 300 mesh: 5% large balls + 40% medium balls + 55% small balls (control the small-ball ratio to avoid excessive ultrafine powder)
Medium Hardness (3-4, normal limestone)	Balance of Impact and Grinding	1. 50-mesh: 40% large balls + 40% medium balls + 20% small balls (large balls crush coarse material, medium balls refine) 2. 100-mesh: 30% large balls + 45% medium balls + 25% small balls 3. 200-mesh: 20% large balls + 40% medium balls + 40% small balls 4. 300-mesh: 10% large balls + 30% medium balls + 60% small balls (small balls dominate grinding)
High hardness (>4.5, contains siliceous impurities)	Increases the impact ratio (enhances crushing) and reduces ball wear	1. 50 mesh: 50% large balls + 40% medium balls + 10% small balls (large balls primarily crush hard and coarse materials) 2. 100 mesh: 40% large balls + 50% medium balls + 10% small balls 3. 200 mesh: 30% large balls + 50% medium balls + 20% small balls 4. 300 mesh: 20% large balls + 50% medium balls + 30% small balls (increases medium balls to assist crushing, reducing the load on small balls)

Epic Powder

In the limestone ball mill grinding process, a proper steel ball ratio is key to ensuring efficient pulverization and energy conservation. With over 20 years of experience in ultrafine powder processing, EPIC Powder offers clients comprehensive solutions, from experimental verification to production line design, helping companies achieve higher quality and lower energy consumption while maintaining stable production capacity.