En
Grinding balls are the media used in ball mills to grind materials. During operation, they continuously impact and rub against the material and the mill lining, causing wear and tear. Therefore, selecting the right grinding balls requires evaluating the following 6 indicators based on specific working conditions.
Choose a material with a hardness higher than that of the material being ground. For example:
High-Chromium Cast Iron: Offers high hardness and wear resistance (wear rate ~2.2%), ideal for heavy loads and hard materials (e.g., ores). However, it is brittle and expensive.
Low-Carbon Alloy Steel: Cost-effective with good toughness, lasting over twice as long as low-chromium cast balls under similar conditions.
High-Manganese Steel: Excellent toughness; its surface hardens under impact, enhancing wear resistance.
High-Carbon High-Manganese Alloy Steel: Combines hardness and toughness, lasting over twice as long as high-manganese steel but remains brittle and costly.
Stainless Steel: Superior corrosion resistance, suitable for pharmaceuticals/food industries, but pricier.
For high-impact conditions (e.g., coarse grinding), opt for tough materials like high-manganese or low-carbon alloy steel. For high-load but low-impact grinding (e.g., fine grinding), prioritize harder but less tough materials.
Match wear resistance to material hardness and mill conditions. High-chromium and high-carbon alloy steels are highly wear-resistant.
The diameter of steel balls in ball mills ranges from 20-125mm, divided into large balls, medium balls, and small balls. However, the steel ball diameter used in ultra large ball mills can reach 130-150mm.
Coarse grinding: Use large balls (Φ100–120 mm) for impact crushing.
Fine grinding: Add medium (Φ60–80 mm) and small grinding balls (Φ40–60 mm) to increase grinding surface area.
Ratio Scheme: 30–40% large, 30–40% medium, 20–30% small balls. Adjust proportions based on material hardness. Every 300-500 hours of operation, 2% -3% of the total ball load needs to be replenished.
Select smooth, defect-free balls. Inspect visually or with non-destructive testing.
Forged Grinding Balls: Better internal quality and mechanical properties, ideal for wet grinding process.
Cast Grinding Balls: Lower cost but less durable, suitable for dry grinding process.
Choose the appropriate grinding ball for your ball mill, you can optimize grinding efficiency, extend ball mill life, and reduce costs.
