What Is Particle Size Distribution of ACM Mill

The ACM (Air Classifier Mill) produces a unimodal particle size distribution (PSD) with a relatively sharp top cut, thanks to its built-in dynamic air classifier. Unlike ordinary hammer mills with wide, uncontrolled PSD, the ACM continuously rejects oversize particles and sends them back to the grinding chamber for re-impact, limiting coarse tails while still containing a measurable fine fraction on the left side of the curve.

Typical PSD Index (Volume-based, laser diffraction)

Common working window for brittle minerals, battery materials, fillers:

• D10: 1–8 μm
• D50 (median size): 3–35 μm
• D97 (top-cut index): 5–150 μm

Example reference for standard mineral grinding:
D10=4 μm, D50=12 μm, D97=28 μm

When operating at the finest stable condition for soft brittle feedstock, D97 can reach ~5 μm. For coarser products, D97 can go up to 150–200 μm by lowering classifier wheel speed.

PSD Curve Characteristics

1. Sharp cutoff at the coarse end
   The rotating classifier wheel blocks large particles. This greatly reduces the number of oversized grains and creates a steep slope on the right side of the cumulative curve. This is the biggest advantage of ACM over simple screen hammer mills.
2. Has an ultrafine tail on the fine side
   Impact fracture generates a certain amount of submicron fines. Higher hammer count, higher rotor tip speed or longer particle residence time will expand this fine tail, widening PSD slightly, which matches the earlier discussion of hammer count affecting fines production.
3. Narrower PSD than standalone hammer mill, wider than jet mill

• ACM: controlled sharp top cut but inherent fine tail
• Jet mill: tighter PSD and fewer excess ultrafines at submicron range
• Ordinary hammer mill: broad PSD with many random oversize particles

Main Parameters That Reshape ACM PSD

1. Classifier wheel speed (primary control)
   Higher speed → smaller cut point, finer D50/D97; also increases proportion of fine particles.
2. Hammer count & rotor tip speed
   More hammers or higher tip speed raise impact frequency, producing more ultrafine fragments and broadening the fine tail.
3. System airflow
   Higher airflow shortens residence time; particles exit faster with less over-grinding and fewer excess fines. Low airflow keeps particles recirculating longer, adding fine fractions.
4. Feed rate and material friability
   Overfeeding makes PSD broader and D97 coarser. Soft, brittle minerals produce more fines; tough/elastic materials show less fine tail and harder to reach fine PSD.

JACAN ACM PSD Feature

JACAN ACM series delivers repeatable unimodal PSD with adjustable sharp top-cut. Ceramic-lined grinding rotors prevent iron contamination, keeping PSD consistent for high-purity battery raw materials and mineral fillers. Operators can tune classifier speed online, while hammer count is an offline mechanical modification used to adjust the baseline fine fraction of the PSD curve.

ACM mill generates unimodal PSD with a well-controlled coarse top cut and a variable ultrafine tail. D50 normally ranges from 3–35 μm and D97 from 5–150 μm. The width of PSD and amount of fine tail are governed by classifier speed, hammer configuration, rotor tip speed, airflow and material properties.