Fineness variation between batches almost always comes from unstable feeding, classifier performance, raw material, or air-circulation system. Below is a practical, step-by-step troubleshooting guide.
1. Raw Material & Feeding (Most Common Root Cause)
- Moisture fluctuation
Wet material → agglomeration → poor grinding → coarser powder.
- Hardness / particle size variation of raw ore
- Uneven feeding rate
Feeder slip, blockage, silo bridging, inconsistent feed speed.
Check:
- Standardize raw material moisture (usually < 1%).
- Verify feeder output with belt scale / gravimetric feeder.
2. Classifier (Separator) — Directly Controls Fineness
- Unstable classifier speed (inverter fault, motor drift)
- Worn classifier blades → low classification efficiency
- Improper air volume
Too much air → overly fine; too little air → overly coarse.
Check:
- Fix classifier speed and air volume as fixed parameters.
- Inspect blade wear and rotor balance.
3. Grinding Main Unit
- Grinding roller / ball wear
Reduced crushing force → unstable fineness.
- Insufficient grinding medium
- Main motor power / load fluctuation
Check:
- Roller pressure, roller sleeve wear, grinding disc/liner condition.
- Keep stable load during operation.
4. Air & Dust Collection System
- Air leakage in pipes, cyclone, mill body
- Bag filter partial blockage
Increases system resistance → changes air velocity → fineness shifts.
- Fan performance drift
Check:
- System pressure difference (ΔP).
- Clean or replace filter bags.
5. Operation & Sampling Error
- Frequent manual parameter adjustments between shifts
- Non-representative sampling
- Particle analyzer not calibrated
Fix:
- Use fixed process recipe (one set of stable parameters).
- Calibrate particle size analyzer regularly.
Quick Priority Check (From Fastest to Most Effective)
- Classifier speed & system air volume
- Feeding rate uniformity
- Raw material moisture & hardness
- Roller/grinding medium wear
- Air leakage and bag filter blockage
