THORby CI
ProductsAir Classifier

THOR Air Classifier

A spinning cage that splits fine from coarse at a sharp cut point.

THOR air classifier wheel on its assembly stand, showing the full circle of classifying vanes
Centrifugal cut

Not a mill — a gatekeeper

A slotted wheel spins against an upward airflow. Fine particles ride the air through the slots; anything too heavy is flung back out by centrifugal force and returns for regrinding.

Mechanism
Centrifugal cut
Fineness
D97 3 – 200 µm
Capacity
0.5 – 20 t/h
Request a quoteCheck specification

Working principle

Wheel speed sets the cut point — turn it up for finer, down for coarser, while the line keeps running. Paired with any mill it sharpens the whole plant's size spec.

FEEDWHEELCOLLECT

What the material passes through

  1. 1Feed inletPowder disperses into the rising air stream
  2. 2Classifier wheelVariable-speed cage — the cut-point control
  3. 3Secondary air vanesWash misplaced fines off the coarse stream
  4. 4Fines outletOn-spec product rides the air to the cyclone
  5. 5Coarse return coneRejected oversize drops back to the mill

What is an Air Classifier?

An air classifier is an industrial dynamic dry-powder separation machine that uses aerodynamic drag and centrifugal force to separate fine particles from coarse particles.

As a specialist air-classifier supplier, THOR by CI designs these systems for a cleaner, sharper, more consistent cut point than traditional physical mesh screens — especially with fine, cohesive or highly abrasive materials down to single-digit-micron ranges. It elevates plant efficiency, narrows PSD and eliminates the physical limits of mechanical screening.

Where the classifier sets the cut

500 µm
200 µm
50 µm
10 µm
3 µm
D97 cut
CoarseSub-micron

Standalone, or built in

Run it as an independent process station, or mount it directly inside the mill — two ways to sharpen the same cut.

Stand-alone air classifier (THOR-AC Series)

An independent process station downstream of any secondary grinding mill — Ball, Pin or Hammer. Material is fed in via pneumatic conveying lines or gravity chutes. Primary advantages: highest separation yield efficiency (92%); a dedicated auxiliary intake fan precisely tunes the air-to-solid ratio; easy retrofit into existing plant lines — no change to the primary mill.

Integrated / in-mill classifier (THOR-IC Series)

Mounted directly inside the primary milling chamber — typically the upper zone of the THOR-JM Jet Mill or specialized Hammer Mills — forming a single integrated unit. Primary advantages: extremely compact plant footprint; eliminates external conveying lines and collectors between mill and classifier; instantly recirculates coarse rejects into the grinding zone — preventing over-grinding and cutting energy per ton.

Advantages & limitations

A sharper cut than any screen — provided the feed is milled and dry.

Advantages

  • Modular standalone versatility

    Integrates into any grinding circuit — Hammer, Pin or Ball — of any brand.

  • Precise cut-point control (D97)

    Adjustable wheel speed shifts the target top-cut anywhere from 3 µm to 200 µm.

  • High wear protection

    Optional alumina-ceramic, silicon-carbide or polyurethane coatings for abrasive minerals.

  • High recovery yields

    Optimized internal aerodynamics keep fines off the coarse fraction — up to 92% efficiency.

Limitations to plan for

  • Requires upstream grinding

    It separates, it doesn't reduce — a pre-milled feed is required.

  • Moisture sensitivity

    Above ~3% moisture, particles agglomerate — reducing efficiency and cut-point accuracy.

  • Cost of auxiliary fans

    High separation velocities need high-pressure exhaust fans, raising capital and power cost.

Other products

See the other four

Request a pilot run