Overview

Spiral Jet Mill

A spiral jet mill is also called a pancake jet mill. The spiral jet mill is suitable for the fine and ultrafine size reduction of materials up to a Mohs hardness of 9 that display brittle crystalline grinding characteristics. They are typically used in applications where a high ultrafine portion is required.

D97<2μm

Fineness Range

0°C+

Heat-Free Process

360°

Process Support

Spiral Jet Mill

Principle

No Moving Parts, No Contamination.

Spiral Jet Mill principle diagram

Spiral Jet Mill Diagram

01

Compressed Gas Injection

High-pressure compressed air or inert gas is injected tangentially through precisely angled nozzles arranged around the grinding chamber periphery, generating a supersonic spiral vortex.

02

Particle Acceleration & Collision

The raw material is introduced into the chamber via a venturi injector. Particles are instantly entrained and accelerated by the supersonic gas stream. Grinding occurs primarily through inter-particle collision.

03

Centrifugal Classification

This stage acts as an internal sorting mechanism governed by the equilibrium between the centrifugal force and the centripetal drag force. As particles become finer, their mass decreases until the drag force overcomes the centrifugal force.

04

Collection & Recovery

Once the particles pass the internal classification "cut point," they exit through the central discharge port along with the exhausted gas. The fine powder is then conveyed to a cyclone separator or a high-efficiency bag filter.

Features

Zero Contamination

No grinding media, no rotating mechanical parts inside the chamber. Particle-on-particle impact ensures product purity -- critical for API milling, food-grade, and battery cathode materials.

Cool Grinding

As the compressed gas expands through the nozzles, it creates a cooling effect (Joule-Thomson effect) that counteracts any heat generated during impact. This makes it the ideal solution for processing heat-sensitive material.

Precise Particle Size Control

Equipped with an integrated static classification mechanism, the mill ensures a narrow particle size distribution. Achieve D50 of 1-10 μm and D97 below 20 μm with consistent batch-to-batch reproducibility.

Material Testing Available Before Purchase

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Specification

JM-SJ Spiral Jet Mill model specifications
Model Chamber Ø (mm) Capacity (kg/hr) Air Consumption (m³/min) Working Pressure (MPa)
AS50 50 0.05 - 0.5 0.6 - 0.9 0.6 - 1.0
AS100 100 0.5 - 1 1.6 - 2.0 0.6 - 1.0
AS150 150 2 - 10 2.5 - 3.5 0.6 - 1.0
AS200 200 5 - 20 4.0 - 5.0 0.8 - 1.0
AS300 300 10 - 80 6.5 - 7.0 0.8 - 1.0
AS350 350 20 - 180 7.0 - 12.0 0.8 - 1.2
AS450 450 40 - 400 10.0 - 12.0 0.8 - 1.2
AS650 650 50 - 600 20.0 - 27.0 0.8 - 1.2
AS1000 1000 500 - 2000 40.0 - 50.0 0.8 - 1.2

* Capacity values are indicative and depend on material properties, target fineness, and operating pressure.

** The specific feed size depends on the chamber size.

General Parameters

  • Achievable D97 < 2 - 20 μm
  • Feed Particle Size (max) ≤ 3 mm
  • Contact Material Stainless steel / Ceramic
  • Surface Finish (Ra) ≤ 0.4 μm
  • Gas Type Air / N₂ / Ar
  • Chamber Temperature 10 - 20 °C
  • Certifications CE / GMP / ATEX

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Applications

Pharmaceutical API milling
Pharmaceutical

API & Excipient

Ideal for micronizing active pharmaceutical ingredients (APIs) and excipients to achieve controlled particle size distributions with no contamination.

Battery cathode material micronization
Battery

Cathode & Anode

Ultra-fine milling of LFP, NCM, NCA, and graphite under inert N₂ atmosphere to prevent oxidation, ensuring electrochemical performance and consistent D50 for electrode coating uniformity.

Fine Chemical application
Chemical

Fine chemical and pigment

The absence of moving parts and mechanical heat generation ensures that heat-sensitive pigments and reactive chemical intermediates remain chemically stable during processing.

Food additive and nutraceutical micronization
Food

Nutraceuticals

Gentle, heat-free micronization of vitamins, herbal extracts, spices, and functional food ingredients -- preserving bioactivity and flavor compounds while achieving ultra-fine particle sizes.

FAQ

Answers to the most common technical and commercial questions from procurement managers and process engineers evaluating spiral jet mills.

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What particle size can a spiral jet mill achieve?
Typical product fineness ranges from d50 = 1 µm to 20 µm, with some materials reaching sub‑micron levels (d50 < 1 µm).
How is the spiral jet mill cleaned between product changeovers?

Spiral jet mills are relatively easy to clean due to their simple geometry:

  • The grinding chamber can often be opened and accessed without tools.
  • Cleaning can be done by vacuuming, blowing with compressed air, or washing.
  • Quick disassembly is possible, typically within 5–10 minutes.
How do I control the final particle size?

Key parameters:

  • Grinding pressure – higher → finer, but up to a limit.
  • Feed rate – slower feed generally provides finer product.

    • For spiral jet mills without a separate classifier, the design of the outlet vortex circle determines the cut point.

What are the limitations of a spiral jet mill？
  • Particle size distribution is less steep than fluidized bed mills
  • Not ideal for sticky, ductile, or very soft materials
  • Higher wear when processing very hard or abrasive materials