ECS-SS Spiral Jet Mill (500 g/h), ESSSJM

A Spiral Jet Mill (also known as a Pancake or Disk-Type Jet Mill) is a high-precision, dry-grinding technology used to achieve sub-micron particle sizes. Unlike mechanical mills that use hammers or pins, the spiral jet mill relies entirely on high-velocity gas streams to cause particles to collide with each other, making it a "self-grinding" or autogenous process.

The grinding occurs inside a flat, cylindrical chamber (the "pancake"). (1) Supersonic Injection: Compressed air or inert gas (like N2) is injected through several Laval nozzles arranged tangentially around the chamber's periphery at high pressure. This creates a supersonic vortex flowing toward the center. (2) Inter-particle Collision: Raw material (pre-crushed to <1 mm) is introduced into the chamber via a Venturi feeder. The particles are caught in the vortex and collide with each other at speeds of 300–500 m/s. (3) Centrifugal Classification: This mill is its own classifier. Larger particles are thrown to the outer rim by centrifugal force to be ground further. As they become smaller and lighter, the drag force of the gas pulls them toward the central discharge port.

Working Principle Sketch for the Spiral Jet Mill:

References:

R. Malik, et al., Synthesis of layered silicon-graphene hetero-structures by wet jet milling for high capacity anodes in Li-ion batteries, International Journal of Mineral Processing, 2021 2D Mater. 8 015012

T. Tsujikawa, et al., Effect of cathode active materials produced by a wet-type jet mill on lithium cell performance, Journal of Power Sources, 2009, 192, 679-683