A fluid energy (jet) mill is primarily used for which level of grinding service?

Introduction / Context:
Jet mills accelerate particles in gas streams to achieve very fine size reduction through interparticle collisions. They are chosen when contamination must be minimal and extremely fine sizes are needed.

Given Data / Assumptions:

• No mechanical media or moving grinding parts.
• High gas velocities.

Concept / Approach:
The operating regime and achieved sizes place jet mills in the ultra grinding category. Typical outputs are in the few microm to sub-microm range with narrow size distributions, suitable for APIs, toner, and high-value pigments.

Step-by-Step Solution:
Relate mechanism (gas jets) to achievable fineness.Select “Ultra grinding”.

Why Other Options Are Wrong:
Cutting/Crushing: not applicable to jet mills.General grinding understates the capability.

Final Answer:
Ultra grinding (micron/submicron)