Relative coarseness of products from different mills\nArrange the following equipment in decreasing order of average particle size of the product: Jaw crusher, Ball mill, Fluid energy (jet) mill.

Introduction / Context:
Equipment selection often begins with a target size range. Different comminution devices occupy characteristic ranges: primary crushers produce coarse fragments, tumbling mills produce finer powders, and jet mills produce ultrafines. Knowing the qualitative ordering avoids mismatches in flowsheets.

Given Data / Assumptions:

• Normal operation for each device: jaw crusher (primary reduction), ball mill (fine grinding), jet mill (ultrafine).
• Comparable, typical materials.

Concept / Approach:
Jaw crushers reduce large lumps to coarse fragments, typically 100–20 mm. Ball mills grind to fine powders, commonly 300–20 µm or finer in closed circuit. Fluid energy mills can achieve median sizes in the 1–10 µm range and below. Therefore, sorted by decreasing product size (coarsest to finest): jaw crusher > ball mill > fluid energy mill.

Step-by-Step Solution:

Verification / Alternative check:
Plant layouts universally place crushers upstream of mills, and jet mills only after fine grinding when ultrafine cuts are needed.

Why Other Options Are Wrong:

• Any ordering with jet mill coarser than ball/jaw is inconsistent with its ultrafine duty.

Common Pitfalls:
Forgetting that classifiers attached to ball mills can tighten size distributions but do not shift the mill into the ultrafine regime typical of jet mills.

Final Answer:
Jaw crusher, Ball mill, Fluid energy mill