Pick the correct statement: terminology and laws in size reduction Which of the following statements is correct in standard particle technology terminology?

Introduction / Context:
Process engineers must use terminology precisely—misstating a law or confusing size reduction vs. enlargement can derail calculations and vendor communications. This question probes three areas: material flow classification (cohesive vs. non-cohesive), the proper form of grinding laws, and the definition of the Bond Work Index (W_i).

Given Data / Assumptions:

• “Plastic chips” are irregular, relatively large, and typically do not exhibit interparticle cohesion like powders.
• Kick’s law and Bond’s Work Index are as defined in standard texts.

Concept / Approach:
Non-cohesive solids are free-flowing and show little tendency to stick; chips and pellets normally qualify unless tackified. Comminution is the collective term for size reduction, not enlargement. Kick’s law relates energy per unit mass to the logarithm of size ratio, but the complete form is P/m = K * ln(D_feed/D_product), not an incomplete expression. The Bond Work Index W_i is defined with respect to 80% passing 100 micrometres (not 200 mesh ≈ 74 µm) from an infinite feed size in the standard test context; thus, stating 200 mesh is inaccurate.

Step-by-Step Solution:

Verification / Alternative check:
Handbooks define W_i with P80 = 100 µm in the Bond ball mill work index test. Kick’s law explicitly uses ln(L1/L2) or ln(D1/D2), a ratio, not a single size term.

Why Other Options Are Wrong:

• (b) Missing the ratio of feed to product size.
• (c) Reverses the meaning of comminution.
• (d) Uses the wrong reference size for W_i.

Common Pitfalls:
Memorizing fragments of laws without the full functional form; always include both feed and product sizes in Kick’s correlation.

Final Answer:
Plastic chips are considered non-cohesive solids (generally free-flowing).