Grinding aids in comminution: adding suitable aids during milling typically results in which outcome(s)?

Introduction / Context:
Grinding aids (e.g., glycols, amines) are small-dose additives that alter particle–particle interactions, reduce agglomeration, and improve flow in mills. They are widely used in cement and mineral grinding.

Given Data / Assumptions:

• Appropriate dosage and compatibility with the system.
• Milling equipment operating in a regime where coating and agglomeration occur.

Concept / Approach:
By reducing surface energy effects and preventing powder coating of media and liners, grinding aids maintain an efficient impact/attrition environment. This increases mill throughput (production rate) at a given fineness or enables finer product at the same throughput by suppressing agglomeration and improving classification efficiency.

Step-by-Step Solution:
Add aid → reduced agglomeration/coating → better media motion and classification.Result 1: more tons/hour at target fineness (higher production).Result 2: or, at constant rate, finer Blaine/residue (finer product).

Verification / Alternative check:
Plant trials typically show specific energy reductions or fineness improvements at equal energy, confirming both effects depending on control strategy.

Why Other Options Are Wrong:
Claiming only one benefit understates the dual impact; "neither" contradicts extensive practice.

Common Pitfalls:
Overdosing can cause foaming or separator instability; always optimize dosage by test.

Final Answer:
both (a) & (b).