Question

Which among the following law is used for calculating energy requirement during size reduction?
(A). Bond's law
(B). Kick's law
(C). Henderson law
(D). Rittinger's law
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only.
• B. (A), (B), (C) and (D).
• C. (B), (C) and (D) only.
• D. (A) and (B) only.

Hint:

Kick's, Rittinger's, and Bond's laws are the fundamental "Big Three" size reduction laws.
Henderson's equation is strictly for thermodynamic moisture equilibrium in grains.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Size reduction involves mechanical breaking of solids into smaller fragments.
Several empirical laws relate the energy required to the change in particle size of the material.

Step 3: Detailed Explanation:
The three classical laws of size reduction are:
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Rittinger's Law (D): States that the energy required is proportional to the new surface area created. This holds best for fine grinding.
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Kick's Law (B): States that the energy is proportional to the ratio of initial to final particle sizes. This works well for coarse crushing.
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Bond's Law (A): Uses a work index to estimate energy requirements, matching intermediate milling operations.

Henderson's equation (C) is used in agricultural engineering to describe the equilibrium moisture content (EMC) of biological materials and is unrelated to size reduction.

Step 4: Final Answer:
The size reduction laws are (A), (B), and (D).