Question

The grinding the final particle size to be one for which 80% of the product passes through 100 microns size sieves is stated by

• A. Fick's Law
• B. Kick's Law
• C. Rittinger's Law
• D. Bond's Law

Hint:

Remember the applicable ranges for grinding laws:
- Kick's Law: Coarse grinding (particle size \({>}50\text{ mm}\)).
- Bond's Law: Intermediate/Fine grinding (particle size \(10\ \mu\text{m to }50\text{ mm}\)).
- Rittinger's Law: Ultra-fine grinding (particle size \({<}10\ \mu\text{m}\)).

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Size reduction of solid foods (grinding and milling) requires mechanical energy.
Three empirical laws—Rittinger's, Kick's, and Bond's laws—relate the energy required for grinding to the changes in particle size.

Step 2: Detailed Explanation:
- Bond's Law (and his work index) assumes that the energy required to reduce the size of particles is proportional to the square root of the surface-to-volume ratio of the product.
- Bond defined the representative product size (\(D_p\)) as the sieve opening size through which \(80\%\) of the product passes (usually specified in microns).
This \(80\%\) passing criterion is the standard basis for all Bond's work index calculations in industrial milling.

Step 3: Final Answer:
This specific particle size criterion is stated by Bond's Law, which corresponds to option (D).