Question

Arrange the following equipment in decreasing order of the average particle size produced by each of them.

• A. ball mill, fluid energy mill, jaw crusher
• B. fluid energy mill, ball mill, jaw crusher
• C. jaw crusher, ball mill, fluid energy mill
• D. fluid energy mill, jaw crusher, ball mill

Hint:

Remember the typical sizing ranges:
Crushers: mm to cm range.
Grinders (Ball mills): micron range.
Ultrafine grinders (Fluid energy mills): sub-micron to low-micron range.
This classification makes sequencing problems straightforward.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question requires us to rank size reduction equipment based on the product particle size they generate, ordering them from the largest produced average size to the smallest.
This falls under equipment classification in mechanical operations.

Step 2: Key Formula or Approach: Size-reduction equipment is classified into four main groups based on the size of the feed they accept and the product they yield:
1. Crushers (coarse and fine)
2. Grinders (intermediate and fine)
3. Ultrafine grinders
4. Cutting machines

Step 3: Detailed Explanation:

• Jaw Crusher: This is a primary, coarse crusher.
It takes large rocks/feed (up to several meters) and crushes them into intermediate sizes, typically yielding products in the range of \( 10 \text{ to } 50 \text{ mm} \).
Thus, it produces the largest average particle size among the listed devices.

• Ball Mill: This is an intermediate/fine grinder.
It uses tumbling steel balls to grind feed of size \( 5 \text{ to } 10 \text{ mm} \) down to very fine powder, typically in the range of \( 10 \text{ to } 100 \text{ microns} \).

• Fluid Energy Mill: This is an ultrafine grinder.
It utilizes high-velocity fluid jets to cause high-speed collisions between particles.
It is used to produce extremely fine materials, often yielding average product sizes in the sub-micron to \( 1 \text{ to } 10 \text{ microns} \) range.


Step 4: Final Answer:
The correct decreasing order of average particle size produced is: Jaw crusher \( \gt \) Ball mill \( \gt \) Fluid energy mill.