Question

Ball mill works on the following principle

• A. Compression
• B. Cutting
• C. Attrition and impact
• D. Combustion

Hint:

In mechanical operations, when grinding or breaking material, look for principles such as attrition, impact, or compression to identify the correct mechanism.

Answer 1

The Correct Option is C

Step 1: Understanding the working principle of the ball mill.
Ball mills are used in the grinding process to reduce the size of material. The principle of working involves the combination of attrition (grinding) and impact (striking). This process efficiently breaks down the material into smaller particles.
Step 2: Analyzing the options.
(A) Compression: This is incorrect as the working of the ball mill involves more than just compression.
(B) Cutting: Cutting is not the main principle of ball mill operation. While some cutting might occur, it is not the primary mechanism.
(C) Attrition and impact: Correct — Ball mills primarily work on the principles of attrition (rubbing) and impact (collision). This combination breaks down the material efficiently.
(D) Combustion: This is incorrect as combustion is not related to the working of a ball mill.
Step 3: Conclusion.
The correct answer is (C) Attrition and impact as these are the primary forces involved in the operation of a ball mill.

Answer 2

Size-reduction equipment in pharmaceutics is generally classified by the physical mechanism it uses to break particles apart, so checking which mechanism-category the ball mill belongs to settles this question.

1. Compression: Compression-based size reduction (squeezing material between two surfaces) is characteristic of equipment like roller mills or crushers, not ball mills, which do not primarily squeeze the material between fixed surfaces.
2. Cutting: Cutting mechanisms (slicing material into pieces) are characteristic of cutter mills or knife mills, used for fibrous or tough materials - a ball mill has no blades and does not cut.
3. Attrition and impact: A ball mill is a rotating hollow cylinder partly filled with grinding balls. As the cylinder rotates, the balls are lifted and then fall (impact), while also rubbing and rolling against each other and the material (attrition). This dual action is precisely the classification used for ball mills.
4. Combustion: Combustion involves a chemical burning reaction, which has nothing to do with mechanical size reduction.

Matching the ball mill's construction to the mechanism categories confirms only one fits.

Therefore, the correct answer is Attrition and impact.