UNIT-3

What is particle size distribution and why is it important?

• Particle size distribution refers to the color of particles in a sample.

• Particle size distribution only affects the aesthetic quality of materials.

• Particle size distribution is irrelevant to material processing.

• Particle size distribution is the measurement of the sizes of particles in a sample, and it is important for determining material properties and processing behavior.

Describe the difference between crushing and grinding.

• Crushing and grinding are the same process.

• Grinding is used for breaking down large rocks into boulders.

• Crushing is the process of breaking materials into larger pieces, while grinding reduces them to a finer powder.

• Crushing involves mixing materials, while grinding separates them.

What are the common methods used for screening particles?

• Condensation

• Evaporation

• Sieving, filtration, sedimentation, and centrifugation.

• Magnetization

Tara is working on a project about size reduction equipment. She needs to list three types of size reduction equipment and their uses.

• Blenders - used for mixing liquids.

• 1. Crushers - used for breaking down large rocks. 2. Grinders - used for reducing materials to finer particles. 3. Mills - used for processing grains into powder.

How does the shape of particles affect their flow properties?

• Particle shape has no effect on flow properties.

• All particles flow the same regardless of shape.

• The shape of particles affects their flow properties by influencing packing, inter-particle interactions, and friction.

• Only particle size determines flow behavior.

Explain the concept of specific surface area in relation to particle size.

• Specific surface area increases as particle size decreases.

• Specific surface area is unrelated to particle size.

• Larger particles have a higher specific surface area.

• Specific surface area decreases as particle size increases.

What is the role of a jaw crusher in size reduction?

• To grind materials into a fine powder

• The role of a jaw crusher in size reduction is to crush large rocks into smaller, manageable sizes through compressive force.

• To separate minerals from ores

• To heat rocks for melting

Define the term 'screening efficiency' and its significance.

• Screening efficiency is the effectiveness of a screening process in identifying relevant items or individuals.

• Screening efficiency is the total number of items processed in a screening.

• Screening efficiency measures the cost-effectiveness of a screening process.

• Screening efficiency refers to the speed of a screening process.

What factors influence the choice of size reduction technique?

• Packaging materials

• Material properties, desired particle size, production capacity, energy efficiency, cost, and end-use application.

• Transportation logistics

• Temperature control methods

Describe the principle of operation of a ball mill.

• A ball mill separates materials using a series of vibrating screens.

• A ball mill grinds material by rotating a cylindrical drum with balls that impact and grind the material.

• A ball mill operates by heating materials until they melt and fuse together.

• A ball mill uses a magnetic field to levitate and crush materials.