Particle Technology Practice Flashcards

A collection of vocabulary-style flashcards covering core concepts, mechanisms, and equipment in particle technology based on lecture content.

Screen efficiency

The product of recovery and rejection.

Blinded screen

A condition where a screen is plugged or clogged with solid particles.

Intermediate material

Material that passes through one screening surface but is retained on a subsequent screening surface.

• 5 mm/ - 10 mm notation

A screen analysis notation indicating that material passes through a $10\,mm$ screen and is retained on a $5\,mm$ screen.

Mesh number

The number of holes per linear inch of a screen.

Grizzlies

A type of screen that has the maximum capacity compared to trommels, shaking, or vibrating screens.

Compression

The size reduction mechanism primarily used in jaw crushers.

Attrition

The main size reduction mechanism used in ultrafine grinders and the primary action in a fluid energy mill.

Rittinger's Law

A crushing law stating that the energy required is proportional to the new surface area created.

Wet granulation

A process in particle technology that uses a liquid binder to form particles.

Dry granulation

A process in particle technology that uses mechanical pressure to form particles.

Jet milling

A particle size reduction method specifically suited for producing fine powders with a narrow size distribution.

Hindered settling

A process where the motion of a particle is impeded by other nearby particles, occurring even if they are not actually colliding.

Sedimentation

The operation by which solids are separated from liquids due to the difference in their respective densities.

Classification

The separation of solid particles into several size fractions based upon their settling velocities in a medium.

Air elutriator

A device in which a current of air separates particles with different sedimentation velocities.

Terminal velocity

The constant velocity with which a body moves relative to a surrounding fluid when the driving forces are equal to the friction force.

Thickener

An apparatus or industrial unit in which particles settle in a liquid by gravitational or centrifugal force and are removed as a concentrated slurry.

Drag force

The force exerted by a fluid on a solid in a direction opposite to the relative motion between the particle and the fluid.

$$Re < 1$$

The range of particle Reynolds numbers for which Stokes' Law is valid.

Zeta potential

The term for the electrical potential measured at the slipping plane.

Perikinetic coagulation

Coagulation that occurs when relative particle motion is due to Brownian movement.

Orthokinetic coagulation

Coagulation that occurs when relative particle motion is caused by velocity gradients.

Incipient fluidisation

The point at which the upward velocity of fluid flow through a packed bed of uniform spheres is just enough to support the particles.

Angle of repose

A rapid method of assessing the behavior of a particulate mass by measuring its slope angle.

Cullet

Waste or scrap glass that is usually ground.

Brimstone

A common name for sulfur.

Reduction ratio

The ratio of the initial particle size to the final particle size.

Work index

The gross energy requirement for size reduction.

Critical speed

The minimum speed at which a ball mill operates where the balls are carried around the circumference rather than falling.

Aperture

The square opening between the wires of a screen.