Ultrafine particle sizing is most effectively characterized using___________________?
Show answer Hide answer
Answer: D. Surface area per unit mass
Explanation
Sieve screens cannot physically resolve ultrafine particles below micro-scale sieve aperture limits. Specific surface area per unit mass increases dramatically as particle dimensions decrease into the ultrafine range. Measuring total surface area provides a reliable indirect indicator of extremely fine powder fineness. Ultrafine comminution produces powders with particle sizes well below standard industrial sieve ranges. Gas adsorption methods like BET analysis measure specific surface area accurately for fine mineral powders. Surface area correlates directly with reactivity, dissolution rates, and pigment hiding power.
Cement, pigment, and pharmaceutical industries rely on specific surface area to control powder quality. Standard sieve analysis becomes impractical and inaccurate for powders finer than forty micrometers. Optimizing ultrafine grinding circuits requires reliable surface area metrics to prevent under-grinding. Option A centimeters represent macro-scale dimensions entirely unsuited for microscopic particle sizing. Option B standard screen sizes fail because physical mesh apertures cannot be manufactured small enough. Option C micron is a unit of linear dimension rather than a comprehensive characterization metric.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
Related questions
Q1. Splitting a slurry into a clear supernatant liquid and a thickened high-solid sludge is called__________________?
Show answer Hide answer
Answer: B. Sedimentation
Sedimentation involves gravity settling of suspended solids from a liquid slurry suspension. The process yields a clear supernatant liquid at the top and a thickened sludge at the bottom. Continuous thickeners utilize sl...
Q2. Dividing a liquid-suspended solid mixture into a clear overflow and a denser underflow slurry employs a process termed___________________?
Show answer Hide answer
Answer: C. Sedimentation
Sedimentation clarifies a suspension by allowing solids to settle out, producing a clear liquid overflow and a denser underflow. Gravity causes denser suspended particles to migrate downward while clear liquid remains at...
Q3. Bulk transport over short distances of materials like grain, sand, ash, and gravel is handled by a ______________ conveyor?
Show answer Hide answer
Answer: D. Screw
Screw conveyors feature a rotating helical blade operating inside a stationary tubular or U-shaped trough. They efficiently push bulk granular materials like grain and sand over short horizontal or inclined distances. Th...
Q4. Roll crushers and steam-heated rollers are employed for the size reduction of _____________?
Show answer Hide answer
Answer: C. Hard rubber
Hard rubber exhibits elastic and resilient properties that respond well to compressive rolling forces. Roll crushers and steam-heated rollers deform and reduce tough elastomeric materials without clogging. Heating the ro...
Q5. Separating solid particles according to their densities is designated as_________________?
Show answer Hide answer
Answer: B. Sorting
Sorting separates particles based on differences in their physical properties, such as density or shape, rather than just size. Particles with identical sizes can be segregated if their densities or surface properties di...
Q6. Compared to plate and frame filter presses, shell and leaf filters_____________________?
Show answer Hide answer
Answer: D. All A., B. & C.
Shell and leaf filters operate within closed pressure vessels, reducing manual labor and operator exposure. Enclosed designs safely withstand much higher operating pressure differentials than standard plate presses. Inte...