Sizing of fine materials: Which screening device is generally most suitable for fine particle separations in industrial practice?

Difficulty: Easy

Correct Answer: Vibrating screen

Explanation:


Introduction / Context:
Screening separates particles based on size using a perforated surface. The mechanical excitation method determines efficiency, capacity, and the fineness attainable without blinding.


Given Data / Assumptions:

  • Fine sizing (sub-millimeter to a few millimeters).
  • Industrial throughputs and continuous operation.
  • Typical screen media and anti-blinding aids are available.


Concept / Approach:

Vibrating screens deliver high frequency, controlled amplitude motion that stratifies the bed and clears apertures, making them ideal for fine separations. Trommels are better for coarse, sticky feeds; grizzlies for very coarse scalping; shaking screens are older technology with lower capacity and efficiency for very fine cuts.


Step-by-Step Solution:

List devices and typical cut sizes.Match fine separations with high-frequency vibration → vibrating screens.Exclude coarse-feed devices (grizzly, trommel) and lower-efficiency shaking screens for very fine cuts.


Verification / Alternative check:

Plant experience confirms multi-deck vibrating screens dominate fine screening in minerals and chemicals processing.


Why Other Options Are Wrong:

Trommel/Grizzly: Coarse scalping; poor for fines. Shaking screen: Lower capacity/efficiency at very fine apertures compared to modern vibratory designs.


Common Pitfalls:

Using trommels for fines when moisture and stickiness cause blinding; not installing vibratory aids or proper media for small apertures.


Final Answer:

Vibrating screen

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