When to wet-sieve: wet sieving is preferred when the material contains what characteristic fraction?

Introduction / Context:Sieving performance deteriorates when particles agglomerate or when near-size fines blind the apertures. Wet sieving often restores accuracy by dispersing fines and carrying them through the mesh with a liquid, usually water with dispersants.

Given Data / Assumptions:

• Product exhibits a substantial fine fraction (e.g., below ~75 μm).
• Dry sieving suffers from blinding, electrostatic adhesion, or agglomeration.
• Material is water-stable or compatible with chosen liquid.

Concept / Approach:Wet sieving reduces interparticle forces, mitigates static, and flushes fines through apertures, thus improving cut accuracy. It is most beneficial when a large very-fine fraction exists, which otherwise causes oversize retention artifacts and poor mass balance in dry tests.

Step-by-Step Solution:Identify problem: fines cause blinding/agglomeration on dry screens.Introduce liquid medium: disperses fines and transports them through mesh.Outcome: improved separation fidelity and repeatability.

Verification / Alternative check:Comparative tests typically show higher undersize recovery and reduced oversize contamination when wet sieving is applied to fine-laden samples.

Why Other Options Are Wrong:Abrasive: does not by itself dictate wet sieving.Coarse or non-sticky: dry sieving normally suffices.

Common Pitfalls:Not drying and reweighing post-sieve sample; moisture correction is required for proper mass balance.

Final Answer:large quantity of very fine