Settling-based separations: what is the term for separating particles of various sizes, shapes, and densities by allowing them to settle in a fluid?

Introduction / Context:Solid–fluid separations employ different driving forces and mechanisms. When particles settle at different velocities in a fluid, engineers can exploit these differences to separate or grade materials.

Given Data / Assumptions:

• Hindered or free settling occurs depending on solids concentration.
• Separation is based on differential settling velocities.

Concept / Approach:Classification uses fluid flow and gravity to separate particles into size (and sometimes density) fractions. Hydraulic classifiers, cyclones, and elutriators are examples. Thickening and clarification focus on concentrating a slurry or producing clear overflow, not on sharp size grading; flotation relies on surface chemistry and air attachment, not settling alone.

Step-by-Step Solution:Identify mechanism: settling-driven velocity differences.Name of process: classification.Select “classification.”

Verification / Alternative check:Cut sizes in classifiers reflect balance between settling velocity and upward fluid velocity; process design targets desired size splits accordingly.

Why Other Options Are Wrong:Froth flotation uses hydrophobicity, not settling.Thickening/clarification emphasize concentration/clarity rather than size separation into multiple fractions.

Common Pitfalls:Assuming any gravity settler is a classifier; many settlers are designed for clarification rather than controlled cut points.

Final Answer:classification