In mineral processing of gold ores, which concentration method is most widely used for fine liberated particles?

Introduction / Context:Gold beneficiation involves liberating valuable minerals and concentrating them before extraction (e.g., cyanidation). For finely disseminated gold associated with sulphides (e.g., pyrite, arsenopyrite), flotation is a dominant pre-concentration method.

Given Data / Assumptions:

• Fine liberated particles are present.
• Ore may contain sulphide carriers of gold.
• Objective: upgrade feed prior to downstream recovery.

Concept / Approach:Froth flotation selectively attaches hydrophobic particles to bubbles, separating them from hydrophilic gangue. It is highly effective at sizes below a few hundred microm, exactly where gravity-based devices lose efficiency due to low settling velocities. Jigging and tabling work best for coarser, high-density contrasts; elutriation is a specialized hydraulic classification step, not a primary gold concentrator for fines.

Step-by-Step Solution:Identify particle size regime: fine.Match separation principle: surface chemistry (flotation) excels for fines.Select flotation as the widely used method in modern gold concentrators.

Verification / Alternative check:Many refractory and sulphide-associated gold circuits employ bulk or selective flotation before oxidation and leach.

Why Other Options Are Wrong:Jigging/Tabling: gravity concentration loses efficiency on fine sizes.Elutriation: classification, not primary gold concentration.

Common Pitfalls:Assuming gravity always dominates because gold is dense; at fine sizes, hydrodynamics favour flotation.

Final Answer:Froth flotation