Occurrence modes of gold and relevant analytical methodologies

Area of Science:

• Geochemistry
• Analytical Chemistry
• Mineral Processing

Background:

• Gold chemical phase analysis is crucial for understanding gold occurrence in ores.
• It guides mineral processing by determining gold's host minerals.
• Existing methods involve sequential selective extraction using various solvents.

Purpose of the Study:

• To review current gold chemical phase analysis techniques.
• To identify challenges associated with existing methods.
• To propose future research directions for improved gold analysis.

Main Methods:

• Sequential selective extraction using solvents like iodine, cyanide, and sodium thiosulfate.
• Established methods include amalgamation-iodine leaching, thiourea-iodine leaching, bromine-iodine leaching, and cyanidation.
• Analysis focuses on quantifying free, sulfide-occluded, and silicate-occluded gold phases.

Main Results:

• Current methods rely on toxic reagents (mercury, cyanide), posing environmental risks.
• Analytical procedures are complex, and accuracy is affected by gold occurrence complexity and solvent selectivity.
• Pretreatment steps are costly and can cause pollution.

Conclusions:

• There is a need for developing green, low-toxicity leaching reagents.
• Integrating precise phase characterization with efficient pretreatment is essential.
• Future research should enhance analytical accuracy, efficiency, and environmental friendliness for refractory gold resources.