Glycine–Thiosulfate Leaching: A Mercury- and Cyanide-Free Gold Extraction Method

A Review and Sustainable Alternative to Sodium-Based and Cyanide-Containing Gold Leaching Agents - Glycine – Thiosulfate Hybrid System.

Published: Sustainable Technology eJournal November 2025. 

This study reviews the use of sodium-based compounds such as urea, sodium sulfate, sodium chloride, sodium carbonate, and thiosulfate-often formulated with sodium cyanide-as gold leaching agents by artisanal miners, and proposes a greener, more sustainable alternative.

This research further advances sustainable hydrometallurgy by developing and validating a glycine–thiosulfate hybrid leaching system as a non-toxic, cyanide- and mercury-free alternative for gold extraction.

Glycine–thiosulfate systems can yield 70–90% gold recovery under optimized lab conditions. Effectiveness is ore-dependent (best for oxide and mildly refractory ores).

Full references and supporting research are provided in the complete article: A Review and Sustainable Alternative to Sodium-Based and Cyanide-Containing Gold Leaching Agents - Glycine – Thiosulfate Hybrid System →

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Topics: chemistry, low-toxicity extraction, mercury-free gold recovery, sustainable mining.