John Stewart MacArthur
The document does not contain an explicit abstract or summary section. This chapter examines the principles and mechanisms of metal leaching, with emphasis on the cyanidation of gold and silver. It reviews historical development of cyanidation and alternative lixiviants such as thiourea and ammonium polysulfide, noting that these substitutes have not been adopted commercially. The text analyzes competing mechanistic theories for gold and silver dissolution in cyanide solution, including oxygen, hydrogen, hydrogen peroxide, cyanogen, and cyanate theories, and concludes—based on thermodynamic and kinetic evidence—that an electrochemical corrosion-type mechanism involving dissolved oxygen and formation of auro‑cyanide complexes is operative. Key process variables are systematically treated: cyanide concentration, pH (hydrogen ion concentration), temperature, and oxygen concentration, with discussion of optimal ranges and inhibiting conditions. The chapter further develops a quantitative diffusion-controlled model for the dissolution rate, applying Fick’s law and boundary-layer concepts to explain the observed dependence on cyanide and oxygen concentrations.
@article{2a25d3c5-a960-4cca-b03c-e59d383f3709,
title={Leaching of Metals: Cyanidation},
author={John Stewart MacArthur},
year={2026},
language={en}
}TY - JOUR TI - Leaching of Metals: Cyanidation AU - John Stewart MacArthur PY - 2026 LA - en ER -
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