Open AccessGold Leaching from an Oxide Ore Using Thiocyanate as a Lixiviant: Process Optimization and Kinetics
Author(s) -
Atefeh Azizitorghabeh,
Harshit Mahandra,
J. O. Ramsay,
Ahmad Ghahreman
Publication year - 2021
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.1c00525
Subject(s) - lixiviant , thiocyanate , leaching (pedology) , cyanide , chemistry , gold cyanidation , inorganic chemistry , metallurgy , nuclear chemistry , materials science , geology , soil science , sulfuric acid , soil water
Thiocyanate (SCN - ) is a promising alternative to cyanide as a lixiviant for gold extraction and is 1000 times less toxic than cyanide. In this study, the following leaching parameters were tested to optimize the gold recovery for the first time from an oxide ore using the response surface methodology: initial thiocyanate concentration (10-500 mM), initial Fe 3+ concentration (10-500 mM), and pulp density (10-50% w/v). The maximum gold recovery (96%) was achieved with 500 mM thiocyanate, 100 mM Fe 3+ , and 50% pulp density at 25 °C and pH = 2 for 24 h. A kinetic study on the optimum leaching condition showed that it followed the shrinking core model, in which the rate-controlling mechanism was the diffusion process. These results are discussed in the context of the published literature.