TY - JOUR
T1 - Significance of Fe contents on the surface of the gold ores in gold leaching by thiourea and ethylene thiourea
AU - Sasaki, Keiko
AU - Suyama, Ikumi
AU - Aoki, Yuji
AU - Konadu, Kojo T.
AU - Cindy,
AU - Chuaicham, Chitiphon
AU - Miki, Hajime
AU - Hirajima, Tsuyoshi
N1 - Funding Information:
The authors appreciate the financial supports of JSPS KAKENHI JP19KK0135, and JSPS International Exchange Programs JPJSBP120196505, JPJSBP120219929, and JPJSCCB20200003, which were provided to KS.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2023/1
Y1 - 2023/1
N2 - Environmentally friendly ligands, alternatives to cyanide, are desired to extract gold for the sustainable hydrometallurgy of gold. Leaching characteristics of gold were examined using thiourea (TU) and ethylene thiourea (ETU) as ligands from three types of gold ores with different Fe contents from 2.70 to 14.09 wt% under the acidic condition. The Au recovery by TU leaching reached the extractable maximum with the lowest Fe-bearing gold ore. This type of gold ore is suitable for TU/ETU leaching. The highest Fe-bearing gold ore was the most difficult to extract Au in ETU/TU leaching. There are at least two detrimental factors in TU leaching of Fe-rich gold ores, that is (i) the oxidative decomposition of TU, and (ii) complexation of TU with Fe3+, which both cause to deduce the complexation of TU with Au+. However, adding Na2SO3 improved the Au extraction from such an ore to reduce Fe3+ to Fe2+. ETU facilitated the formation of more stable complexes with Au than TU against the coexisting Fe3+. This finding is useful when considering the cyanide-free leaching of different types of gold ores.
AB - Environmentally friendly ligands, alternatives to cyanide, are desired to extract gold for the sustainable hydrometallurgy of gold. Leaching characteristics of gold were examined using thiourea (TU) and ethylene thiourea (ETU) as ligands from three types of gold ores with different Fe contents from 2.70 to 14.09 wt% under the acidic condition. The Au recovery by TU leaching reached the extractable maximum with the lowest Fe-bearing gold ore. This type of gold ore is suitable for TU/ETU leaching. The highest Fe-bearing gold ore was the most difficult to extract Au in ETU/TU leaching. There are at least two detrimental factors in TU leaching of Fe-rich gold ores, that is (i) the oxidative decomposition of TU, and (ii) complexation of TU with Fe3+, which both cause to deduce the complexation of TU with Au+. However, adding Na2SO3 improved the Au extraction from such an ore to reduce Fe3+ to Fe2+. ETU facilitated the formation of more stable complexes with Au than TU against the coexisting Fe3+. This finding is useful when considering the cyanide-free leaching of different types of gold ores.
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U2 - 10.1016/j.mineng.2022.107957
DO - 10.1016/j.mineng.2022.107957
M3 - Article
AN - SCOPUS:85145265115
SN - 0892-6875
VL - 191
JO - Minerals Engineering
JF - Minerals Engineering
M1 - 107957
ER -