Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP)
The effect of pyrite and the role of ammonium alcohol polyvinyl phosphate (AAPP) during gold leaching in ammoniacal thiosulfate solutions were investigated using pure gold foils. The results showed that pyrite catalyzed the decomposition and also significantly increased the consumption of thiosulfat...
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doaj-11b33157864b408e8cbd8903e2efd8712020-11-25T00:56:23ZengMDPI AGMetals2075-47012017-07-017727810.3390/met7070278met7070278Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP)Xiaoliang Liu0Bin Xu1Xin Min2Qian Li3Yongbin Yang4Tao Jiang5Yinghe He6Xi Zhang7School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaCollege of Science and Engineering, James Cook University, Townsville 4814, Queensland, AustraliaSchool of Minerals Processing and Bioengineering, Central South University, Changsha 410083, ChinaThe effect of pyrite and the role of ammonium alcohol polyvinyl phosphate (AAPP) during gold leaching in ammoniacal thiosulfate solutions were investigated using pure gold foils. The results showed that pyrite catalyzed the decomposition and also significantly increased the consumption of thiosulfate. This detrimental effect became more severe with increasing pyrite content. Further, the presence of pyrite also substantially slowed the gold leaching kinetics and reduced the overall gold dissolution. The reduction in gold dissolution was found to be caused primarily by the surface passivation of the gold. The negative effects of pyrite, however, can be alleviated by the addition of AAPP. Comparison of zeta potentials of pyrite with and without AAPP suggests that AAPP had adsorbed on the surface of the pyrite and weakened the catalytic effect of pyrite on the thiosulfate decomposition by blocking the contact between the pyrite and thiosulfate anions. AAPP also competed with thiosulfate anions to complex with the cupric ion at the axial coordinate sites, and thus abated the oxidation of thiosulfate by cupric ions. Moreover, the indiscriminate adsorption of AAPP on the surfaces of gold and passivation species prevented the passivation of the gold surface by surface charge and electrostatic repulsion. Therefore, AAPP effectively stabilized the thiosulfate in the solution and facilitated the gold leaching in the presence of pyrite.https://www.mdpi.com/2075-4701/7/7/278gold leachingthiosulfatepyriteadditivespassivation |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Xiaoliang Liu Bin Xu Xin Min Qian Li Yongbin Yang Tao Jiang Yinghe He Xi Zhang |
spellingShingle |
Xiaoliang Liu Bin Xu Xin Min Qian Li Yongbin Yang Tao Jiang Yinghe He Xi Zhang Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP) Metals gold leaching thiosulfate pyrite additives passivation |
author_facet |
Xiaoliang Liu Bin Xu Xin Min Qian Li Yongbin Yang Tao Jiang Yinghe He Xi Zhang |
author_sort |
Xiaoliang Liu |
title |
Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP) |
title_short |
Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP) |
title_full |
Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP) |
title_fullStr |
Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP) |
title_full_unstemmed |
Effect of Pyrite on Thiosulfate Leaching of Gold and the Role of Ammonium Alcohol Polyvinyl Phosphate (AAPP) |
title_sort |
effect of pyrite on thiosulfate leaching of gold and the role of ammonium alcohol polyvinyl phosphate (aapp) |
publisher |
MDPI AG |
series |
Metals |
issn |
2075-4701 |
publishDate |
2017-07-01 |
description |
The effect of pyrite and the role of ammonium alcohol polyvinyl phosphate (AAPP) during gold leaching in ammoniacal thiosulfate solutions were investigated using pure gold foils. The results showed that pyrite catalyzed the decomposition and also significantly increased the consumption of thiosulfate. This detrimental effect became more severe with increasing pyrite content. Further, the presence of pyrite also substantially slowed the gold leaching kinetics and reduced the overall gold dissolution. The reduction in gold dissolution was found to be caused primarily by the surface passivation of the gold. The negative effects of pyrite, however, can be alleviated by the addition of AAPP. Comparison of zeta potentials of pyrite with and without AAPP suggests that AAPP had adsorbed on the surface of the pyrite and weakened the catalytic effect of pyrite on the thiosulfate decomposition by blocking the contact between the pyrite and thiosulfate anions. AAPP also competed with thiosulfate anions to complex with the cupric ion at the axial coordinate sites, and thus abated the oxidation of thiosulfate by cupric ions. Moreover, the indiscriminate adsorption of AAPP on the surfaces of gold and passivation species prevented the passivation of the gold surface by surface charge and electrostatic repulsion. Therefore, AAPP effectively stabilized the thiosulfate in the solution and facilitated the gold leaching in the presence of pyrite. |
topic |
gold leaching thiosulfate pyrite additives passivation |
url |
https://www.mdpi.com/2075-4701/7/7/278 |
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