Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance

Grace Ofori-Sarpong; Ahmed-Salim Adam; Richard Komla Asamoah; Richard Kwasi Amankwah

doi:doi:10.11648/j.ijmpem.20200502.11

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Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance

Grace Ofori-Sarpong, Ahmed-Salim Adam, Richard Komla Asamoah, Richard Kwasi Amankwah

Published in International Journal of Mineral Processing and Extractive Metallurgy (Volume 5, Issue 2)

Received: 13 March 2020 Accepted: 2 April 2020 Published: 15 May 2020

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Abstract

This paper presents a study on characterisation of refractory ore, biooxidation feed and product, and cyanidation tailings with the aim of understanding the causes of excessive continuous frothing, incomplete sulphide oxidation, high reagent consumption, high cyanidation residues and low overall recovery as encountered in biooxidation of refractory ores. Techniques involving carbon and sulphur speciation, Quantitative X-Ray Diffraction (QXRD), Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) were used to characterise the ore samples, flotation concentrate (BIOX® feed), biooxidised product (BIOX® CIL Feed) and cyanidation tailings (BIOX® CIL Tails) from a biooxidation plant. The main minerals present in the ore were quartz (45%), chlorites (21%), plagioclase feldspar (13%), dolomite (5%), pyrite (2%) and mica group (2%). The flotation concentrate recorded 18% mica, and this was responsible for excessive frothing in the biooxidation circuit as confirmed by the QXRD analysis. The carry-over froth to the CIL circuit led to short-circuiting of poorly leached material into the cyanidation tailings, resulting in high cyanidation residues. Secondary refractory minerals; gypsum and jarosite, which were observed in the biooxidation product by the QXRD, have the potential to coat unreacted sulphide particles, leading to incomplete sulphide oxidation as observed here. Partially oxidised sulphides led to high consumption of reagents such as oxygen and cyanide during cyanidation. Gypsum and jarosite also encapsulated gold particles as observed in the BSED analysis. Coated gold particles had reduced access to lixiviants during the subsequent cyanidation process, leading to high leach residues. The biooxidised product (BIOX® CIL Feed) also recorded a high organic carbon content of 6.67, while analysis by BSED revealed the presence of graphitic carbon and coatings on gold surfaces; an indicator for high preg-robbing activities during cyanidation of the concentrate. Preg-robbing indices of 64.4% and 72.7% were recorded for the flotation concentrate (BIOX® feed) and BIOX^® CIL feed respectively. The overarching effect of all the observations is a decrease in overall gold recovery.

Published in	International Journal of Mineral Processing and Extractive Metallurgy (Volume 5, Issue 2)
DOI	10.11648/j.ijmpem.20200502.11
Page(s)	20-29
Creative Commons	This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited.
Copyright	Copyright © The Author(s), 2020. Published by Science Publishing Group

Keywords

Biooxidation, Refractory Gold Ore, Cyanidation, Secondary Refractory Minerals, Preg-Robbing Ores, Frothing

References

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Grace Ofori-Sarpong, Ahmed-Salim Adam, Richard Komla Asamoah, Richard Kwasi Amankwah. (2020). Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance. International Journal of Mineral Processing and Extractive Metallurgy, 5(2), 20-29. https://doi.org/10.11648/j.ijmpem.20200502.11

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ACS Style

Grace Ofori-Sarpong; Ahmed-Salim Adam; Richard Komla Asamoah; Richard Kwasi Amankwah. Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance. Int. J. Miner. Process. Extr. Metall. 2020, 5(2), 20-29. doi: 10.11648/j.ijmpem.20200502.11

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AMA Style

Grace Ofori-Sarpong, Ahmed-Salim Adam, Richard Komla Asamoah, Richard Kwasi Amankwah. Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance. Int J Miner Process Extr Metall. 2020;5(2):20-29. doi: 10.11648/j.ijmpem.20200502.11

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@article{10.11648/j.ijmpem.20200502.11,
  author = {Grace Ofori-Sarpong and Ahmed-Salim Adam and Richard Komla Asamoah and Richard Kwasi Amankwah},
  title = {Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance},
  journal = {International Journal of Mineral Processing and Extractive Metallurgy},
  volume = {5},
  number = {2},
  pages = {20-29},
  doi = {10.11648/j.ijmpem.20200502.11},
  url = {https://doi.org/10.11648/j.ijmpem.20200502.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmpem.20200502.11},
  abstract = {This paper presents a study on characterisation of refractory ore, biooxidation feed and product, and cyanidation tailings with the aim of understanding the causes of excessive continuous frothing, incomplete sulphide oxidation, high reagent consumption, high cyanidation residues and low overall recovery as encountered in biooxidation of refractory ores. Techniques involving carbon and sulphur speciation, Quantitative X-Ray Diffraction (QXRD), Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) were used to characterise the ore samples, flotation concentrate (BIOX® feed), biooxidised product (BIOX® CIL Feed) and cyanidation tailings (BIOX® CIL Tails) from a biooxidation plant. The main minerals present in the ore were quartz (45%), chlorites (21%), plagioclase feldspar (13%), dolomite (5%), pyrite (2%) and mica group (2%). The flotation concentrate recorded 18% mica, and this was responsible for excessive frothing in the biooxidation circuit as confirmed by the QXRD analysis. The carry-over froth to the CIL circuit led to short-circuiting of poorly leached material into the cyanidation tailings, resulting in high cyanidation residues. Secondary refractory minerals; gypsum and jarosite, which were observed in the biooxidation product by the QXRD, have the potential to coat unreacted sulphide particles, leading to incomplete sulphide oxidation as observed here. Partially oxidised sulphides led to high consumption of reagents such as oxygen and cyanide during cyanidation. Gypsum and jarosite also encapsulated gold particles as observed in the BSED analysis. Coated gold particles had reduced access to lixiviants during the subsequent cyanidation process, leading to high leach residues. The biooxidised product (BIOX® CIL Feed) also recorded a high organic carbon content of 6.67, while analysis by BSED revealed the presence of graphitic carbon and coatings on gold surfaces; an indicator for high preg-robbing activities during cyanidation of the concentrate. Preg-robbing indices of 64.4% and 72.7% were recorded for the flotation concentrate (BIOX® feed) and BIOX® CIL feed respectively. The overarching effect of all the observations is a decrease in overall gold recovery.},
 year = {2020}
}

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TY  - JOUR
T1  - Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance
AU  - Grace Ofori-Sarpong
AU  - Ahmed-Salim Adam
AU  - Richard Komla Asamoah
AU  - Richard Kwasi Amankwah
Y1  - 2020/05/15
PY  - 2020
N1  - https://doi.org/10.11648/j.ijmpem.20200502.11
DO  - 10.11648/j.ijmpem.20200502.11
T2  - International Journal of Mineral Processing and Extractive Metallurgy
JF  - International Journal of Mineral Processing and Extractive Metallurgy
JO  - International Journal of Mineral Processing and Extractive Metallurgy
SP  - 20
EP  - 29
PB  - Science Publishing Group
SN  - 2575-1859
UR  - https://doi.org/10.11648/j.ijmpem.20200502.11
AB  - This paper presents a study on characterisation of refractory ore, biooxidation feed and product, and cyanidation tailings with the aim of understanding the causes of excessive continuous frothing, incomplete sulphide oxidation, high reagent consumption, high cyanidation residues and low overall recovery as encountered in biooxidation of refractory ores. Techniques involving carbon and sulphur speciation, Quantitative X-Ray Diffraction (QXRD), Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) were used to characterise the ore samples, flotation concentrate (BIOX® feed), biooxidised product (BIOX® CIL Feed) and cyanidation tailings (BIOX® CIL Tails) from a biooxidation plant. The main minerals present in the ore were quartz (45%), chlorites (21%), plagioclase feldspar (13%), dolomite (5%), pyrite (2%) and mica group (2%). The flotation concentrate recorded 18% mica, and this was responsible for excessive frothing in the biooxidation circuit as confirmed by the QXRD analysis. The carry-over froth to the CIL circuit led to short-circuiting of poorly leached material into the cyanidation tailings, resulting in high cyanidation residues. Secondary refractory minerals; gypsum and jarosite, which were observed in the biooxidation product by the QXRD, have the potential to coat unreacted sulphide particles, leading to incomplete sulphide oxidation as observed here. Partially oxidised sulphides led to high consumption of reagents such as oxygen and cyanide during cyanidation. Gypsum and jarosite also encapsulated gold particles as observed in the BSED analysis. Coated gold particles had reduced access to lixiviants during the subsequent cyanidation process, leading to high leach residues. The biooxidised product (BIOX® CIL Feed) also recorded a high organic carbon content of 6.67, while analysis by BSED revealed the presence of graphitic carbon and coatings on gold surfaces; an indicator for high preg-robbing activities during cyanidation of the concentrate. Preg-robbing indices of 64.4% and 72.7% were recorded for the flotation concentrate (BIOX® feed) and BIOX® CIL feed respectively. The overarching effect of all the observations is a decrease in overall gold recovery.
VL  - 5
IS  - 2
ER  -

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Author Information

Grace Ofori-Sarpong

Department of Minerals Engineering, University of Mines and Technology, Tarkwa, Ghana
Ahmed-Salim Adam

Department of Minerals Engineering, University of Mines and Technology, Tarkwa, Ghana
Richard Komla Asamoah

Future Industries Institute, University of South Australia, Mawson Lakes, Australia
Richard Kwasi Amankwah

Department of Minerals Engineering, University of Mines and Technology, Tarkwa, Ghana

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APA Style

Grace Ofori-Sarpong, Ahmed-Salim Adam, Richard Komla Asamoah, Richard Kwasi Amankwah. (2020). Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance. International Journal of Mineral Processing and Extractive Metallurgy, 5(2), 20-29. https://doi.org/10.11648/j.ijmpem.20200502.11

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ACS Style

Grace Ofori-Sarpong; Ahmed-Salim Adam; Richard Komla Asamoah; Richard Kwasi Amankwah. Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance. Int. J. Miner. Process. Extr. Metall. 2020, 5(2), 20-29. doi: 10.11648/j.ijmpem.20200502.11

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AMA Style

Grace Ofori-Sarpong, Ahmed-Salim Adam, Richard Komla Asamoah, Richard Kwasi Amankwah. Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance. Int J Miner Process Extr Metall. 2020;5(2):20-29. doi: 10.11648/j.ijmpem.20200502.11

Copy | Download

@article{10.11648/j.ijmpem.20200502.11,
  author = {Grace Ofori-Sarpong and Ahmed-Salim Adam and Richard Komla Asamoah and Richard Kwasi Amankwah},
  title = {Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance},
  journal = {International Journal of Mineral Processing and Extractive Metallurgy},
  volume = {5},
  number = {2},
  pages = {20-29},
  doi = {10.11648/j.ijmpem.20200502.11},
  url = {https://doi.org/10.11648/j.ijmpem.20200502.11},
  eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.ijmpem.20200502.11},
  abstract = {This paper presents a study on characterisation of refractory ore, biooxidation feed and product, and cyanidation tailings with the aim of understanding the causes of excessive continuous frothing, incomplete sulphide oxidation, high reagent consumption, high cyanidation residues and low overall recovery as encountered in biooxidation of refractory ores. Techniques involving carbon and sulphur speciation, Quantitative X-Ray Diffraction (QXRD), Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) were used to characterise the ore samples, flotation concentrate (BIOX® feed), biooxidised product (BIOX® CIL Feed) and cyanidation tailings (BIOX® CIL Tails) from a biooxidation plant. The main minerals present in the ore were quartz (45%), chlorites (21%), plagioclase feldspar (13%), dolomite (5%), pyrite (2%) and mica group (2%). The flotation concentrate recorded 18% mica, and this was responsible for excessive frothing in the biooxidation circuit as confirmed by the QXRD analysis. The carry-over froth to the CIL circuit led to short-circuiting of poorly leached material into the cyanidation tailings, resulting in high cyanidation residues. Secondary refractory minerals; gypsum and jarosite, which were observed in the biooxidation product by the QXRD, have the potential to coat unreacted sulphide particles, leading to incomplete sulphide oxidation as observed here. Partially oxidised sulphides led to high consumption of reagents such as oxygen and cyanide during cyanidation. Gypsum and jarosite also encapsulated gold particles as observed in the BSED analysis. Coated gold particles had reduced access to lixiviants during the subsequent cyanidation process, leading to high leach residues. The biooxidised product (BIOX® CIL Feed) also recorded a high organic carbon content of 6.67, while analysis by BSED revealed the presence of graphitic carbon and coatings on gold surfaces; an indicator for high preg-robbing activities during cyanidation of the concentrate. Preg-robbing indices of 64.4% and 72.7% were recorded for the flotation concentrate (BIOX® feed) and BIOX® CIL feed respectively. The overarching effect of all the observations is a decrease in overall gold recovery.},
 year = {2020}
}

Copy | Download

TY  - JOUR
T1  - Characterisation of Biooxidation Feed and Products for Improved Understanding of Biooxidation and Gold Extraction Performance
AU  - Grace Ofori-Sarpong
AU  - Ahmed-Salim Adam
AU  - Richard Komla Asamoah
AU  - Richard Kwasi Amankwah
Y1  - 2020/05/15
PY  - 2020
N1  - https://doi.org/10.11648/j.ijmpem.20200502.11
DO  - 10.11648/j.ijmpem.20200502.11
T2  - International Journal of Mineral Processing and Extractive Metallurgy
JF  - International Journal of Mineral Processing and Extractive Metallurgy
JO  - International Journal of Mineral Processing and Extractive Metallurgy
SP  - 20
EP  - 29
PB  - Science Publishing Group
SN  - 2575-1859
UR  - https://doi.org/10.11648/j.ijmpem.20200502.11
AB  - This paper presents a study on characterisation of refractory ore, biooxidation feed and product, and cyanidation tailings with the aim of understanding the causes of excessive continuous frothing, incomplete sulphide oxidation, high reagent consumption, high cyanidation residues and low overall recovery as encountered in biooxidation of refractory ores. Techniques involving carbon and sulphur speciation, Quantitative X-Ray Diffraction (QXRD), Scanning Electron Microscopy (SEM) and Optical Microscopy (OM) were used to characterise the ore samples, flotation concentrate (BIOX® feed), biooxidised product (BIOX® CIL Feed) and cyanidation tailings (BIOX® CIL Tails) from a biooxidation plant. The main minerals present in the ore were quartz (45%), chlorites (21%), plagioclase feldspar (13%), dolomite (5%), pyrite (2%) and mica group (2%). The flotation concentrate recorded 18% mica, and this was responsible for excessive frothing in the biooxidation circuit as confirmed by the QXRD analysis. The carry-over froth to the CIL circuit led to short-circuiting of poorly leached material into the cyanidation tailings, resulting in high cyanidation residues. Secondary refractory minerals; gypsum and jarosite, which were observed in the biooxidation product by the QXRD, have the potential to coat unreacted sulphide particles, leading to incomplete sulphide oxidation as observed here. Partially oxidised sulphides led to high consumption of reagents such as oxygen and cyanide during cyanidation. Gypsum and jarosite also encapsulated gold particles as observed in the BSED analysis. Coated gold particles had reduced access to lixiviants during the subsequent cyanidation process, leading to high leach residues. The biooxidised product (BIOX® CIL Feed) also recorded a high organic carbon content of 6.67, while analysis by BSED revealed the presence of graphitic carbon and coatings on gold surfaces; an indicator for high preg-robbing activities during cyanidation of the concentrate. Preg-robbing indices of 64.4% and 72.7% were recorded for the flotation concentrate (BIOX® feed) and BIOX® CIL feed respectively. The overarching effect of all the observations is a decrease in overall gold recovery.
VL  - 5
IS  - 2
ER  -

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