Biogenic Hydrogen Sulfide for Cyanide Regeneration in Solutions during Cupriferous Gold Ores Processing

2017 ◽  
Vol 262 ◽  
pp. 131-134
Author(s):  
Anna A. Faiberg ◽  
Aleksandra N. Mikhailova ◽  
Vladimir E. Dementiev ◽  
Sergey S. Gudkov
Keyword(s):  
Hydrogen Sulfide ◽  
Sodium Cyanide ◽  
Gold Recovery ◽  
Copper Recovery ◽  
Thermophilic Microorganisms ◽  
Copper Cyanide ◽  
Gold Ores ◽  
Hydrometallurgical Processing ◽  
Optimal Approach ◽  
Process Solutions

An optimal approach to the problem of cupriferous gold ores hydrometallurgical processing is the recycling of process solutions after copper recovery and regeneration of cyanide bound in complexes. The study focuses on the copper-cyanide solutions processing technology using biogenic hydrogen sulfide for copper recovery in the form of сhalcocite, and cyanide regeneration. The strains of anaerobic sulfidogenic thermophilic microorganisms Desulfurella acetivorans and Desulfurella Kamchatkensis were used for producing hydrogen sulfide. The studies on copper precipitation and cyanide regeneration were conducted on copper-cyanide process solutions which were obtained during cyanidation of refractory cupriferous gold-bearing flotation concentrates from one of the deposits in the South Ural (Russia). Ten cycles of "Cyanidation-Regeneration" were carried out in total. The copper recovery was 86–96 %; the cyanide regeneration obtained 96 %. On an average 8.9 kg of sodium cyanide and 4.6 kg of copper sulfide were recovered from 1 m3 of solution. The sodium cyanide consumption decreased from 25.0 kg/t to 6.0 kg/t without reducing gold recovery during the CIL (carbon-in-leach) recycling process. The gold recovery was the same 63–68 %.

scholarly journals Importance of Initial Interfacial Steps during Chalcopyrite Bioleaching by a Thermoacidophilic Archaeon

2020 ◽  
Vol 8 (7) ◽  
pp. 1009
Author(s):  
Camila Safar ◽  
Camila Castro ◽  
Edgardo Donati
Keyword(s):  
High Temperatures ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Copper Recovery ◽  
Confocal Laser ◽  
Mineral Surface ◽  
Thermophilic Microorganisms ◽  
Valuable Metals ◽  
Refractory Mineral ◽  
Biofilm Development

Studies of thermophilic microorganisms have shown that they have a considerable biotechnological potential due to their optimum growth and metabolism at high temperatures. Thermophilic archaea have unique characteristics with important biotechnological applications; many of these species could be used in bioleaching processes to recover valuable metals from mineral ores. Particularly, bioleaching at high temperatures using thermoacidophilic microorganisms can greatly improve metal solubilization from refractory mineral species such as chalcopyrite (CuFeS2), one of the most abundant and widespread copper-bearing minerals. Interfacial processes such as early cell adhesion, biofilm development, and the formation of passive layers on the mineral surface play important roles in the initial steps of bioleaching processes. The present work focused on the investigation of different bioleaching conditions using the thermoacidophilic archaeon Acidianus copahuensis DSM 29038 to elucidate which steps are pivotal during the chalcopyrite bioleaching. Fluorescent in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) were used to visualize the microorganism–mineral interaction. Results showed that up to 85% of copper recovery from chalcopyrite could be achieved using A. copahuensis. Improvements in these yields are intimately related to an early contact between cells and the mineral surface. On the other hand, surface coverage by inactivated cells as well as precipitates significantly reduced copper recoveries.

scholarly journals Bio-Oxidation of a Double Refractory Gold Ore and Investigation of Preg-Robbing of Gold from Thiourea Solution

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1216
Author(s):  
Rui Xu ◽  
Qian Li ◽  
Feiyu Meng ◽  
Yongbin Yang ◽  
Bin Xu ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Active Sites ◽  
Gold Recovery ◽  
Ftir Analysis ◽  
Gold Extraction ◽  
Gold Ores ◽  
Gold Ore ◽  
Thiourea Solution ◽  
Refractory Gold ◽  
Pure Cultures

Carbonaceous sulfidic gold ores are commonly double refractory and thus require pretreatment before gold extraction. In this paper, the capacity of pre-bio-oxidation can simultaneously decompose sulfides or deactivate carbonaceous matters (CM) from a double refractory gold ore (DRGO) using pure cultures of A. ferrooxidans or L. ferrooxidans, and a mixed culture containing A. ferrooxidans and L. ferrooxidans was investigated. The results showed that direct thiourea leaching of the as-received DRGO yielded only 28.7% gold extraction, which was due to the encapsulation of sulfides on gold and the gold adsorption of CM. After bio-oxidation, thiourea leaching of the DRGO resulted in gold extraction of over 75–80%. Moreover, bio-oxidation can effectively reduce the adsorption of carbon to gold. XRD, SEM-EDS and FTIR analysis showed that many oxygen-containing groups were introduced on the surface of DRGO during bio-oxidation, while the C=C bond was cleaved and the O–C–O and C–N bonds were degraded, causing a decrease in active sites for gold adsorption. Moreover, passivation materials such as jarosite were formed on the surface of DRGO, which might reduce the affinity of CM for gold in solutions. In addition, the cleavage of the S–S band indicated that sulfides were oxidized by bacteria. This work allows us to explain the applicability of pre-bio-oxidation for degrading both sulfides and CM and increasing gold recovery from DRGO in the thiourea system.

Influence of particle size on copper recovery from sulfide ore by the moderately thermophilic microorganisms

2019 ◽  
Vol 116 (1) ◽  
pp. 119
Author(s):  
Wen-bo Zhou ◽  
Kai Li ◽  
Yu-guang Wang ◽  
Li-juan Zhang ◽  
Hai-na Cheng ◽  
...  
Keyword(s):  
Particle Size ◽  
Xrd Analysis ◽  
Microbial Interactions ◽  
Copper Recovery ◽  
Mineral Particle ◽  
Copper Ore ◽  
Thermophilic Microorganisms ◽  
Moderately Thermophilic ◽  
Before And After ◽  
Leaching Condition

The bioleaching of copper ore by the defined moderately thermophilic consortium containing Leptospirillum ferriphilum and Acidithiobacillus caldus was carried out in the bench-scale column. Bioleaching experiments showed that the leaching rate was 25% higher than that of a conventional leaching and the acid consumption was reduced by 33% at the optimal leaching condition. Meanwhile, the effect of different particle sizes on the rate of the copper leaching was also investigated, and it was shown that the particle size affects the bioleaching rate significantly in the range of 5–25 mm, in which approximately 89.27% of copper was extracted at 5–10 mm, while only 57.08% at 15–25 mm. The results obtained by X-ray diffraction (XRD) analysis of the mineral samples before and after microbial and chemical leaching revealed that the decrease in particle size of the minerals resulted in an enhancement of complex microbial interactions. Especially for the particle size of 5–10 mm, a significant amount of elemental sulfur and jarosite formed on the surface of the mineral, while it was further confirmed that critical microbe-mineral interactions have taken place on the mineral surface. The results indicated that mineral particle size is an integral factor to improve the copper recovery from ore in heap leaching operation. This will provide a reference to the heap construction for the bioleaching.

New Technology of Base Metals Precipitation by Hydrogen Sulfide Obtained Using Desulfurella acetivorans and Desulfurella kamchatkenis

2015 ◽  
Vol 1130 ◽  
pp. 477-481 ◽  
Author(s):  
Aleksandra N. Mikhailova ◽  
A.A. Faiberg ◽  
S.S. Gudkov ◽  
V.Ye. Dementev
Keyword(s):  
Hydrogen Sulfide ◽  
Electron Donor ◽  
Iron Sulfide ◽  
New Technology ◽  
Base Metals ◽  
Total Consumption ◽  
Thermophilic Microorganisms ◽  
Selective Precipitation ◽  
Sulfide Production ◽  
Hydrogen Sulfide Production

Nowadays, efficient recovery of base metals from the solutions when processing gold ores is a topical issue. In this connection, the focus is on the use of hydrogen sulfide produced in bioreactors using sulfate-reducing (SRB) and sulfur-reducing bacteria. A new technology of biogenic hydrogen sulfide production followed by the precipitation of base metals from the solutions as sulfides was developed. The strains of anaerobic sulfidogenic thermophilic microorganisms: Desulfurellaacetrivans and DesulfurellaKamchatkensis which were obtained at S.N.Vinogradsky Institute of Microbiology RAS, Moscow were used for these tests. They have anaerobic respiration using sodium acetate as an electron donor and elemental sulfur as an electron acceptor. In order to cut costs for biogenic hydrogen sulfide production, the possibility of using acetic acid as an electron donor was studied. Scaled-up test work was conducted in a 1.5L bioreactor at the temperature of 55°C, pH of 5.0, redox of-250mV and using POX solution with the content of C2+=5700.0 mg/L, Fe2+=4890.0 mg/L and Zn2+=1200.0 mg/ L. Selective precipitation of copper (at pH of ≤0.5), zinc (pH=1.0-2.0) and iron (II) (pH≥5.5) was carried out. Recycled gas contacted with the metals solutions (in a series of reactors for the precipitation of metals) coupled with the removal of hydrosulfuric acid from the recycled gas and the recovery of metals from the solution as sulfides. The precipitate was separated from the solutions by filtering. Then the filtrate was directed to the next stage. Carbon dioxide was removed from the recycled gas by filtrating through alkaline solution. After that, about 10% of ultra high purity nitrogen was added from the balloon and the recycled gas was again directed to the bioreactor. The average hydrogen sulfide reactor throughput was 1 g/L per day of culture medium. The total consumption of hydrogen sulfide was 1.28 g/L of the process solution. Results showed that this process can selectively recover metals from POX solutions with generation of high grade copper (50%), zinc (45%) and iron sulfide (45%) concentrates.

scholarly journals Assessing possibility of technogenic raw material processing using ultra-low concentrations of sodium cyanide

2020 ◽  
Vol 24 (5) ◽  
pp. 1105-1112
Author(s):  
Anastasia Vasilkova ◽  
◽  
Alexander Byvaltsev ◽  
Olga Khmelnitskaya ◽  
Grigory Voiloshnikov ◽  
...  
Keyword(s):  
Raw Materials ◽  
Sodium Cyanide ◽  
Gold Recovery ◽  
Raw Material ◽  
Ferrous Metals ◽  
Low Concentrations ◽  
Reagent Consumption ◽  
Copper Zinc ◽  
Non Ferrous Metals ◽  
Technogenic Raw Materials

The purpose of the study is to conduct experiments in order to determine the possibility of technogenic gold-bearing raw material cyanidation using ultra-low concentrations of NaCN. Experiments are carried out on the cyanidation of three samples of technogenic raw materials of different composition. The first sample consists of pyrite cinders (Au - 1.8-2.3 g/t, Ag - 13-22 g/t, Fe - 48.52%, Cu - 0.15-0.30%, Zn - 0.3-0.6%). The second sample is represented by the aged tailings of copper-zinc flotation (sample I) with the content of Au - 0.8 g/t, Ag - 7.0 g/t, Fe - 17.2%, Cu - 0.212%, Zn - 0.207%. The next object is the copper-zinc flotation tailings of a concentration plant (sample II), with the following content of Au - 1.22 g/t, Ag - 15.2 g/t, Cu - 0.13%, Zn - 0.23%. It is recommended to use an aqueous wash from non-ferrous metals with subsequent lime treatment as a preliminary processing of pyrite cinders. Cyanidation is carried out at different consumptions of reagent: from 0.075 to 3 kg/t. The experiments have shown that gold recovery in this range of NaCN consumption varies from 42.9 to 44.2%; moreover, a decrease in the reagent consumption allows to reduce the concentration of non-ferrous metal ions in cyanidation solutions. Before cyanidation sample I has also been subjected to aqueous wash to remove acid and non-ferrous metals. NaCN consumption varies from 0.25 to 2.2 kg/t. In this case the extraction of gold amounts to 36.6-46.4%. Cyanidation of tailings (sample II) is carried out in the range of 0.15-1.2 kg/t of NaCN. Gold recovery varies from 24.1 to 30.9%. The cyanidation technology of technogenic raw materials in the field of ultra-low concentrations of sodium cyanide is promising, since it provides acceptable gold recovery under low reagent consumption. For further research in the field of development of an extraction technology of valuable components, the flotation tailings of copper-zinc production (sample II) are chosen as a promising object. It is planned to carry out semi-industrial tests, calculate technical and economic indicators and develop process regulations.

Pretreatment of Refractory Gold Ores Using Cell-Free Extracts of P. chrysosporium: A Preliminary Study

2013 ◽  
Vol 825 ◽  
pp. 427-430 ◽  
Author(s):  
Grace Ofori-Sarpong ◽  
Kwadwo Osseo-Asare ◽  
Ming Tien
Keyword(s):  
Gold Recovery ◽  
Active Components ◽  
Gold Extraction ◽  
Promising Alternative ◽  
Gold Ores ◽  
Refractory Gold Ores ◽  
In Vitro Processing ◽  
Refractory Gold

The fungus Phanerochaete chrysosporium has been proven to biotransform refractory gold ores, leading to increase in gold recovery. This transformation has been attributed to enzymes secreted by the microbe. This paper reports the findings of preliminary investigations aimed at assessing the use of hydrogen peroxide and cell-free extracts from the fungus, P. chrysosporium, to effect biotransformation of sulphidic refractory gold ores. The investigations show that the total dissolved arsenic, iron and sulphur in solution were up to 5.2 wt%, 0.9 wt% and 6.0 wt% respectively from flotation concentrate after 72 hrs of treatment. Analysis for sulphide sulphur in the residual solids of the gold concentrate indicated about 25 wt% oxidation within 24 hours of treatment. In general, cell-free decomposition of the samples did not increase beyond 24 hours of contact time, possibly due to exhaustion of the active components. Gold extraction by cyanidation increased by 24% after 24-hr treatment with the cell-free extracts. Comparatively, cell-free (in vitro) treatment recorded 66% overall gold recovery as against 61% for whole cell (in vivo) after 72 hours of treatment. These initial results indicate clearly that in vitro processing is a promising alternative to in vivo processing of refractory gold ores using P. chrysosporium.

A review of copper cyanide recovery technologies for the cyanidation of copper containing gold ores

2012 ◽  
Vol 25 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Xianwen Dai ◽  
Andrew Simons ◽  
Paul Breuer
Keyword(s):  
Copper Cyanide ◽  
Gold Ores

scholarly journals Electro-hydrometallurgical chloride process for selective gold recovery from refractory telluride gold ores: A mini-pilot study

2022 ◽  
Vol 429 ◽  
pp. 132283
Author(s):  
Ivan Korolev ◽  
Pelin Altinkaya ◽  
Mika Haapalainen ◽  
Eero Kolehmainen ◽  
Kirsi Yliniemi ◽  
...  
Keyword(s):  
Pilot Study ◽  
Gold Recovery ◽  
Gold Ores ◽  
Chloride Process

Effect of Particle Size on the Column Bioleaching of Tibet Yulong Copper Ore

2015 ◽  
Vol 1130 ◽  
pp. 375-378 ◽  
Author(s):  
Li Kai ◽  
Yu Guang Wang ◽  
Li Juan Zhang ◽  
Chen Zhu ◽  
Mao Feng ◽  
...  
Keyword(s):  
Particle Size ◽  
Acid Leaching ◽  
Copper Recovery ◽  
Copper Extraction ◽  
Particle Sizes ◽  
Control Test ◽  
Copper Ore ◽  
Thermophilic Microorganisms ◽  
Column Reactor ◽  
Moderately Thermophilic

This study aimed to investigate the effect of ore particle size on the bioleaching of Yulong copper ore in the bench-scale columns using the mixed culture of moderately thermophilic microorganisms. Bioleaching experiments were carried out on particle sizes of 5-10, 10-15 and 15-25mm in the same kind of column reactors. In the control test of acid leaching, the column reactor was charged with the middle particle size (10-15mm). The results indicated that copper extraction in the column reactor with particle size of 5-10 mm was highest among the three particle sizes. After 110-days leaching, 89% of copper was leached at 5-10 mm particle size while 57% was extracted at 15-25 mm particle size and 80% at 10-15 mm. Under the same particle size (10-15 mm), copper recovery in the column reactor with inoculation of microorganisms was 25% higher in comparison to the control test of acid leaching, while sulfuric acid consumption was 33% less than that.

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