Reaction chemistry of gold leaching in thiourea solution for a Turkish gold ore

2002 ◽  
Vol 67 (1-3) ◽  
pp. 71-77 ◽  
Author(s):  
S Örgül ◽  
Ü Atalay
Keyword(s):  
Gold Leaching ◽  
Gold Ore ◽  
Thiourea Solution

Optimization of efficient stable reagent of alkaline thiourea solution for gold leaching

2003 ◽  
Vol 10 (4) ◽  
pp. 292-296 ◽  
Author(s):  
Yun-yan Wang ◽  
Li-yuan Chai ◽  
Xiao-bo Min ◽  
De-wen He ◽  
Bing Peng
Keyword(s):  
Gold Leaching ◽  
Alkaline Thiourea ◽  
Thiourea Solution ◽  
Stable Reagent

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.

Fast and Effective Gold Leaching from a Desulfurized Gold Ore Using Acidic Sodium Chlorate Solution at Low Temperature

2013 ◽  
Vol 52 (47) ◽  
pp. 16622-16629 ◽  
Author(s):  
Yao Cheng ◽  
Shaobo Shen ◽  
Jiantao Zhang ◽  
Shuai Chen ◽  
Lei Xiong ◽  
...  
Keyword(s):  
Low Temperature ◽  
Sodium Chlorate ◽  
Gold Leaching ◽  
Gold Ore

Biooxidation of a Refractory Gold Ore: Implications of Whole-Ore Heap Biooxidation

2017 ◽  
Vol 262 ◽  
pp. 65-69 ◽  
Author(s):  
Bo Wei Chen ◽  
Jian Zhi Sun ◽  
He Shang ◽  
Biao Wu ◽  
Jian Kang Wen
Keyword(s):  
Pulp Density ◽  
Tianshan Mountain ◽  
Gold Mine ◽  
Gold Extraction ◽  
Gold Leaching ◽  
Gold Ore ◽  
Refractory Gold ◽  
Gold Reserve ◽  
Initial Ph ◽  
South Tianshan

The Sawayardun Gold Mine, the first Muruntau type gold mine in China, was located in the south Tianshan Mountain, Xinjiang Province. The gold reserve was 127 t with an average gold grade of 2.36 g/t. Due to the high content of arsenic and antimony, the traditional flotation-roasting-cyanidation process was not suitable. The direct cyanidation gold extraction for the raw ore was 44.70 %. Thus, biooxidation experiments in shaker flasks were conducted for this ore. The optimum conditions were obtained as inoculation volume 10 %, initial pH 1.7, pulp density 15 %, temperature 33 °C, leaching time 10 days, with the arsenic oxidation rate of 75.12 %. Then the biooxidation residues were test for gold leaching using NaCN, green gold leaching agent and thiourea. After 24 h leaching rate at pulp density of 33%, gold leaching agent dosage of 2 kg/t ore, the gold extraction for NaCN, green gold leaching agent and thiourea were 91.50 %, 86.23 % and 91.09 %, respectively. The high gold extraction showed a bright future for the whole-ore heap biooxidation of this refractory gold ore.

Research status and prospect of gold leaching in alkaline thiourea solution

2006 ◽  
Vol 19 (13) ◽  
pp. 1301-1306 ◽  
Author(s):  
Su Zheng ◽  
Yun-yan Wang ◽  
Li-yuan Chai
Keyword(s):  
Gold Leaching ◽  
Research Status ◽  
Alkaline Thiourea ◽  
Thiourea Solution

Gold Leaching in an Alkaline Thiourea Solution

1999 ◽  
Vol 146 (2) ◽  
pp. 559-563 ◽  
Author(s):  
Dawei Wei ◽  
Liyuan Chai ◽  
Ryoichi Ichino ◽  
Masazumi Okido
Keyword(s):  
Gold Leaching ◽  
Alkaline Thiourea ◽  
Thiourea Solution

scholarly journals Effect of Initial Cell Concentration on Bio-Oxidation of Pyrite before Gold Cyanidation

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 834
Author(s):  
Ka Yu Cheng ◽  
Caroline C. Rubina Rubina Acuña ◽  
Naomi J. Boxall ◽  
Jian Li ◽  
David Collinson ◽  
...  
Keyword(s):  
Performance Enhancement ◽  
Cell Concentration ◽  
Pyrite Oxidation ◽  
Pulp Density ◽  
Initial Cell Concentration ◽  
Gold Leaching ◽  
Initial Cell ◽  
Gold Ore ◽  
Commercial Scale ◽  
Pre Treatment

Bio-oxidation of refractory sulfidic gold minerals has been applied at the commercial scale as a pre-treatment to improve gold yields and reduce chemical consumption during gold cyanidation. In this study, the effect of initial cell concentration on the oxidation of pyritic gold ore was evaluated with four aerated bioreactors at 30 °C with 10% pulp density and pH maintained at 1.4 with NaOH. Results of NaOH consumption and changes in soluble Fe and S concentrations indicated that increasing the initial cell concentration from 2.3 × 107 to 2.3 × 1010 cells mL−1 enhanced pyrite oxidation during the first week. However, by day 18 the reactor with the lowest initial cell concentration showed profound performance enhancement based on soluble Fe and S concentrations, sulfide-S and pyrite contents in the residues, and subsequent gold leaching of the bio-oxidation residues by cyanidation. Overall, the results showed that the cell concentration was clearly beneficial during the initial stages of oxidation (first 7–8 days).

scholarly journals Consideration of Influential Factors on Bioleaching of Gold Ore Using Iodide-Oxidizing Bacteria

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 274 ◽  
Author(s):  
San Yee Khaing ◽  
Yuichi Sugai ◽  
Kyuro Sasaki ◽  
Myo Min Tun
Keyword(s):  
Potassium Iodide ◽  
Bacterial Cell ◽  
Cell Number ◽  
Culture Solution ◽  
Gold Dissolution ◽  
Marine Broth ◽  
Gold Leaching ◽  
Temperature Range ◽  
Gold Ore ◽  
Bacterial Cell Number

Iodide-oxidizing bacteria (IOB) oxidize iodide into iodine and triiodide which can be utilized for gold dissolution. IOB can be therefore useful for gold leaching. This study examined the impact of incubation conditions such as concentration of the nutrient and iodide, initial bacterial cell number, incubation temperature, and shaking condition on the performance of the gold dissolution through the experiments incubating IOB in the culture medium containing the marine broth, potassium iodide and gold ore. The minimum necessary concentration of marine broth and potassium iodide for the complete gold dissolution were determined to be 18.7 g/L and 10.9 g/L respectively. The initial bacterial cell number had no effect on gold dissolution when it was 1 × 104 cells/mL or higher. Gold leaching with IOB should be operated under a temperature range of 30–35 °C, which was the optimal temperature range for IOB. The bacterial growth rate under shaking conditions was three times faster than that under static conditions. Shaking incubation effectively shortened the contact time compared to the static incubation. According to the pH and redox potential of the culture solution, the stable gold complex in the culture solution of this study could be designated as gold (I) diiodide.

Biooxidation Pretreatment Cyanide Leaching of a Flotation Gold Concentrate

2012 ◽  
Vol 581-582 ◽  
pp. 1106-1109
Author(s):  
Chao Zhu ◽  
Bao Liang Ge ◽  
Zhao Yi Lu ◽  
Wen Zhu
Keyword(s):  
Leaching Test ◽  
Leaching Rate ◽  
Cyanide Leaching ◽  
Gold Leaching ◽  
Flotation Concentrate ◽  
Gold Ore ◽  
Leaching Process ◽  
Direct Leaching

This study reached a gold ore which contain 3.83g/t gold, to investigate the available gold recover methods, direct cyanide leaching test and “biooxidation-cyanide” leaching process were utilized after enrich gold by flotation. When regrinding the flotation concentrate to 95% -325mm, the leaching rate of “biooxidation-cyanide” leaching reached 94.47%, compare with direct leaching, the leaching rate increased almost 67%. Obviously bacterium oxidation is a useful pretreatment for gold leaching.

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