Leaching and recovery of gold from ore in cyanide-free glycine media

Altınkaya, Pelin; Wang, Zulin; Korolev, Ivan; Hamuyuni, Joseph; Haapalainen, Mika; Kolehmainen, Eero; Yliniemi, Kirsi; Lundström, Mari

doi:10.1016/j.mineng.2020.106610

Cited by 45 publications

(12 citation statements)

References 44 publications

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“…The residual silver (ca. 50 ppm) can be recovered using a recently developed electrodeposition-redox replacement (EDRR) method. ,− Moreover, the presented H 2 SO 4 process with H 2 O 2 additive can be improved even further as the PLS after silver electrowinning could be delivered to zinc hydrometallurgical process for further recovery of Mn and Zn, while H 2 SO 4 on the other hand can be regenerated through a mature Zn electrowinning process, as MnSO 4 is an essential additive for Zn electrowinning from sulfate bath. …”

Section: Results and Discussionmentioning

confidence: 99%

Recovery of High-Purity Silver from Spent Silver Oxide Batteries by Sulfuric Acid Leaching and Electrowinning

Wang

Peng

Yliniemi

et al. 2020

ACS Sustainable Chem. Eng.

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A sustainable and effective sulfuric acid-based process with the combination of facile acid leaching and electrowinning has been developed for the recovery of valuable elements from spent silver oxide batteries. Results suggest that the dissolution of elementary Ag was markedly promoted by the presence of MnO2 in the spent silver oxide batteries. Also, H2O2 was added to support an improved Mn and Ag extraction after 240 min of leaching. In the leaching step, 97% of silver and over 99% of Mn and Zn could be extracted under the optimum conditions: 1 mol/L H2SO4, a leaching temperature of 70 °C, an S/L ratio of 50 g/L, addition of 3 v/v % H2O2 at 240 min, and a total leaching time of 270 min. Ultra-pure silver (Ag w/w % ≥ 99.98%) was further recovered from the pregnant leaching solution (PLS) by potentiostatic electrowinning. Under the optimum deposition potential of −0.10 V and after 4 h of electrowinning, the silver recovery reached 98.5% with a high energy efficiency of 98.7%. Simultaneously, 5.6% Mn was recovered on the anode in the form of MnO2. Overall, these promising results suggest feasibility in the recycling of silver oxide batteries in sulfuric acid media.

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Section: Results and Discussionmentioning

confidence: 99%

Recovery of High-Purity Silver from Spent Silver Oxide Batteries by Sulfuric Acid Leaching and Electrowinning

Wang

Peng

Yliniemi

et al. 2020

ACS Sustainable Chem. Eng.

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“…Factor terms are considered statistically signi cant when p-value <0.05. Mathematical expressions for R 2 and adjusted R 2 are given in equations ( 4) and (5). RSM response curve is a second-order model with square and 2-way interactions.…”

Section: Design Of Experiments (Doe)mentioning

confidence: 99%

“…For more than a century, cyanide solution has been predominantly used as the lixiviant agent to extract gold from its ores [3]. However, the use of cyanide is associated with an environmental impact ascribed to its virulent and lethal e ects on humans, terrestrial animals, and aquatic organisms [4,5]. Moreover, gold complexation with cyanide is characterized by slow reaction kinetics and consumes large quantities of reagents in the presence of refractory sul dic and carbonaceous ores as well as copper-rich gold ores; leading to an increase in the leaching process cost thereof [6].…”

Section: Introductionmentioning

confidence: 99%

Application of Response Surface Methodology (RSM) for Simultaneous Optimization of Kinetic Parameters Affecting Gold Leaching in Thiosulfate Based Media: A Statistical Approach

Baloyi

Nseke

Makhatha

2022

Journal of Chemistry

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Over the years, the use of new alternative lixiviants for gold extraction has been investigated to overcome the environmental concerns resulting from the cyanidation process. Moreover, with global economic factors causing a decline in gold prices, it is crucial that novel hydrometallurgical methods of extracting gold minimise operational costs by using low-priced reagents such as thiosulfate. In the current study, the response surface methodology (RSM) approach is used to optimize the kinetic factors (temperature and copper, ammonia, and thiosulphate concentration) affecting gold leaching. Gold ore assayed at 16 g/t was characterized through X-ray fluorescence and X-ray diffraction spectrometric analysis as well as scanning electron microscope-energy dispersive spectrometric technique. Gold ore was predominantly siliceous with minor pyritic content. The results indicate a strong relationship between the actual gold leaching recovery data and the RSM model. Correlation coefficients R2 and adjusted R2 are equivalent to 0.9869 and 0.9817. Gold leaching in copper-ammonia-thiosulfate media is best described as a surface chemical reaction-controlled process, suggesting that gold dissolution in thiosulfate is considerably affected by the increase in temperature. The effect of temperature is mostly significant, contributing up to 64.65% of the gold recovery response model. The contribution percentages of the effects of time, thiosulfate [S2O3], ammonia [NH3], and copper [Cu] concentrations were calculated as 12.81%, 5.88%, 5.19%, and 4.65%, respectively. All investigated kinetic parameters were found statistically significant with p value <0.05. The optimal concentrations of gold leaching media to achieve potentially complete dissolution of gold from its ore in copper-ammoniacal thiosulphate media based on the effect of the investigated parameters were 0.5 M S2O3, 3 M NH3, and 0.003 M Cu2+ with a desirability value equivalent to unity (d = 1.000).

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“…Cyanide, characterised by the ─C≡N group, is one of the most lethal chemicals in nature [1][2][3][4][5][6]. Cyanide in the form of metal salts is widely used in the gold industry because of its excellent efficiency for the extraction of gold [7][8][9][10]. It also occurs naturally in more than 2,000 plant species as cyanogenic glycosides [11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Study of Cyanide Contamination of Market Garden and Agricultural Products Grown Around the Samira Gold Mine (Niger)

Hassane¹,

Mahamane²,

Adamou³

2022

AJEP

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The term cyanide refers to all the compounds producing the ─C≡N group. It comes from both anthropogenic and natural origins. Its presence in the environment is largely related to gold mining. Cyanide is very scary because of its toxicity causing very deadly environmental consequences. The objective of this work is to study the fate of cyanide and assess its contamination on the environment in the vicinity of a potential source of pollution such as a gold mine. In this study, soils and foods samples from the Samira gold mine and its surroundings in southwestern Niger were collected, analysed and compared with equivalent control samples grown in areas free of any industrial cyanide source. Total cyanide contents in the soils of the Samira site and its surroundings are 2 to 104 times higher than the Canadian standard (0.90 µg g -1 CN -) for agricultural soils, while the control soils are almost free of cyanide. These results show a migration of cyanide from the mine tailings to the surrounding area and these soils are unsuitable for any crop. The produced foods on these polluted soils have total cyanide contents 2 to 5 times higher than their controls. These contaminated matrices reveal negative impacts of the Samira mine's gold activities on its immediate environment. Ingestion of these foods would lead to serious health consequences for local populations.

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Leaching and recovery of gold from ore in cyanide-free glycine media

Cited by 45 publications

References 44 publications

Recovery of High-Purity Silver from Spent Silver Oxide Batteries by Sulfuric Acid Leaching and Electrowinning

Recovery of High-Purity Silver from Spent Silver Oxide Batteries by Sulfuric Acid Leaching and Electrowinning

Application of Response Surface Methodology (RSM) for Simultaneous Optimization of Kinetic Parameters Affecting Gold Leaching in Thiosulfate Based Media: A Statistical Approach

Study of Cyanide Contamination of Market Garden and Agricultural Products Grown Around the Samira Gold Mine (Niger)

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