Thiosulfate Leaching of Middle-Refractory Gold Ore with Ferricyanide as Oxidant

2012 ◽  
Vol 548 ◽  
pp. 309-314
Author(s):  
Fu Ting Zi ◽  
Xian Zhi Hu ◽  
Wen Bin Zhang ◽  
Su Qiong He
Keyword(s):  
Dissolution Rate ◽  
Iron Hydroxide ◽  
Pure Gold ◽  
Gold Dissolution ◽  
Gold Ore ◽  
Base Solution ◽  
High Dissolution Rate ◽  
Refractory Gold ◽  
The Stability ◽  
Thiosulfate Leaching

In order to decrease the consumption of lixiviant, study on dissolution of pure gold and middle-refractory gold ore using a novel thiosulfate leaching system with ferricyanide as oxidant was carried out. The results showed that the advantage of the novel system is that the thiosulfate consumption is negligible though the potential of ferricyanide is much higher than that of traditional cupric ammine complex. And compared to the ferric oxalate system, novel system could be used at relatively high pH condition which benefit to the stability of thiosulfate because ferricyanide can’t transfer to iron hydroxide in base solution. It is unlikely that very high dissolution rate of gold can be obtained using an air saturated thiosulfate- ferricyanide system without thiourea catalyst. However gold dissolution rate was increased with the increasing of concentration of ferricyanid in 5 mmol/L to 30mmol/L. When 0.1mmol/L thiourea was presented, the dissolution of gold approximately 1.5 times faster than that of in the absence of thiourea. Leaching of middle-refractory gold ore show that both of the consumption of thiosulfate and leaching rate was decreased compare to the traditional copper–ammonia thiosulfate system. Thiourea is not stable in base solution, but it was found that gold dissolution rates can be increased with a little thiourea ,the mechanism is still unclear.

scholarly journals Flotation of Carbonaceous Matter from a Double Refractory Gold Ore: The Effect of MIBC on Flotation Performance and Kinetics

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1021
Author(s):  
Sugyeong Lee ◽  
Charlotte E. Gibson ◽  
Ahmad Ghahreman
Keyword(s):  
Bubble Size ◽  
Gold Recovery ◽  
Carbonaceous Matter ◽  
Flotation Kinetics ◽  
Pressure Oxidation ◽  
Gold Ore ◽  
Refractory Gold ◽  
Flotation Performance ◽  
Thiosulfate Leaching

The use of alkaline pressure oxidation to pretreat refractory gold ore often results in insufficient gold recovery (<60%) in downstream thiosulfate leaching. To improve gold recovery, flotation was considered for the separation of carbonaceous matter (C-matter). In this study, the effect of MIBC on C-matter flotation was investigated to understand the role of the frother in bubble and froth formation and on flotation kinetics. MIBC dosages between 30 and 150 g/t were used in combination with 500 g/t of kerosene as a collector. The results showed that the recovery and selectivity of C-matter were improved with increasing MIBC dosages. Improved selectivity at higher MIBC dosages was attributed to faster C-matter recovery as bubble size decreased to the critical coalescence concentration (CCC) and to changes to the foam structure. Analysis of flotation kinetics showed that the flotation rate increased as the MIBC dosage increased due to the decreasing bubble size and the reduced induction time caused by the interaction between the collector and the frother. The results of this study explain the role of MIBC in C-matter flotation and can be used as a design basis for scavenger-cleaner flotation testing. Overall, the results show the potential for flotation as a means to improve gold recovery in thiosulfate leaching through the removal of C-matter.

scholarly journals An electrochemical method to investigate the effects of compound composition on gold dissolution in thiosulfate solution

2020 ◽  
Vol 9 (1) ◽  
pp. 496-502 ◽  
Author(s):  
Zhaohui Zhang ◽  
Bailong Liu ◽  
Mei Wu ◽  
Longxin Sun
Keyword(s):  
Dissolution Rate ◽  
Current Density ◽  
Polarization Resistance ◽  
Electrochemical Method ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Corrosion Current ◽  
Gold Dissolution ◽  
Tafel Polarization ◽  
Edta Solution

AbstractThe electrochemical behavior of gold dissolution in the Cu2+–NH3–S2O32−–EDTA solution has been investigated in detail by deriving and analyzing the Tafel polarization curve, as this method is currently widely implemented for the electrode corrosion analysis. The dissolution rate of gold in Cu2+–NH3–S2O32−–EDTA solution was determined based on the Tafel polarization curves, and the effects of various compound compositions in a Cu2+–NH3–S2O32−–EDTA mixture on the corrosion potential and corrosion current density were analyzed. The results showed that the corrosion potential and polarization resistance decreased, whereas the corrosion current density increased for certain concentrations of S2O32−–NH3–Cu2+ and EDTA, indicating that the dissolution rate of gold had changed. The reason for promoting the dissolution of gold is also discussed.

Arsenic release through refractory gold ore processing. Immobilization and decontamination approaches

2021 ◽  
Vol 20 ◽  
pp. 100236
Author(s):  
Michail Samouhos ◽  
Antoniοs Peppas ◽  
Georgios Bartzas ◽  
Maria Taxiarchou ◽  
Petros E. Tsakiridis
Keyword(s):  
Gold Ore ◽  
Ore Processing ◽  
Refractory Gold

Recovery of gold from sulfide refractory gold ore: Oxidation roasting pretreatment and gold extraction

2021 ◽  
Vol 164 ◽  
pp. 106822
Author(s):  
Hong Qin ◽  
Xueyi Guo ◽  
Qinghua Tian ◽  
Dawei Yu ◽  
Lei Zhang
Keyword(s):  
Gold Extraction ◽  
Gold Ore ◽  
Refractory Gold

Manufacture of Non-Toxic Lava from Recovery of the Incineration Ash by Plasma Fusing Technology

2011 ◽  
Vol 194-196 ◽  
pp. 2365-2375
Author(s):  
Jai Houng Leu ◽  
Li Fong Wu ◽  
Ay Su
Keyword(s):  
Heavy Metals ◽  
Fly Ash ◽  
Dissolution Rate ◽  
Bottom Ash ◽  
Reduction Ratio ◽  
National Standards ◽  
Toxic Heavy Metals ◽  
Mixture Ratio ◽  
Sustainable Operation ◽  
The Stability

This research investigated and explored the overall technical and legal suggestions on mixed ash (bottom ash + fly ash) from the first BOT(built-operation then transfer) incineration plant in south Taoyuan of Taiwan, with the hope of serving as the reference for treating ash from urban refuse incinerator and making sustainable operation management policies in Taiwan. Both bottom ash and fly ash contain high-content harmful metals like lead, chrome, and cadmium, with the lead content exceeding standard value. Plasma fusing technology may effectively settle toxic heavy metals and reduce their dissolution rate. The results show that the increase in percentage of bottom ash could maintain post-fusing strength and produce solidification effect, but this reduced the stability of toxic heavy metals and raised their dissolution rate. Suitable mixture ratio of bottom ash and fly ash was 2:1, volume reduction ratio 0.349, and weight reduction ratio 0.4936. The mixture was fulvous and dense with gloss and adequate strength. The dissolution test of lava products complied with national standards, and they might be used for recycling aggregates and solidifying cement.

scholarly journals Long-Term Cytotoxicity, pH and Dissolution Rate of AH Plus and MTA Fillapex

2016 ◽  
Vol 27 (4) ◽  
pp. 419-423 ◽  
Author(s):  
Emmanuel João Nogueira Leal da Silva ◽  
Thais Accorsi-Mendonça ◽  
Ana Carolina Pedrosa ◽  
José Mauro Granjeiro ◽  
Alexandre A. Zaia
Keyword(s):  
Dissolution Rate ◽  
Experimental Period ◽  
Cell Viability Assay ◽  
Time Points ◽  
Viability Assay ◽  
Significant Difference ◽  
High Dissolution Rate ◽  
Post Test ◽  
Ah Plus

Abstract The aim of the present study was to verify the long-term cytotoxic effects of the MTA Fillapex and to compare them with AH Plus. Dissolution rate and pH were also evaluated. Human osteoblast cells were incubated with elutes of fresh specimens from AH Plus and MTA Fillapex, and with elutes of the same specimens for 4 successive weeks. Elute's pH was evaluated at each time point. A multiparametric cell viability assay was performed. For dissolution rate, ISO methodology was used. The results were analyzed by one-way analysis of variance, complemented with the Tukey post-test (p<0.05). No significant difference was found among the materials when fresh mixed (p>0.05). After 1 week, AH Plus became non-cytotoxic on all three evaluated parameters. Conversely, MTA Fillapex remained severely and mildly cytotoxic over the entire experimental period (p<0.05). The dissolution rate of AH Plus was significantly lower than MTA Fillapex at all time points (p>0.05). The pH of AH Plus was significantly lower than MTA Fillapex at the second and third week (p<0.05). In the other tested time points no statistical difference was observed. In conclusion, MTA Fillapex remained cytotoxic after 4 weeks and its cytotoxicity may be related to the high dissolution rate of this material.

scholarly journals Thermodymanic Considerations on Gold Dissolution in Different Lixiviants (I)

2019 ◽  
Vol 70 (8) ◽  
pp. 2727-2732
Author(s):  
Catalin Alexandru Barbu ◽  
Ion Constantin ◽  
Mihnea Cosmin Costoiu ◽  
Mihai Buzatu ◽  
Augustin Semenescu
Keyword(s):  
Stability Constants ◽  
Thermodynamic Stability ◽  
Gold Dissolution ◽  
Gold Complexes ◽  
Electrode Potentials ◽  
Electrochemical Mechanism ◽  
The Stability ◽  
Cyanide Solutions ◽  
Gold Industry

The paper presents the main thermodynamic aspects related to gold dissolution in different lixiviants. We analyzedthe thermodynamic stability of the gold complexes with the most representative lixiviants with potential for use in the gold industry. Based on the stability constants we determined the electrode potentials of the gold dissolution reactions in variouslixiviants and we presented the electrochemical mechanism of gold dissolution is alkaline cyanide solutions.

Semi-continuous biooxidation of the Chongyang refractory gold ore

1997 ◽  
Vol 10 (6) ◽  
pp. 577-583 ◽  
Author(s):  
Y. Wei ◽  
K. Zhong ◽  
E.V. Adamov ◽  
R.W. Smith
Keyword(s):  
Gold Ore ◽  
Refractory Gold
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