scholarly journals Leaching Behavior of Gold and Silver from Concentrated Sulfide Ore Using Ammonium Thiosulfate

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1029
Author(s):  
Mooki Bae ◽  
Sookyung Kim ◽  
Jeongsoo Sohn ◽  
Donghyo Yang ◽  
Hyunju Lee
Keyword(s):  
Liquid Ratio ◽  
Leaching Behavior ◽  
Gold Ores ◽  
Ammonium Thiosulfate ◽  
Sulfide Ore ◽  
Main Chemical Composition ◽  
Hydrometallurgical Treatment ◽  
Thiosulfate Leaching ◽  
Leaching Efficiency ◽  
Thiosulfate Concentration

Ammonium thiosulfate is an alternative lixiviant for the hydrometallurgical treatment of sulfide gold ores. The present study is primarily focused on ammonium thiosulfate leaching of gold (Au) and silver (Ag) from the sulfide ore (Sunshin mine in Korea). The main chemical composition of the concentrate was Au (84 ppm), Ag (852 ppm), Fe (18.9%), Si (23.2%), and S (21.1%). The effects of various parameters on the process, such as leaching time (1–4 h), ammonium thiosulfate concentration (0.05–0.5 M), copper sulfate (CuSO4), concentration (0.05–0.25 M), solid to liquid ratio (0.2–0.5), and reaction temperature (40–60 °C) were systematically examined. Optimum Au leaching efficiency (>99%) was obtained under the following leaching conditions: 0.5 M ammonium thiosulfate with 0.05 M CuSO4 concentration, 0.2 S/L ratio at 60 °C for 2 h. The results indicate that the behavior of Ag was similar to that of Au. Almost complete dissolution of Ag occurred under following leaching conditions: 0.5 M ammonium thiosulfate with 0.05 M CuSO4 concentration at 60 °C for 4 h. This study would be useful in understanding the eco-friendly leaching systems of Au and Ag during the hydrometallurgical process of sulfide gold ore.

scholarly journals The treatment of copper–gold ores by ammonium thiosulfate leaching

2002 ◽  
Vol 66 (1-3) ◽  
pp. 1-21 ◽  
Author(s):  
Ellen Molleman ◽  
David Dreisinger
Keyword(s):  
Gold Ores ◽  
Ammonium Thiosulfate ◽  
Copper Gold ◽  
Thiosulfate Leaching

A physical separation scheme to improve ammonium thiosulfate leaching of gold by separation of base metals in crushed mobile phones

2019 ◽  
Vol 138 ◽  
pp. 168-177 ◽  
Author(s):  
Sanghee Jeon ◽  
Mayumi Ito ◽  
Carlito Baltazar Tabelin ◽  
Rongrit Pongsumrankul ◽  
Shinya Tanaka ◽  
...  
Keyword(s):  
Mobile Phones ◽  
Separation Scheme ◽  
Base Metals ◽  
Physical Separation ◽  
Ammonium Thiosulfate ◽  
Thiosulfate Leaching

scholarly journals Leaching of hemimorphite in neutral solution at high temperature

2020 ◽  
Vol 56 (2) ◽  
pp. 203-208
Author(s):  
D.-Q. Zhao ◽  
S.-H. Yang ◽  
Y.-M. Chen ◽  
C.-B Tang ◽  
J. He ◽  
...  
Keyword(s):  
High Temperature ◽  
Silica Gel ◽  
Chloride Concentration ◽  
Stirrer Speed ◽  
Neutral Solution ◽  
Leaching Behavior ◽  
Experimental Conditions ◽  
Increasing Temperature ◽  
Optimized Conditions ◽  
Leaching Efficiency

The leaching behavior of hemimorphite in neutral solution (NH4 +-Cl--H2O) was investigated at high temperature (T > 100?C) under a range of experimental conditions. Thermodynamic calculations indicate that the tendency of dehydration of silica gel is significantly enhanced with the increasing temperature. It was shown that the temperature, ammonium chloride concentration, or L/S ratio increased resulted in greater leaching efficiency. The following optimized leaching conditions were obtained: stirrer speed 400r/min, NH4Cl concentration 5.5M, L/S ratio 9mL/g at 160?C for 3h. Under these optimized conditions, the average leaching yield of zinc was 97.82%. The silicon was converted to quartz and remained in the residue. This process can be used to dispose willemite and hemimorphite as it solves the problem of silica gel dehydration.

Gold recovery from shredder light fraction of E-waste recycling plant by flotation-ammonium thiosulfate leaching

2018 ◽  
Vol 77 ◽  
pp. 195-202 ◽  
Author(s):  
Sanghee Jeon ◽  
Mayumi Ito ◽  
Carlito Baltazar Tabelin ◽  
Rongrit Pongsumrankul ◽  
Naho Kitajima ◽  
...  
Keyword(s):  
Waste Recycling ◽  
Light Fraction ◽  
Gold Recovery ◽  
Ammonium Thiosulfate ◽  
Thiosulfate Leaching

scholarly journals Study on the Oxidative Leaching of Uranium from the Lignite in the CO32-/HCO3- System

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Y. Ning ◽  
Y. Li ◽  
Y. Zhang ◽  
P. Tang
Keyword(s):  
Yunnan Province ◽  
Reaction Model ◽  
Second Order Reaction ◽  
Liquid Ratio ◽  
Uranium Leaching ◽  
Pseudo Second Order ◽  
Oxidative Leaching ◽  
Solid Liquid ◽  
Leaching Efficiency ◽  
Alcoholic Hydroxyl

Na2CO3/NaHCO3 mixtures with different oxidants were used to leach uranium in the lignite which was obtained from Lincang, Yunnan province. The experimental results showed that the optimal solid/liquid ratio and CO32-/HCO3- ratio for uranium leaching were 1 : 20 (g/mL) and 2 : 1, respectively. With the increase of carbon concentration from 0.1 mol/L to 1.1 mol/L, the leaching efficiency of uranium increased from 14.64% to 42.39% after 6 h leaching. The oxidants could significantly enhance the uranium leaching efficiency, which was up to 72.23% by injecting O2 at 1.5 L/min after 12 h leaching. The oxidative leaching process of uranium from the lignite was better fitted to the pseudo-second-order reaction model. The sequential extraction results illustrated that the oxidants could effectively enhance the leaching of organic matter bound uranium in the lignite, which was decreased from 76.86 mg/kg to 9.00 mg/kg by injecting O2. The infrared spectrum analysis demonstrated that the corresponding transmittance at about 3197 cm−1 was prominently reduced after the oxidative leaching, which intimated that the phenolic and alcoholic hydroxyl might be the main functional groups combined with uranium in the lignite.

The Solubility of Phosphogypsum and Recovery of Heavy and Radioactive Elements

2020 ◽  
Vol 38 (10A) ◽  
pp. 1470-1480
Author(s):  
Waleed T. Rashid ◽  
Israa A. Alkadir ◽  
Moayyed G. Jalhoom
Keyword(s):  
High Mobility ◽  
Major Elements ◽  
Radioactive Elements ◽  
Liquid Ratio ◽  
Phosphate Fertilizers ◽  
Negative Effect ◽  
Temperature Ranges ◽  
Solid Liquid ◽  
Positive Effect ◽  
Leaching Efficiency

The essential purpose of this paper is to illustrate and inspect the leaching characteristics of Iraqi Phosphogypsum (PG). The paper presents the results of the dissolution characteristics of heavy and radioactive elements from PG, which is a by-product result from the industry of phosphate fertilizers. Leachability of heavy and radioactive elements in deionized water that has been inspected under various states of leaching, including solid/liquid ratio (10, 20 and 50 /1g/L) and temperatures (25, 45 and 85 °C), with constant other parameters such as string speed (300 rpm) and contact time (60 minutes). For the most analysis elements, the progressive release of the metals, in addition to the major elements reflects high mobility.  The mobility of trace metals in PG has been generally classified into three main degrees: (1) high mobility elements such as Pb, Zn, Mn, and Cr; (2) moderate mobility elements such as Sr, V, Ba,Y,Hg, K and Ni; and (3)l ow mobility elements like Ca,Cu,Fe, and Ag. The maximum concentrations of the most of the metals were attained from a leaching state of 10/1g/L. Regarding temperature, the experimental results revealed that the PG solubility to leaching out elements increases noticeably as the applied temperature ranges from 25 to 45 °C; after this degree, the leaching efficiency decreases. Chloride had a positive and negative effect on the solubility of phosphorus. Calcium chloride had an adverse effect on solubility and observed reduced solubility with increased chloride. While the positive effect of sodium and magnesium chloride was observed, the solubility...

Interference of coexisting copper and aluminum on the ammonium thiosulfate leaching of gold from printed circuit boards of waste mobile phones

2018 ◽  
Vol 81 ◽  
pp. 148-156 ◽  
Author(s):  
Sanghee Jeon ◽  
Carlito Baltazar Tabelin ◽  
Hirotaka Takahashi ◽  
Ilhwan Park ◽  
Mayumi Ito ◽  
...  
Keyword(s):  
Mobile Phones ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Ammonium Thiosulfate ◽  
Thiosulfate Leaching

Thermodynamic analysis of the copper (I) homogeneous and heterogeneous speciation in ammonium thiosulfate leaching systems

2019 ◽  
Vol 97 (9) ◽  
pp. 651-658 ◽  
Author(s):  
Igor Povar ◽  
Stefano Ubaldini ◽  
Oxana Spinu ◽  
Tudor Lupascu
Keyword(s):  
Complex Formation ◽  
Thermodynamic Analysis ◽  
Mixed Ligand Complex ◽  
Chemical Species ◽  
Mixed Ligand ◽  
Phase System ◽  
Ligand Complex ◽  
Complex Species ◽  
Ammonium Thiosulfate ◽  
Thiosulfate Leaching

The paper presents a new thermodynamic approach to studying mixed ligand complex formation reactions in the multi-component two-phase system “cuprous oxide-ammoniacal copper (I) thiosulfate aqueous solution” under real conditions. The quintessence of the developed approach consists in the thermodynamic analysis of concurrent reactions in the heterogeneous system Cu(I) – NH3 – S2O32− – H2O on the basis of the introduced notion of generalized reaction equations. A detailed thermodynamic analysis in ammonium thiosulfate leaching systems has considered the formation of mixed ligand complex species Cu(OH)i(NH3)j(S2O3)k. The new feature is to focus on the chemical description of the overall process of complex formation consisting of a series of concurrent reactions, where the nature and ratio of the concentrations of chemical species, formed in such reactions, depend on the ratio of the concentrations of the metal Cu+ and ligands, temperature, and other thermodynamic parameters. On the basis of the selected thermodynamic data for involved species, the thermodynamic stability areas of solid phase and the repartition of soluble and insoluble chemical species towards the solution pH and a number of total reagent concentrations in heterogeneous mixtures have been investigated. The diagrams of heterogeneous and homogeneous chemical equilibria are used for the graphical representation of complex equilibria and distribution of soluble and insoluble species in examined systems. The used approach utilizes thermodynamic relationships coupled with original mass balance constraints, where the solid phases are explicitly expressed. The obtained results are useful for optimization of the overall scheme of thiosulfate leaching in gold hydrometallurgy to minimize reagent consumption and maximize gold extraction.

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