Highlights Thiourea is a selective and less hazardous agent as an alternative to the conventional and toxic cyanide. The agent was applied to leach gold and silver from PCBs of waste mobile phones. The influence of the particle size, thiourea and Fe 3+ concentrations and temperature was investigated. In the best condition, about 90% of …
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The influence of particle size, thiourea and Fe (3+) concentrations and temperature on the leaching of gold and silver from waste mobile phones was investigated. Gold extraction was found to be ...
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Thiourea leaching of gold (Au) from e-wastes can be considered an alternative to highly toxic cyanidation, provided that its reagents consumption can be largely reduced. ... Thiourea leaching gold and silver from the printed circuit boards of waste mobile phones. Waste Manage., 32 (2012), pp. 1209-1212, 10.1016/j.wasman.2012.01.026.
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was assessed using leaching conditions of 24 g/L thiourea, 0.6% iron (III), pH of 1.00 at 25 °C for a period of two hours. They reported that samples of < 149 µm resulted in around. 90% gold ...
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Thiourea Leaching of Gold and Silver — Technology Update and Additional Applications. J. Hiskey. Published 1 August 1984. Materials Science, Chemistry. Mining, Metallurgy & …
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The first (reported) attempt made to use thiourea to dissolve gold and silver was in 1941. It must take place in acidic conditions, following the anodic reaction shown in Reaction 23 (Örgül and Atalay, 2002). ... Leaching of gold, silver and accompanying metals from circuit boards (PCBs) waste. Acta. Montan. Slovaca, 16 (2011) Google Scholar.
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Early workers such as Plaksin and Kozhukhova (1941) used thiourea to dissolve gold and silver in H2SO4 and H2O2. They …
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Abstract. Thiourea was used to leach gold from ore containing 0.4% Cu and 5.6 g/t Au. The parameters studied were acid pretreatment, leaching time, pH, thiourea concentration and the oxidizing agents used. Gold extraction was 89% and thiourea consumption was 3.9 kg/t. No acid consumption was observed during leaching at pH 3.
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2022. The nature of gold (Au) ore deposits plays an essential role in determining the best gold recovery method as an alternative to cyanidation, considering …
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This study involved preliminary laboratory test work to identify the relative leaching response to cyanidation and thiourea leaching of an oxidized low grade gold ore based on characterization studies.
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The use of ammoniumâˆ'thiosulfate solutions to leach gold and silver from the oxidizing leaching residue of copper sulfide concentrates was reported by BEREZOWSKY and SEFTON in 1979 [25]. ... (13): 1301âˆ'1306. [13] ÖRGÃœL S, ATALAY Ãœ. Reaction chemistry of gold leaching in thiourea solution for a Turkish gold ore [J ...
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Besides pure gold samples, also a gold-silver specimen was used in one trial to determine the influence of the alloying element silver in thiourea leaching systems.
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In this study, we investigated two thiourea leach-ing processes for effective recovery of Ag and Au from flue dust. The effects of various parameters on the process, such as leaching time (1–10 h), thiourea concentration (20–60 g/L), pulp density (20–100 g/ L), and leaching temperature (20–60 C), were sys-JOM, Vol. 70, No. 8, 2018
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The use of thiourea as an alternative lixiviant to gold cyanidation for processing gold-bearing ores or concentrates was first developed by Soviet metallurgists in the 1940s. However, the interest for thiourea leaching of gold mainly came during the 1980s and 1990s to establish a parallel process. The chemistry of thiourea is simpler than ...
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Abstract. The leaching of gold in thiourea–thiocyanate solutions has been studied by the rotating-disc technique using ferric sulfate as oxidant. The effects of initial concentrations of ferric ...
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The effect of a preliminary acid leaching for the recovery of gold by thiourea from printed circuit boards (PCBs) of spent mobile phones, was investigated and qualitative considerations on the technical and economic feasibility of the different routes were made.
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Recovery of Gold and Silver from Secondary Sources of Electronic Waste Processing by Thiourea Leaching. Award ID(s): 1747765 NSF-PAR ID: 10081333 Author(s) / Creator(s): Lee, Hyunju; Molstad, Emily; Mishra, Brajendra Date Published: Journal Name: JOM Volume: 70 Issue: 8
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The experimental results obtained in the flotation and leaching with free cyanide of 2000 mg/L at pH 11.6 and Eh −18 mV and with 0.2 M thiourea at pH 1.5 and Eh + 528 mV of an ore containing gold, silver, and copper show that the flotation is carried out efficiently, however during the leaching in both systems the percentage of dissolution ...
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Since the initial report of thiourea as a complexing reagent for gold leaching, considerable research has been directed toward the use of thiourea as an alternative to cyanide for gold extraction from different auriferous mineral resources. At the same time, some fundamental investigations of the system have been reported. In this …
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nism of gold and silver leaching by thio urea in sulphuric medium and in presen ce of Fe 3+ ... An innovative thiourea gold leaching process. Hydrometallurgy 1998, 48, 113–124, doi:10.1016/S0304 ...
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The plant, part of the FENIX project, consists of two hydrometallurgical technologies of which, GOLD REC 1, includes an oxidative base metal leaching method combined with thiourea leaching for gold and silver . Despite this limited industrial use, thiourea as a leaching reagent has … See more
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Thiourea Leaching: An Update on a Sustainable Approach for Gold Recovery from E-waste. March 2022. Journal of Sustainable Metallurgy. DOI: …
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The influence of particle size, thiourea and Fe(3+) concentrations and temperature on the leaching of gold and silver from waste mobile phones was investigated. Gold extraction was found to be enhanced in a PCBs particle size of 100 mesh with the solutions containing 24 g/L thiourea and Fe(3+) concentration of 0.6% under the room temperature.
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Thiourea Gold Leaching. The use of thiourea, (CS (NH2)2 as a complexing/extracting agent for gold and other precious metals has shown promise for implementation in the mining/metals industry. Laboratory testing of this reagent has indicated that a thiourea process for gold extraction has several advantages over …
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Thiourea Leaching of Gold. February 2018. DOI: 10.1201/9781315150475-5. In book: Gold Metallurgy and the Environment (pp.127-140) Authors: Sadia Ilyas. Hanyang University.
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Abstract. The present communication deals with the leaching of gold and silver from the printed circuit boards (PCBs) of waste mobile phones using an effective …
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Thiourea leaching gold and silver from the printed circuit boards of waste mobile phones. Waste Manage., 32 (6) (2012), pp. 1209-1212. View in Scopus Google Scholar. Li and Miller, 2002. J. Li, J.D. Miller. Reaction kinetics for gold dissolution in acid thiourea solution using formamidine disulfide as oxidant.
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Thiourea (Tu) leaching of gold is an alternative lixiviant for treating sulfide gold ores and concentrates. ... It has been studied to leach gold and silver by TU from ores (La Brooy et al., 1994 ...
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In this work, stepwise thiourea leaching was used to extract gold and silver from refractory gold concentrate calcine. In the first stage, gold and silver extractions of 84.42% and 44.15% are obtained by thiourea leaching without any additive, respectively, which are further enhanced to 88.71% and 52.65% by adding the additives of lignin ...
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Thiourea leaching of gold from a quartz vein type ore without the addition of additive was investigated to show the effect of leaching conditions including Fe 3+ concentration (0.02–0.05 M), thiourea concentration (0.05–0.13 M), pH (1.0–2.5), leaching time (4–7 h) and temperature (25–50 °C) on gold extraction and thiourea consumption. . …
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The nature of gold (Au) ore deposits plays an essential role in determining the best gold recovery method as an alternative to cyanidation, considering environmental concerns. Thiourea (Tu) leaching of gold is an alternative lixiviant for treating sulfide gold ores and concentrates. The present study investigated the leaching behavior of Au from …
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Waste circuit boards contain a rich resource of recoverable metals such as Cu,Au,Ag,Pt,and Pb.Its disposal,harmless and recycling have become the key problems solved urgently with the economic development.Thiourea leaching gold and silver from the waste circuit board was carried out,and the influence of leaching time,react temperature,thiourea …
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Thiourea, as an environmentally friendly gold lixiviant, has the potential to replace highly toxic cyanide. The effect of foreign ions including Cu 2+, Ag +, Pb 2+, Zn 2+, AsO 3 3− and AsO 4 3− on gold leaching in an acidic thiourea solution was investigated in this paper. Leaching results showed that the foreign ions had an adverse effect on …
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The nature of gold (Au) ore deposits plays an essential role in determining the best gold recovery method as an alternative to cyanidation, considering environmental concerns. Thiourea (Tu) leaching of gold is an alternative lixiviant for treating sulfide gold ores and concentrates. The present study investigated the leaching behavior of Au from sulfide …
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The thiourea leaching of gold and silver from electronic waste, goldsmith's waste and ceramic waste using crushing as the pretreatment step was investigated. For electronic waste, it was possible to achieve 97 % gold and 94 % silver recovery within 120 minutes of thiourea leaching. Up to 98 % of gold and 96 % of …
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In this paper, oxalate and citrate were used as additives to enhance. the thiourea leaching of gold from a gold ore. The leaching results showed that the thiourea consumption was. signi cantly ...
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M ICROBIALLY ENHANCED THIOUREA LEACHING OF GOLD AND SILVER 57 TABLE 3 Gold and silver extractions obtained in thiourea leaching of the bacterial leach residues at pH 2.3 Duration of Duration of % gold and silver extracted the bacterial thiourea leach (days) leach (h) without oxone with oxone Au Ag Au Ag 0 4 …
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Gold recovery from actual leach thiourea solutions has been investigated by electrowinning. The main electrochemical reaction occurring at the cathode surface is the …
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The residue from the first stage was subjected to thiourea leaching in the presence of 0.052 M ferric sulfate to extract the undissolved silver. Extractions of 12.41 % silver and 1.55 % gold were realized after 15 minutes of leaching time. The final extractions of gold and silver was 45 % Ag and 2 % Au after one hour of leaching.
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By using cross-linked persimmon tannin gel resin, recovery of gold and silver thiourea leaching solutions became favourable (Ashiq, Kulkarni et al. 2019). Bio-Metallurgy Process Bio-metallurgy is a metal recovery process in which microbes are used for bioleaching the metal from e-waste concentrate (Ilyas and Lee 2014, Hennebel, Boon …
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