Gold is a highly required material for a wide range of personal and industrial applications. The high demand for gold, together with the shortage of natural resources and high pollution potential of wastes generated during mining and ore processing activities led to search for alternative sources of gold. A possible source is represented by mine …
Other treatment methods involve cyanide leaching, thiourea leaching, ammoniacal thiosulfate leaching, carbon-in-pulp, and resin-in-pulp, all of which are less commonly utilized. Read more Article
The target of this review is to point out the best cyanide-free processes of following methods and reagents: Bioleaching, Chlorination, Aqua Regia, Bromine, Thiocyanate, Thiosulfate and Thiourea ...
Recent research results demonstrate that thiourea decomposition is quite slow in the presence of ferric sulfate for simple solutions. Ferric sulfate and formamidine …
Thiosulfate leaching has been regarded as a promising alternative to cyanidation, but it still faces the challenge of the recovery of low content of gold from high concentrations of thiosulfate solutions. Liquid–liquid extraction is a method to address this issue but is still limited by the use of volatile and toxic organic solvents. To overcome …
conditions and the gold recovery and TU consumption. This prediction method can be used as an auxiliary decision-making tool in the TU gold leaching process, and it has broad engineering application prospects in engineering. Keywords:goldconcentrate;thiourea;artificialneuralnetwork;greyrelationalanalysis;influencingvariables …
The author concluded that the thiourea technique was uneconomical when compared to traditional cyanidation approaches. A recent paper by Chen, et al. (1980), discusses the leaching of gold and silver by "acidothioureation." Figure 4 compares acidic thiourea and cyanide leaching of gold and silver.
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 thiosulfate complexation with gold, forming a …
Trans. Nonferrous Met. Soc. China 34(2024) 322âˆ'335 Thiourea leaching of gold in presence of jarosite and role of oxalate Ke LI, Qian LI, Tao JIANG, Yong-bin YANG, Bin XU, Rui XU, Yan ZHANG School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China Received 24 July 2022; accepted 10 April …
Application of the thiourea-Fe3+ leaching system resulted in recovery of 16.4 ± 1.56 mg/kg of gold from the fine-grained PIR within 6 h of incubation. Due to high gold market prices, upscaling of the suggested technology can represent a suitable strategy for gold recovery from PIR and other MSWI residues.
1.. IntroductionThe use of thiourea, NH 2 CSNH 2, as an extracting agent for precious metals has shown promise for implementation in the metallurgical industry [1].Thioureation has received considerable interest as an alternative lixiviant for gold over the last few years [2].. Laboratory testing has indicated that a thiourea process for gold …
In this research, we studied the use of microwave pretreatment to enhance the efficiency of Au leaching from gold concentrate. The gold concentrate was pretreated using microwaves with different irradiation time. The sample temperature was increased up to 950 °C by the microwave irradiation. A scanning electron microscope-energy dispersive …
The gold industry has been seeking alternative reagents for leaching gold from low-grade ores for the past 25 years. The cost and transport of cyanide, the poor recovery of gold from carbonaceous ores, the lack of selectivity of cyanide towards copper minerals and the cost of waste treatment are real factors which can make cyanide …
Discussion This work has adopted a factorial design approach to the assessment of thiourea leaching of the copper-gold ore. Eighteen experiments were used to create a model which describes the leaching of gold on the basis of selected factors. The study showed that acid washing is essential prior to thiourea leaching (Fig. 6).
Au(solution) is the amount of gold in the thiourea solution, Au(solid) is the amount of gold in the feed sample before the leaching process, and Vt is the total volume of solution (l), and [Au] is ...
Gold is dissolved in an acidic thiourea solution according to the following anodic reaction: Au + 2CS(NH2)2 = Au(CS(NH2)2)2+ + e-(1) Ferric sulfate is a preferred oxidant because of its mild oxidation potential and fast kinetics for gold dissolution. However, it is important to note that the …
The most tested leaching agents for gold are thiosulfate, thiourea, thiocyanate and halides [19, 20, 21]. An effective Au recovery process from mining …
So far, several studies employed thiourea leaching for precious metal extraction from e-wastes as well as from natural Au-bearing ores/concentrates, as summarized in Table 1.Biohydrometallurgical technologies (bioleaching and biooxidation) have been successfully used in mining industries, primarily to leach valuable base …
Fig. 2 shows the variation of gold dissolution and thiourea consumption as a function of time in the absence and presence of chalcopyrite. As can be seen from Fig. 2 (a), the presence of chalcopyrite significantly hindered the dissolution of gold in thiourea solution; the gold dissolution kept decreasing as the chalcopyrite content increased from …
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 …
Gold mining is a global business carried out in every continent ex-cept Antarctica. Approximately 190000 tons of gold has been mined since 1950; however, high-quality ores have gradu- ... composition behavior of thiourea during gold leaching with thiourea mixed with pyrite as an impurity was studied to evaluate the effect of pyrite on the ...
This review aims to provide an up-to-date evaluation of thiourea-gold leaching studies from electronic waste, with emphasis on the recent progression from …
The optimum parameters for gold leaching process were determined to be 100 mM H 2 O 2, 50 mM Fe 2+, 20 g/L thiourea, and pH = 1.5. Under these conditions, gold leaching achieved an ultra-high efficiency, rapidly leaching gold from a roasted gold concentrate within 30 min.
The experimental results from thiourea leaching of a gold ore showed that under the optimal conditions of [TU] 0.08 M, [Fe 3+] 0.04 M, pH 2.0, and temperature 40 °C, additives could significantly reduce the thiourea consumption and improve the gold extraction, which are comparable to that obtained by cyanidation. With the same …
In thiosulfate leaching of gold, the copper-ammonia complex serves as an oxidant and catalyst. This study examined the impact of magnetizing the copper-ammonia thiosulphate lixiviant solution on gold leaching from refractory oxidized ores. Magnetization reduced surface tension, improved wettability and infiltration, and enhanced the diffusion …
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+ …
Solution potential plays a key role in the gold leaching process, which is closely associated with gold dissolution and TU stability. The variation of solution potential in the presence of arsenopyrite was measured and recorded as shown in Fig. 2, but only the situation without addition of oxalate was discussed in this section.As shown in Fig. 2 (a), …
To achieve effective leaching of gold, thiourea was added to facilitate gold extraction. This research not only investigated the leaching conditions and leaching …
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 …
Non-cyanide gold leaching serves as a promising green approach for eliminating cyanide utilization and the resulting environmental pollution from cyanide …
