Gold Leaching from an Oxide Ore Using Thiocyanate as a …
Thiocyanate gold leaching is an electrochem. reaction which occurs at pH 1.5-2.5 and electrochem. potential of 600-700 mV. The literature shows fast gold leaching kinetics in well-designed thiocyanate systems. The solubilized gold-thiocyanate species can be recovered from the pregnant leach soln. by a variety of methods including conventional ...
Thiocyanate hydrometallurgy for the recovery of gold.
Acid thiocyanate leaching of gold was investigated in the presence of ferric sulfate as an oxidant. According to leaching kinetic studies the initial rate of gold leaching is slow, and not significantly dependent on thiocyanate (0.05–0.2 M) and ferric (0.1–1.0 g/L) concentrations. Ferrous and cupric ions had no effect on leaching kinetics under …
Leaching of gold in thiocyanate solutions. Part …
Thiocyanate gold leaching is an electrochemical reaction which occurs at pH 1.5–2.5 and electrochemical potential of 600–700 mV. The literature shows fast gold leaching kinetics in well ...
Thiocyanate hydrometallurgy for the recovery of gold.
Highlights Thermodynamic analysis of (Au, Ag, Cu, Fe)-SCN-H 2 O systems was performed. The findings are useful in understanding the leaching and recovery of gold. Gold can be leached in thiocyanate solutions with ferric sulfate as the oxidant. Gold forms aurous or auric complexes with thiocyanate. Ferric ion forms a series of cationic …
A systematic review of gold extraction: Fundamentals, …
Similar to acid thiourea leaching, Fe(III) is an excellent oxidant in gold thiocyanate leaching with low cost and high effect. Generally, thiocyanate gold leaching is carried out under the following conditions: pH of 1.5–2.5, temperature of 15–50 °C, and molar ratio of dissolved Fe 3+ /SCN-of 2–20 (Azizitorghabeh et al., 2021). 3.1.4.
Thiourea–thiocyanate leaching system for gold
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, thiourea (Tu) and thiocyanate as well as temperature and pH on gold leaching rates were studied. An initial gold leaching rate in the order of 10 − 9 mol ...
A review of gold extraction using alternatives to cyanide: …
Thiocyanate: Gold leaching occurs under acidic conditions (pH < 3), commonly using Fe(III), H 2 O 2 or MnO 2 as the oxidant. The leaching kinetics is relatively fast, and the gold leaching ratio is relatively high. The thermodynamic stability of SCN – is relatively low, and is readily oxidized to sulfate, carbonate, and ammonium.
Gold Leaching from an Oxide Ore Using Thiocyanate as a …
The viability of thiocyanate leaching was confirmed in 1989, 9 and subsequent studies have reported gold recovery ranging from 93% (oxide concentrate in 0.6 M NH 4 SCN in the presence of glycine and 0.05 M Fe 3+, pH 2) to 95% (hard arsenopyrite in 0.4 M KSCN, pH 2–5). 11,14 Many studies have investigated …
Thiocyanate facilitating thiosulfate extraction of gold via …
To further research the effect of adding thiocyanate, the gold leaching percentage and sodium thiosulfate consumption were compared with adding thiocyanate and without thiocyanate, and the results were shown in Table 2. Gold leaching percentage was 62.99% without thiocyanate, and sodium thiosulfate consumption was 137.24 kg/t.
Thiocyanate solutions in gold technology
Abstract. The scope for using KSCN solutions in the field of gold leaching from chemical preparation products of hard arsenopyrite concentrates is shown. More than 95% gold is recovered in weak acidic solutions (pH=2–5) at KSCN concentration 0.4 mol/L. The thiocyanate complexes are recovered on carbon adsorbents (BAU, UC, LKAU-4) …
(PDF) Iodide—thiocyanate leaching system for gold
Thiocyanate gold leaching is an electrochemical reaction which occurs at pH 1.5–2.5 and electrochemical potential of 600–700 mV. The literature shows fast gold leaching kinetics in well ...
A review of thiocyanate gold leaching
Thiocyanate is 1000 times less toxic than cyanide and is a very strong gold leaching lixiviant. This review paper provides an overview of the chemistry, …
Application of the Thiocyanate-Thiourea System for the Leaching …
The study conducted by Yang et al. demonstrates that the use of these two reagents for gold leaching produces a synergistic effect . In addition, Lin et al. [ 13 ] have shown that the addition of thiourea in the thiosulfate leaching process provides an ecologically viable, efficient, and fast leaching method for the hydrometallurgical …
Thiourea–thiocyanate leaching system for gold
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, thiourea (Tu) and thiocyanate as well as temperature and pH on gold leaching rates were studied. An initial gold leaching rate in the order of 10 − 9 …
Overview of the Challenges and Opportunities in Processing Complex Gold
Despite these remarkable results of fast leaching rate and gold recovery, the thiocyanate dosage of 0.6 mol/L (equivalent to 45.67 g/L) is still high which may affect process economics. Further, the high liquid-to-solid ratio may require the use of larger or many leaching tanks in the operation which will add to equipment capital cost.
Selective gold recovery from pregnant thiocyanate leach …
Gold can be extracted by thiocyanate in the presence of ferric sulfate as an oxidant under acidic conditions with a pH range of 1 to 3 and ORP of 600–700 mV (Eqs. (1), (2)). Gold leaching by thiocyanate from oxide and sulfide ores has been studied in previous research (Azizitorghabeh et al., 2021a; Azizitorghabeh et al., 2021b). …
Iodide—thiocyanate leaching system for gold | SpringerLink
The leaching of gold by thiocyanate solutions is performed at pHs between 1 and 2, which allows the use of iron(III) as an oxidizing agent. The mechanism of dissolution of gold by iron(III)-thiocyanate solutions is directly linked with the autoreduction process, in which Fe III is spontaneously reduced to Fe II while oxidizing SCN-This oxidation proceeds …
Gold Leaching from an Oxide Ore Using Thiocyanate as a …
Thiocyanate (SCN-) is a promising alternative to cyanide as a lixiviant for gold extraction and is 1000 times less toxic than cyanide.In this study, the following leaching parameters were tested to optimize the gold recovery for the first time from an oxide ore using the response surface methodology: initial thiocyanate concentration (10 …
Leaching of Gold from an Oxide Gold Ore with …
The leaching behavior of gold from an oxide gold ore using copper–tartrate–thiosulfate solutions has been investigated. Experimental parameters, including temperature, initial pH, and concentrations of copper tartrate and thiosulfate, were systematically studied. The capability of gold leaching using copper–tartrate–thiosulfate …
Thiocyanate hydrometallurgy for the recovery of gold.: Part …
Abstract. Acid thiocyanate leaching of gold was investigated in the presence of ferric sulfate as an oxidant. According to leaching kinetic studies the initial rate of …
The role of glycine in the ammonium thiocyanate leaching of gold
As gold concentrate is oxidized, SCN − would also be oxidized to SO 4 2−, NH 4 + and CO 3 2– by oxidant, which leads to a large dosage of the agent when thiocyanate is used for leaching gold. As glycine is added into the thiocyanate leaching solution, glycine will combine with ferric ions to form a more stable complex than iron …
Thiocyanate Part 1: A Problem in Gold Mining
Thiocyanate is a growing environmental challenge for the gold industry. Harmful to both humans and aquatic life, thiocyanate presence is becoming more prevalent in gold mining effluents. It is formed when cyanide reacts with sulphur containing minerals and/or compounds released into solution during the metallurgical extraction of gold. Ore …
Iodide—thiocyanate leaching system for gold | SpringerLink
The leaching of gold by thiocyanate solutions is performed at pHs between 1 and 2, which allows the use of iron (III) as an oxidizing agent.
Hydrometallurgical Recovery of Gold from Mining Wastes
Generally, gold leaching using thiocyanate (0.01–0.05 M) occurs at a potential of 0.4–0.45 V, pH 1–3, in the presence of an oxidant like ferric ions (2–5 g/L) or peroxide. It has been shown that, under optimal conditions, a gold extraction yield of 95% can be achieved . Thiocyanate concentrations in the range of 0.5 to 5 g/L and Fe (III ...
Hydrometallurgical Recovery of Gold from Mining Wastes
Generally, gold leaching using thiocyanate (0.01–0.05 M) occurs at a potential of 0.4–0.45 V, pH 1–3, in the presence of an oxidant like ferric ions (2–5 g/L) or …
(PDF) A systematic review of gold extraction: Fundamentals
thiourea leaching, Fe(III) is an excellent oxidant in gold thiocyan ate leaching with low cost and high effect. Generally, thiocyanate gold leachin g is carried out under the following conditions:
Synergistical thiourea and thiosulfate leaching gold from a gold …
Glycine diminishes the consumption of thiosulfate, but not facilitates gold leaching, and has a long leaching time (48 h) [20]. Urea is selected as the additive, and gold leaching efficiency is improved from 88.42 % to 88.71 %, whilst sodium lignosulfonate needs to be added to the leaching process [21]. This may make components of the …
The role of glycine in the ammonium thiocyanate leaching of gold
Open circuit potentials show that thiocyanate stability is increased in the mixture.Research Highlights Initial gold leaching rate of the order of 10− 9 mol cm− 2 s− 1 was obtained in the ...
THIOCYANATE LEACHING OF GOLD
THIOCYANATE LEACHING OF GOLD by Roselyn Sarpomah Yeboah B.Sc., University of Mines and Technology-Tarkwa Ghana, 2015 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES
Electrochemical dissolution behavior of gold and its main
The thiocyanate system can complete gold leaching under acidic and alkaline conditions, and the effect of acid thiocyanate leaching is better [6,7,8,9,10,11,12,13,14]. The thiocyanate system consists of thiocyanate and oxidant and can leach gold directly from ore, concentrate calcine and waste printed circuit boards.
