Gold leaching is the key stage in process of gold mining. There are a few well-reputed leaching methods using a variety of different reagents. Nowadays the most …

The chemical reaction of gold leaching by JC is similar to that of cyanide, while the CN − of JC will not dissociate easily (Conclusions. In this study, a novel environmentally friendly gold lixiviant, "Jinchan", was applied to leach the Carlin-type gold concentration. The main conclusions are drawn as follows: (1)

During the roasting of gold concentrate to improve gold recovery, arsenic is released into the air and valuable elements such as Fe, Cu, Zn, and Pb are converted into oxide minerals. In this research, we evaluated the release of As and the loss of valuable metals during the acid baking and hot water leaching processes used for gold …

ammonium hydroxide after 24 h. Addition of copper(II) as <0.2 mM only slightly enhanced the gold leaching in the ammoniacal thiosulfate solution. Gold leaching drastically decreased as the concentration of copper(II) increased 0.2 mM due to the degradation of S 2 O 3 2-. Keywords: gold, extraction, leaching, thiosulfate, Saudi ore Introduction

Leaching, often gold, is the process of extracting a soluble constituent from a solid by means of a solvent. In extractive metallurgy, of gold, it is the process of dissolving a certain mineral (or minerals) from an ore or a concentrate, or dissolving certain constituents from materials such as a calcines, mattes, scrap alloys, anodic slimes, etc., …

Most mining companies in Ghana experience siltation problems during leaching of gold ore. This paper examines the potential causes and possible mitigation measures of siltation. Particle size ...

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 (10–500 mM), …

During leaching of the as-received gold concentrate, the pulp pH was found to decrease markedly from 11 to 7–8, severely hindering the leaching of gold. Thus, the pretreatment of NaOH leaching was performed for the concentrate to make pH relatively stable during the leaching process. Prior to each leaching test, the gold concentrate …

Thiosulfate gold leaching is an alternative gold leaching method, especially for leaching of preg-robbing gold ores. ... (AF 5) catalyst during the leaching of copper concentrates in the acidic ...

The oxidation roasting of carbon-bearing micro-fine gold can eliminate or weaken the robbing effect of carbonaceous materials and clay, and destroy the encapsulation of micro-fine gold. The micropores produced by gas escaping during the roasting process are conducive to the diffusion of leaching agents, thus enhancing the …

As the second application of biotechnology, we should mention the leaching of gold using biologically produced lixiviants that can produce ligands that solubilize …

The kinetic analysis showed that the leaching process of tellurium from telluride-type gold concentrate was a mixed type of chemical reaction control and diffusion control. The grain parameter in the leaching process was 0.26263 and the apparent activation energy E = 17.12 kJ/mol. Tellurium could be pre-leached from the telluride-type …

Treatment of gold-bearing ore with hydrogen peroxide during heap leaching of gold increases gold recovery by 1.2% and amounts to 55.89%, without treatment - …

The cyanidation of copper flotation tailings containing sulfides for gold recovery is an example of the formation of cyanide complexes with copper and silver during the leaching process [11,12]. Figure 4 shows the MLA Automated Minerology image of an ore sample from a copper mine in Mexico, containing chalcopyrite and bornite as copper …

Gold leaching yields from gold ore concentrate and e-waste by R. tolerans and R. mucosus were as shown in Figure 1 and p-values from two- and one-way ANOVA were as shown in Table 3 and ... The impact of bacterial species on triiodide concentration during gold leaching from ore concentrate was significant for days 1 and 5, but not on …

Riina Ahtiainen, Mari Lundström Add to Mendeley https://doi/10.1016/j.jclepro.2019.06.197 Get rights and content Under a Creative …

In the carbon-in-pulp process activated carbon is mixed with a ground ore plus water slurry in which gold and silver cyanides are dissolved. After the precious metals are adsorbed onto the carbon, the loaded carbon is separated from the pulp and stripped. The barren pulp is disposed of as tailings and the …

The paper dedicated to the safe gold leaching with thiosulfates and organic salts of polythionic acids (organic base polythionates). The method of production of these polythionates based on the Smolyaninov reaction is described in stages and in details for the first time. Possible application of the polythionates application in the gold ...

Gold bioleaching mediated by iodide oxidizing bacteria (IOB) has been proposed as a sustainable alternative to conventional technologies such as cyanidation. This study evaluated the ability of two …

All cultures were filtered to remove biomass after 168 h of growth on the respective sulfur substrate and immediately prepared for leaching. The temperature of 50 • C and copper concentration of ...

Cyanide-free mild chloride leaching was investigated. •. Gold could be recovered even at <520 mV vs. Ag/AgCl in carbon-in-chloride-leach mode. •. Copper was a stronger oxidant than iron in gold leaching. •. Gold was oxidized by in-situ dissolving impurities. •. Seawater contains enough chlorides to dissolve gold.

Refractory gold ore is usually affected by the associated carbonaceous matter through the preg-robbing effect, which is eliminated by oxidation roasting, followed by leaching, to achieve a satisfactory gold leaching efficiency. Roasting–leaching experiments, pore structure measurements, scanning electron microscopy (SEM), and X …

Groudev et al. (1999) used solutions that contained amino acids of microbial origin and thiosulphate to leach the gold and silver from oxide ores that contained 3.5 g/t of gold and 14 g/t of silver. First, an alkaline solution (pH 10–10.5) was irrigated on the top of the heap to stabilize the pH.

During the gold leaching process, the influences of the external diffusion steps ((a) and (e)) on the kinetics can be ignored with proper stirring in the UCM. Therefore, the internal diffusion and chemical reaction steps are the major processes that affect the kinetics and rate-controlling step of gold leaching.

A gold ore sample originated from an epithermal deposit with a composition shown in Table 2 was used as a feed material in the leaching experiments. X-ray fluorescence and inductively coupled plasma optical emission spectrometry (ICP-OES; Thermo Scientific iCAP 6000, USA) were used to determine the chemical composition of …

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 …

The consumption of cyanide during processing operations is a major economic cost in the extraction of gold from its ores, while the discharge of cyanide wastes may result in significant environmental pollution. Many factors influence the levels of consumption and discharge of cyanide, including ore mineralogy and lixiviant solution …

Pak et al. (2020) report that an increase in AuC l 4 − concentration impedes gold leaching, as gold ions in the solution readily precipitate into Au(OH) 3. The result is a low leaching rate. The concentration of AuC l 4 −, therefore, should not be too high during the leaching process.

Iodide-oxidizing bacteria (IOB) oxidize iodide into iodine and triiodide which can be utilized for gold dissolution. IOB can be therefore useful for gold leaching. This study examined the impact of incubation conditions such as concentration of the nutrient and iodide, initial bacterial cell number, incubation temperature, and shaking condition on the …

The particle size of gold is tiny, and it is wrapped by sulfide and can't be effectively contacted with the gold-leaching agent (Nan et al., 2014; Qin et al., 2021; Silva et al., 2020). The phenomenon of "gold adsorption loss with the carbonaceous matter" exists in carbonaceous gold ore during the cyanidation process.