The Newmont Mining company has developed a process of bio-oxidation and thiosulfate heap leaching for low-grade carbonaceous sulfide gold ores (Schmitz et al., 2001). Xu et al. (2016) developed an environmentally friendly process of alkaline pressure oxidation-thiosulfate leaching to extract gold from a high C (3.61%), As and Sb bearing …

A combined chemical and biological heap leaching of an oxide gold-bearing ore containing 3.5 g/ton of gold and 14.0 g/ton silver has been reported. One thousand tons of crushed ores (−15 mm) were heap leached in stages. Initial treatment involved alkaline solutions of pH 10–10.5 containing protein hydrolysates and thiosulfate (mixture of ...

The apparent activation energies of gold leaching in the thiosulfate-only and Cu-NH 3-S 2 O 3 2− systems are 30.9 kJ/mol and 8.01 kJ/mol, respectively. It can be concluded that the cobalt-ammonia catalysis for thiosulfate leaching of gold has higher catalytic efficiency than copper-ammonia catalysis.

thiosulfate leaching process is also applicable for the heap leaching process.28,31) However, there are problems in commercializing the thiosulfate process in the gold milling industry, the problems are the most notably high reagent consumption and varying gold extraction results for the different ores under the same leaching conditions. Further-

The processes can employ heap leaching or lixiviants that include one or more blinding agents. Processes are provided for recovering precious metals from refractory materials using thiosulfate lixiviants. The processes can employ heap leaching or lixiviants that include one or more blinding agents.

thiosulfate leaching process is also applicable for the heap. leaching proce ss. 28,31) However, there are problems in. commercializing the thiosulfate process in the gold milling.

I recently read that sodium thiosulfate can be used for gold and silver leaching in much the same way as cyanide, but with no worries about toxicity. This intrigues me: aqua regia is a pain to work with, and cyanide is too toxic for an amateur, but thiosulfate is already one of my favorite reagents - cheap, nontoxic, and has so many uses.

The processes can employ heap leaching or lixiviants that include one or more blinding agents. ... Where gold is the precious metal, thiosulfate leaching techniques have typically relied on the use of copper ions to catalyze and accelerate the oxidation of gold, ammonia to facilitate the formation and stabilization of cupric ammine ions and/or ...

Thiosulfate is one of alternative reagents to cyanide; many plants still uses cyanide as the primary reagent for gold leaching even though its side effects to environment are well …

The microbial communities are important for minerals decomposition in biological heap leaching system. However, the differentiation and relationship of composition and function of microbial communities between leaching heap (LH) and leaching solution (LS) are still unclear. In this study, 16S rRNA gene sequencing was …

Some preliminary results on the secondary leaching of previously heap leached gold ore are presented. Alternative lixiviants for gold comprising chlorine, thiourea and thiosulphate were compared ...

US7722840B2 US10/713,640 US71364003A US7722840B2 US 7722840 B2 US7722840 B2 US 7722840B2 US 71364003 A US71364003 A US 71364003A US 7722840 B2 US7722840 B2 US 7722840B2 Authority

The processes can employ heap leaching or lixiviants that include one or more blinding agents. US8097227B2 - Method for thiosulfate leaching of precious metal-containing materials - Google Patents ... Method for thiosulfate leaching of precious metal-containing materials Download PDF Info Publication number US8097227B2.

The characteristics of using thiosulfate as a gold recovery chemicals are: (1) non-toxic, (2) fast leaching speed, generally only takes 3 hours to achieve the best economic effect, (3) can process refractory …

Biooxidation of gold can be applied as heap or dump leaching and stirred tank leaching. The static biooxidation techniques are based on the principle of …

The processes can employ heap leaching or lixiviants that include one or more blinding agents. WO2004046036A3 - Method for thiosulfate leaching of precious metal-containing materials - Google Patents ... Method for thiosulfate leaching of precious metal-containing materials Download PDF Info Publication number WO2004046036A3.

Heap leaching involves stacking of metal-bearing ore into a heap on an impermeable pad, irrigating the ore for an extended period of time with a chemical solution to dissolve the sought-after metals, and collecting the leachant as it percolates from the base of the heap. ... Other leaching agents, such as thiosulfate, thiourea, hypochlorite ...

The leaching of silver sulfide by a copper-ammonia thiosulfate solution occurs either by the substitution of cupric or cuprous for silver. The cupric reaction is favored due to a thermodynamic ...

The reaction order was −0.61 for Ag, considering a thiosulfate concentration between 200–500 mol·m−3, while, for Au, it was −0.09 for a concentration range between 32–320 mol·m–3.

The average gold extracted between the surface tailings and 1m deep tailings within just 5 h reaction time is 73.9 % for thiosulfate leaching and 73.4 % for cyanide leaching. Considering that ...

The process of recovering precious metals from ores containing precious metals, such as gold and silver, from an aqueous ammoniacal thiosulfate leach solution to provide a significant practical and economical process for the recovery of gold or silver. After leaching of the ore with an aqueous ammoniacal thiosulfate solution, the leach solution is …

Sodium Thiosulphate Gold Leaching. 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 …

Table 1 illustrates the side reactions occurring in thiosulfate leaching systems. These reactions not only result in the loss of lixiviant, but the formation of solid precipitates can also potentially passivate gold surfaces, limiting the gold leaching efficiency (Jeffrey et al., 2008).In addition to thiosulfate oxidation adding to reagent cost, the …

A schematic diagram of the heap leach process used by Newmont Gold Co during the thiosulfate leaching stage is shown in Figure 7 (Aylmore and Muir, 2001). After passing through the heap, the pregnant lixiviant solution was recovered at the bottom of the heap and recirculated, either continuously or intermittently.

Thiosulfate is an alternative lixiviant for the leaching of precious metals. Research and development of thiosulfate leach technology has been prompted by …

In the recent years, several silver leaching technologies have been investigated in order to find out an alternative and sustainable leaching process; one of these alternatives is the thiosulfate.The main research line is focused in the use of thiosulfate with copper as a catalyst and ammonia as a cupric ion stabilizer; however, …

This method is very useful to optimize the heap leaching process (design, analysis, control and optimization) and also proposes optimal flow rates for the heap leaching process [14] of gold [15 ...

Assesment of Ammoniacal Ammonium Sulpha te Leaching as a Pretreatment Process for Copper Bearing Gold Ores. Haci Deveci, A. Deniz Bas. Download Free PDF. View PDF. Book. 124 pp. FixPrint; Pushchino; …

The catalytic effect of Pb 2+ adsorption on gold surface in gold thiosulfate leaching was investigated by electrochemical methods. Open circuit potential (OCP), cyclic voltammetry (CV) and polarization tests showed that 50 and 100 mg/L Pb 2+ addition to thiosulfate solution increased the OCP from −0.136 V to −0.110 and −0.105 V, …

A development of in situ gold leaching using ferric EDTA and ferric oxalate complexes in thiosulfate solutions has been studies by Heath et al. (2008). However, in thiosulfate-iron (III) system the operating pH must be controlled, which increases the complexity of the application of this system in heap or in situ leaching.