cyanide leaching minerals

PDF | On Jun 10, 2010, Alex Mezei published Factors influencing the rate of gold cyanide leaching and adsorption on activated carbon, and their impact on the design of CIL and CIP circuits | Find ...

Cyanidation tailings often contain a certain amount of gold, which is difficult to recover due to the influence of associated minerals. In this article, lead oxide was used to increase leaching efficiency and decrease sodium cyanide consumption. The mechanism of lead oxide-enhanced gold leaching was studied by thermodynamic …

Cyanide Leaching. A cyanide solution, or lixiviant, is percolated into ore deposited in vats, columns or heaps during the cyanide leaching process. ... for which mineral acids such as HCl, H 2 SO 4 or HNO 3 are used in conjunction with H 2 O 2, a powerful oxidant that enhances the acid's leaching efficiency. For the recovery of copper from ...

Copper minerals present difficulties during the cyanide leaching of gold ores leading to excessively high consumption of cyanide (and oxygen) coupled with low extraction of gold. Copper cyanide species, if present at high levels, adversely affects the downstream processes such as the activated carbon adsorption and the effluent treatment.

This paper proposes a robust methodology to estimate leaching cyanide consumption due to oxidation and reactions with gold, chalcopyrite and pyrite minerals forming various …

The chemical recovery of gold can be defined by two different operations: the oxidative dissolution of gold and the reductive precipitation of metallic gold from the solution. Cyanide is one of the most attractive lixiviants in the current industrial gold …

With cyanide concentration of 0.75 g/L only 80% gold extraction was achieved, which was attributed to gold telluride minerals in the ore, which lead to categorize the studied gold ore as a mildly refractory. This is actually lower than the gold extraction with cyanide-free glycine leaching (90%).

It was shown that gold recovery during cyanide leaching increased from 6.47 to 62.21% relative to an increase in cyanide concentrations from 250 to 4500 g/t. At a cyanide concentration of 2000 g/t and a glycine concentration of 0.5 mol/L in the absence of H 2 O 2, gold recovery was 78% and increased to 88% and 93% with an increase in …

Early studies on the dissolution of gold in cyanide solution in the presence of sulfide minerals have shown that heavy metal components, such as Cu, Fe and Zn, significantly increase the consumption of both cyanide and oxygen (Habashi, 1967). In addition, the sulfide component has been shown to have a strong impact on the gold …

Gold Leaching with Copper Minerals present. Copper is probably the most active and one of the most troublesome of the cyanicides. The results of a series of tests to determine the solubility of copper minerals in cyanide solution. They show that asurite, chalcocite, cuprite, malachite, and finely divided metallic copper are readily and ...

Special Issue Information. Dear Colleagues, Economically-significant quantities of gold, silver, copper, and uranium are currently extracted using heap leaching technology, and the technology is being explored also for nickel, zinc, PGMs, rare earths, as well as electronic circuit boards and nitrate minerals. Design of heap leach operations, …

The occurrence features of ultrafine iron minerals in a cyanide leaching residue produced from a superlarge gold mining company in Yunnan Province were determined with chemical composition analysis, iron phase analysis, and mineral liberation analysis (MLA). The results show that the residue contains 26.74% iron, mainly occurring …

Since the sulfide minerals are to some extent soluble in cyanide solutions, there will always be some sulfur species present in the leach solution. It has been shown that soluble sulfide hinders the rate of gold leaching, forming a protective layer of the type Au/S x. Electrochemical studies of the constituent half reactions: gold oxidation ...

The ongoing depletion of gold and silver-containing ore deposits demands a shift towards the processing of more complex sources. Leaching of gold or silver from these sources, which are named refractory and are typically low-grade, can be complicated due to one or more of the following effects: (1) kinetic or thermodynamic impediments on …

YU et al [10] reported that ultrasound- assisted cyanide leaching could increase the extraction rate of gold and shorten the leaching time significantly. ... [44,45]. Hence, the presence of mineral particles in the ultrasound-assisted cyanide leaching process strengthens the cavitation process. In a separate test, cullet was used to replace …

Typical cyanide concentrations used in cyanide leaching range from 300 to 500 mg/l (0.03 to 0.05% as NaCN) depending on the mineralogy of the ore. However, in practice, the amount of cyanide used in leach solutions is dictated by the presence of other cyanide consumers, and the need to increase the rate of leaching to acceptable levels.

Cyanide leaching is the major hydrometallurgical method for the recovery of gold from ores on a commercial scale. There are many different factors that can affect cyanide leaching, such as the associated minerals in the ore, that can impact the levels of cyanide and oxygen available for the cyanidation process.

This may result in dissolved oxygen starvation for the oxidative leaching of the gold, and ultimately it will reduce the maximum attainable recovery of gold from the ore. In addition, the presence of sulphides leads to extra consumption of the cyanide-leaching agent, NaCN, due to the formation of thiocyanate, therefore increasing costs.

1. Introduction. Leaching is a central unit operation in the hydrometallurgical processing of minerals (Crundwell et al., 2011).Often a leaching stage is one of the initial operations in the process, and as a result the efficiency of leaching has a primary effect on the technical and economic success of a hydrometallurgical business.

The direct cyanide leaching rate of gold from a gold calcine was only 71.33%, due to 19.51% of gold being encapsulated in the iron oxides. ... The gold inclusions in gangue minerals can be exposed hardly during roasting; on the other hand, the high content of the gangue minerals, i.e., silicates, possibly cause the blockage of particle …

Evidence shows that cyanide compounds linger in affected plant and fish tissues and can persist in the environment for long periods of time. How is Cyanide used in mining? …

It is common to distinguish free milling from refractory on the basis of the intensity of cyanide leaching required: it is greater than 90% in the case of the former, and less than 80% for the latter ... which is used in leaching. The Iberian Minerals Ltd. announced in 2016 a patent for the HM X-leach, a non-cyanide based leach formula, ...

Aylmore, M. G. Alternative lixiviants to cyanide for leaching gold ores. Developments in Mineral Processing, 501–539 (2005). Akcil, A. et al. Precious metal …

After gravity separation, middlings and tailings are transferred to cyanide leaching (Laplante and Gray 2005). ... Gold (Au) is frequently recovered from mineral ores using sodium cyanide in aqueous solution as a distinct cyanide complex. This combination is known for its considerable solubility in water and notable stability when in contact ...

In the formula, M 1, M 2 are the weight of raw material and dry weight of alkali leaching residue (g); ε means the leaching rate (%); β 1 means the grade of Te in the alkali-leaching residue, and β 2 refers to the grade of Te in gold leaching tailings. Cyanidation Leaching Gold Tailing Oxidation Roasting-Alkali Leaching Test. After …

These include leaching with caustic soda, roasting, fine grinding, and weathering, followed by cyanidation. ... Leaching of Arsenic And Antimony Sulphide Minerals with Cyanide. A series of tests were run to investigate the effects of strongly alkaline and weakly alkaline cyanide solutions on the decomposition of arsenopyrite, …

cyanide leaching of gold", Hydrometallurgy, Vol. 78, ... and selenides (Xu et al. 2014) on the microscopic scale within other minerals including marcasite (Fleet and Mumin 1997) and sphalerite ...

In order to study the galvanic interactions between sulfide minerals and gold in more detail, two electrodes, one gold electrode and one mineral electrode, were simultaneously leached in 5 mmol L − 1 cyanide solution. The REQCM was used to measure the gold leaching rate and the corresponding mixed potential when it was …

ultrafine iron and gold minerals from a cyanide leaching residue, which contained 29.55% iron and 5.60 g/t gold, and a leaching ratio of 91.26% for iron and 71.43% for gold was,

The mineral itself is remarkably gold rich, with the gold being found in a molecular association with the element tellurium. On a weight basis, ∼44% of the weight of the mineral is gold. 1.2. Toxicity. ... The cyanide leaching of tellurides has a history of controversy, with some researchers maintaining that successful gold extraction could ...

It was found that cyanide leaching was the better performing technology compared to thiosulphate leaching, as it achieved gold extractions of 71.6%, 69.7%, and 67.8% for the three ore samples (Sample 1, Sample 2, and Sample 3, respectively),

The cyanidation process is affected by a number of influential parameters, such as the availability of oxygen at the solid–liquid interface, the pH and Eh of the solid–solvent suspension, the presence of ions other than CN − in solution, the cyanide concentration, the particle size of the mineral, the temperature, the surface area of gold …

Dissolution of copper minerals may adversely affect cyanide leaching leading to high consumption of cyanide and poor extraction of gold (Dawson et al, 1997, Alymore and Muir, 2001; Breuer et al ...

When the cyanide-to-copper molar ratio drops to 2.5 and a large proportion of copper is present as Cu(CN)2, the gold leaching rate is extremely low [18]. This suggests that Cu(CN)3 2 can provide sufficient cyanide ions for the leaching of gold or other minerals according to Equation (9) [18]. 4Au + 8Cu(CN)3 2 + O 2 + 2H2O !4Au(CN)2 + 8Cu(CN) 2 ...