The effect of pyrite, pyrrhotite, chalcopyrite, realgar and arsenopyrite on gold dissolution in cyanide media was investigated. The cyanidation of synthetic gold ores in the presence of various concentrations of sulfides was studied under constant experimental conditions. A mineralogical analysis of the minerals was performed. The leaching …Web

It was reported that pre-leaching successfully overcame the effect of pyrite and pyrrhotite on cyanide consumption and the gold leaching kinetics, but it had no beneficial effect when chalcopyrite was present. It was suggested that lead nitrate prevented copper and iron dissolution by forming a passive layer at the surface of sulfide …Web

Deschênes et al. 12,13,14 added lead nitrate to cyanide leaching of gold ore containing 4.2% pyrrhotite; gold extraction can reach 94.2%, and adding lead …Web

The addition of lead nitrate, directly to the leach, showed 94.2% gold extraction with only 0.16kg/t NaCN consumption. ... Reduction of gold on the pyrite was observed to occur with the release of ...Web

Increased phosphorus availability may provoke serious eutrophication problems in wetlands. Strong evidence indicates that sulphate induced mobilization of phosphate (internal eutrophication) has been responsible for a strong decline of the biodiversity in wetlands during the last decades. It is currently underestimated, however, …Web

The effect of lead nitrate was studied in gold cyanidation leaching in both direct leaching and pretreatment + leaching conditions. Gold recovery increased by …Web

In addition, lead ions can accelerate gold dissolution during cyanidation via the formation of AuPb 2, AuPb 3 and metallic lead, hence improving the gold leaching rate (Deschenes et al. 2000). In Newmont's Lone Tree Plant in Nevada, it was found that cyanide in process water decreases gold flotation recovery, but the application of lead ions ...Web

Several leveraging strategies were explored to improve gold leaching during cyanidation in the presence of pyrite, chalcopyrite, sphalerite and chalcocite. Galena, used a source of lead, was found to largely neutralize the negative effect of sulfide minerals dissolution on gold leaching, especially in the cases of pyrite, chalcopyrite and …Web

Further, addition of lead nitrate to CICl was shown to improve gold recovery substantially (88%). The investigation shows that the presented cyanide-free leaching approach can address the refractory nature of gold concentrates in atmospheric pressure - the simultaneous oxidation of sulfide minerals and gold in a single unit process providing ...Web

The nitric acid pre-treatment improved the extraction of gold and silver in subsequent cyanide leaching (1.5 g/L NaCN) to 82% Au and 87.5% Ag with a concomitant decrease (up to 54%) in cyanide ...Web

50% monoclinic and 50% hexagonal. A leach using 8ppm dissolved oxygen yielded only 82.3% gold extraction with a 0.29kg/t NaCN consumed. The addition of lead nitrate, directly to the leach, showed 94.2% gold extraction with only 0.16kg/t NaCN consumption. A gold extraction of 95.0% was obtained by adding oxygen with lead nitrate.Web

Earlier studies have focused on the impact of these parameters on gold leaching. Besides gold, this study demonstrated the behaviour of silver and base metals (copper and zinc) from the pyritic gold concentrate. Adding lead nitrate had a negligible effect on gold extraction whilst improving silver extraction.Web

open access Highlights • Atmospheric single stage leaching • Gold extraction showed linear dependency on sulfide oxidation • carbonaceous material • • …Web

Lead nitrate has proved to be effective in enhancing gold leaching kinetics, enhancing gold overall extraction and reducing cyanide consumption. Many cyanidation plants add …Web

Lead nitrate forms a hydroxide layer on pyrite particles, which reduces the reaction rate with cyanide. The disolution of pyrite generates a sulphur layer on gold. …Web

to 10.5 by adding hydrated lime at the mill feed conveyor. Lead nitrate is added in the cyclone underflows slurry which is returned to the ball mill. Sodium cyanide is added to the slurry in the first leach tank, and the concentration is adjusted to about 750 mg/L. The leached gold is adsorbed in the counter-current carbon-in-leach circuit.Web

DOI: 10.1016/S0892-6875(00)00109-6 Corpus ID: 97067548; Effect of lead nitrate on cyanidation of gold ores : Progress on the study of the mechanisms @article{Deschnes2000EffectOL, title={Effect of lead nitrate on cyanidation of gold ores : Progress on the study of the mechanisms}, author={Guy Desch{^e}nes and Rolando …Web

The introduction of lead nitrate resulted in a 2.28% increase in extraction. Studies have shown that the addition of lead nitrate can be beneficial to gold leaching kinetics. Lead passivates the surface of reactive sulphides and forms insoluble lead sulphide, thus effectively preventing the solution from contacting the sulphides.Web

Gold can be efficiently extracted from the Central zone sample of Clarence Stream Property, NB. using a cyanide concentration as low as 250 ppm NaCN with the addition of lead nitrate and kerosene. Leaching gold from an ore containing aurostibite at atmospheric pressure, with a low cyanide concentration, without any pre-treatment, is a …Web

Cyanidation is the main process in gold leaching. There are several parameters that affect gold recovery and cyanide consumption. In this paper, the effect of the oxidative pretreatment and lead nitrate addition on the cyanidation of Zarshuran refractory gold ore containing 3.32 ppm Au, 1.09% As, and 0.5% sulfur were …Web

The ore is refractory and contains free gold and gold tellurides as well as gold associated with pyrite. After SAG milling and ball-milling, the ore is processed by flotation followed by roasting of the pyrite concentrate at the nearby Gidji roaster. ... The plant did not use lead nitrate and practiced leaching at pH 11. Download : Download ...Web

Haci Deveci. A. Deniz Bas. Copper minerals present difficulties during the cyanide leaching of gold ores leading to excessively high consumption of cyanide (and oxygen) coupled with low extraction ...Web

For example, Deschênes et al. showed that use of lead nitrate and oxygen (200 and 16 mg·L −1, respectively) with high pyrite or chalcopyrite ores lowered cyanide consumption threefold and enhanced …Web

An effort to enhance the gold leaching rate by adding lead nitrate addition was not successful. Experiments with a fine gold powder mixed with the ore indicated a relationship between the gold surface and the lead added. ... For pyrite, a pre-leaching without lead nitrate was beneficial with a decrease of 83% in cyanide consumption (from …Web

Oxygen demand of each gold ore is dependent on the pyrite content and its mineralogical origin. The oxidation of sulphide ion into sulphate and iron into ferric ion during pretreatment is beneficial to subsequent cyanide consumption. Gold leaching optimization studies were performed with one gold ore sample.Web

Effect of Lead Salt Addition to Cyanide Solution. Figure 2 shows the effect of lead nitrate on a gold dissolution in a cyanide solution. In the absence of lead, the first peak detected between –0.3 and –0.1 V was very weak with the current density less than 0.1 mA/cm 2 at different cyanide concentrations (Fig. 2 a).Web

Lead nitrate Oxygen Sulphides 1. Introduction In the past 25 years, most of the development in the cyanidation of gold has occurred in response to the decreasing …Web

The absence of lead nitrate is associated with a 12.1% reduction in gold extraction for the retention time of the leach circuit. Laboratory work indicated an increase in gold-leaching kinetics with a higher dissolved-oxygen content, but such a system is not as effective as a leach with lead nitrate. Download : Download full-size image; Fig. 14.Web

Deschênes et al. 12,13,14 added lead nitrate to cyanide leaching of gold ore containing 4.2% pyrrhotite; gold extraction can reach 94.2%, and adding lead nitrate to assist leaching of gold ore containing 0.4% chalcopyrite, gold extraction increased from < 90% to 98%. When combined with lead nitrate and oxygen, the leaching kinetics of …Web

Non-cyanide gold leaching serves as a promising green approach for eliminating cyanide utilization and the resulting environmental pollution from cyanide use. ... and it shows that 14.5% of gold is occluded by a passivating layer of iron oxides, arsenopyrite, and pyrite except for 3.58% of gold in quartz minerals. Table 1. Chemical …Web

A gold extraction of 93.9% was obtained in 24 hours with the addition of 50g/t lead nitrate compared to 78.1% without lead nitrate. ... View in full-text CitationsWeb

Oxygen demand of each gold ore is dependent on the pyrite content and its mineralogical origin. The oxidation of sulphide ion into sulphate and iron into ferric ion during pretreatment is beneficial to subsequent cyanide consumption. Gold leaching optimization studies were performed with one gold ore sample. Cyanide consumption was found to be ...Web

In addition, based on the effects of djurliete, bornite, and chalcopyrite on gold leaching in the Ammonia-Cyanide process, the addition of lead nitrate can effectively improve the gold leaching rate and reduce the consumption of cyanide in this process [17]. While these studies mainly focused on the effect of lead salts on the leaching of gold ...Web

According to the trend, the gold extraction obtained with 2–3 kg/t lead nitrate appears not to be biased and would probably have to be in the range of 2.2 g/t Au. At dosages above 4 kg/t lead nitrate, the gold content of the leach residue was observed to slightly increase; considering the ±0.1 g/t variation in fireWeb

Effect of lead nitrate. Some works have shown that lead nitrate addition increases gold leaching kinetics and decreases cyanide consumption by reducing the sulfide dissolution (Deschênes et al ...Web

Litharge accelerates gold dissolution. — The use of litharge was found essential to produce a good tailing in the period of agitation available. Under conditions applicable to plant practice (i.e. using classifier overflow and mill solution), as low as 0.20 lb. of litharge/ton of ore was found to accelerate the dissolution of gold greatly.Web

Automated mineralogy results demonstrated that most of the gold in the concentrate is present as an invisible gold form, and 63.7 wt% of gold was distributed in pyrite. Diagnostic leaching results ...Web

Pyrite, arsenopyrite: Cyanidation: Lead nitrate addition and cyanide-level control improved gold recovery; cyanide consumption drop: 26: Musselwhite: Ontario: ... Small-scale industrial application of thiourea leaching, with gold recovery on activated carbon: 27: Goldstrike: United States:Web

Gold Smelting & Refining Process. Gold can be concentrated and recovered by applying different gold refining process methods and the final product has variable quality. In this way, it is necessary to have a better marketable product so that the incomes can be improved. Then, we have two smelt and cast the gold into bars called …Web