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Lead nitrate has been used as additive in gold processing plants for more than 60 years to improve gold recovery and leaching kinetics. It was reported by Guo et al. that pretreatments of gold ore by lead nitrate reduce the extent of gold surface coating by silver, iron and sulfur (Guo et al., 2004; Deschenes et al., 1998).
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 …
Adding lead nitrate had a negligible effect on gold extraction whilst improving silver extraction. Dissolution of copper was substantially suppressed by adding lead nitrate, i.e., from 23% (no Pb ...
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 …
Gold ore with low soluble copper (and thus amendable to direct cyanidation) 2. ... Drok and Ritchie (1997) prepared the gold samples by plating from a solution dosed with silver nitrate, which resulted in a gold–silver alloy (∼0.7% Ag), to more closely mimic naturally occurring gold, ...
The flux is a mixture of several reagent chemical such as borax, silica, sodium nitrate, sodium carbonate and fluorspar. Borax is a white crystalline mineral used in glass and ceramic enamel mixes. ... the …
The base cyanidations of MC confirmed the refractory behavior of the ore associated with gold and gold-silver tellurides. In a conventional cyanidation process …
Keywords: gold, cyanide leaching, pyrite, copper, refractory ore, lead nitrate 1. Introduction Cyanidation is the dominant process for the treatment of gold and silver ores. Under atmospheric conditions, aerated, relatively dilute solutions of cyanide are readily used to dissolve gold present in the ore as an aurocyanide complex.
Gold recovery improved from 92% to 98% with two solution changes. The presence of carbon-in-leach process (CIL) was shown to achieve a similar gold recovery. Lead nitrate was shown to be beneficial in reducing residue grades in all cases. Fine grinding of the concentrate to 22 mm with CIL leaching improved recovery further to 98.6%.
A process and system for recovery of gold from an ore having the steps of i) providing the ore containing the gold to be recovered, ii) leaching the ore in an oxidative chloride medium, including a nitrogen species to produce a solution comprising gold; and iii) recovering the gold from the solution. The gold in a preferred embodiment is recovered …
Previous work on a sulphide-beating gold ore indicated a 50% decrease in cyanide consumption using lead nitrate while keeping the same gold recovery, but increasing leaching kinetics by 30% (DeschSnes and Wallingford, 1995). The difference in the response of the ore to the addition of lead nitrate is attributed to the duration of the …
Stripping carbon for example with high silver loadings is uneconomical as the below figures show based on $1,000/tonne stripping cost for carbon: Silver price US$16.61/ounce. Gold price US$1093 ...
(1) Optimizing the additive reagents, e.g., cyanide, oxygen, and lead nitrate are metallurgical approaches to improve the process kinetics and overall gold leaching. 6 …
1.. IntroductionAmong reagents that improve cyanidation, oxygen and lead nitrate are known to enhance gold recovery and lower cyanide consumption, especially in the presence of sulphide minerals 1, 2, 3.A survey of Canadian cyanidation plants indicated that the level of lead nitrate addition varies from one location to another [4].There is no …
The results indicate that the strategy of lead nitrate addition, to be optimal, should be a function of the mineralogical composition of the ore. The formation of a passive layer on gold particles has a significant influence in the initial stages of leaching. The addition of lead nitrate notably decreased its inhibiting effect.
A Flowsheet to recovery gold from sulfide ores. There are many arrangements and combinations using flotation in conjunction with treatment of gold ores. The two gold process flowsheets shown, with some variations, are probably the most commonly used. In Gold Flowsheet No. 1 the ore is ground in water to such a size as to …
Roasting and Processing Sulpho-telluride ore to recover gold. This roasting plant, since closed down, was equipped with eight standard 70-spindle Edwards roasters, though only four were finally in use. ... borax, 33 per cent sand, and 25 per cent sodium nitrate. This flux serves to remove bismuth which is present in the gold. GOLD LOSSES …
Effect of lead nitrate addition on the leaching of a pyrrhotite-bearing gold ore (Cyanidation: pH 11.2, 380ppm NaCN, 8ppm O 2, 32h) Figure 5 illustrates the reaction of cyanide with chalcopyrite ...
Those types of gold ores which most frequently require roasting include ores carrying arsenopyrite, stibnite, sulphotellurides, and pyrrhotite. Straight pyritic ores, where the pyrite is present in small …
Drok and Ritchie (1997) prepared the gold samples by plating from a solution dosed with silver nitrate, which resulted in a gold–silver alloy (∼0.7% Ag), ... As expected, the copper in the circuit reduced to a low level, but when sulfide copper–gold ore processing resumed, the copper concentration in the leach circuit did not attain ...
Only ~12% of gold was extracted by direct cyanide leaching of the ore. The addition of lead nitrate did not affect the leaching of gold. When ammoniacal cyanide leaching system was used, the ...
The application of lead nitrate in combination with oxygen generated the best results. Gold extraction of 96% can be obtained with cyanide consumption of 0.51 kg/t and lime consumption of 0.60 kg/t in 24 hours. ... Roasted gold ore, magnetic tailings, and synthetic maghemite electrodes exhibited a cathodic peak, suggesting the reduction of ...
Lead Nitrate addition in CIL operations and how the dosage of Pb Lead nitrate affects gold leaching kinetic rates. The main aim for adding lead nitrate is to help in Gold dissolution in CIL plants. ... It gives a great benefits with regards to the gold dissolution probably because of the ore we treat contains traces of appreciable sulphides ...
For a gold ore with a low sulphide content, lead nitrate addition can be performed directly to the cyanidation. A gold ore with a higher sulphide content, with a low sulphide content but finely ground, or with a significant amount of copper sulphide minerals requires a pre-leaching with a lead nitrate addition.
This ancient Gold Refining method is one in that the nitre must be " projected " upon the gold just before it melts, as it has little effect on molten gold. The method is still in wide use. The bullion is melted in clay crucibles, and a little nitre (potassium nitrate) or sodium nitrate is thrown on to the surface of the metal.
Since the late 19 th century, cyanide has been the industry standard used for recovery of gold and silver from multitude of ore types. The ... lead nitrate and 3-nitrobenzene sulphonate to name a few. For safety reasons, pH typically needs to be controlled in the 9.5-12.0 range depending on applications. While it feasible to achieve this using ...
The addition of activated carbon increased the gold recovery up to 67%, Test 9. Furthermore, in the presence of additional lead nitrate (224 g/t feed), the highest gold extraction of 88% was achieved (Test 10). In Test 11 with thousands times greater addition of lead nitrate, gold extraction was also of a similar magnitude, 83%.
The addition of lead nitrate significantly alters the gold dissolution rate behaviour. ... Gold ore sample A was crushed and ground to 80% passing -325 mesh (~45 /~m). This fine size distribution is used at the mill to 15) increase gold liberation. A second gold ore, sample B, was crushed and ground to 80% passing -270 mesh (~53 #m). ...
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 gold ...
