Pyrrhotite Cyanide Consumption

Cyanide Leaching and Decomposition of Pyrrhotite

The results of the foregoing tests show that intense aeration of pyrrhotite in a strongly alkaline solution reduced the cyanide consumption by 4 to 5 lbs of NaCN/ton of pyrrhotite The greater part of this saving was due to less formation of thiocyanate under conditions of intense aeration

Gold Metallurgy & Leaching in Cyanicides

The reason for the lower cyanide consumption obtained with intense aeration is probably connected with the reactions which take place when alkaline sulphide decomposes in cyanide solution Alkaline sulphide is one of the initial products of the reaction between pyrrhotite and alkaline cyanide solution

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Nov 06, 2018 · Predicting Cyanide Consumption in Gold Leaching: A Kinetic - MDPI Mar 8, 2018 The consumption of cyanide during processing operations is a major economic cost in the extraction of gold from its ores, while the discharge of

Cyanidation of gold ores containing copper, silver, lead

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 (Dai and Jeffrey, 2006) 12 Factors affecting gold leaching

Advances in the Cyanidation of Gold - ScienceDirect

However, the presence of reactive pyrrhotite resulted in a cyanide consumption of 315 kg/t NaCN Three key features were identified to optimize the process: the use of a pretreatment, the addition of oxygen and the addition of lead nitrate

The influence of pyrite pre-oxidation on gold recovery by

The reduction of the cyanide concentration in the leaching solution from 1 to 05% and the addition of 100 g Pb(NO 3)2/t allowed the reduction of the cyanide consumption to 276 kg NaCN/t (58%

(PDF) Cyanidation of a pyrrhotite-bearing gold ore

The cyanide consumption is about the same for both conditions Fi gu re 7 Ef fe ct of ox yg en on go ld l ea ch in g o f a pyrrhotite-bearing gold ore (Cyanidation: pH 112, 200g/t

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Cyanidation of a pyrrhotite-bearing gold ore Cyanidation of a pyrrhotite-bearing gold ore , gold leaching: a group that has a , The calculation of cyanide consumption was based on gold mining process control using cyanide - YouTube

The Effect of Increasing Capacity on Gold Recovery and

Fulton, 2003) Excessive cyanide causes the formation of cyanide complexes with impurities in system If the sample contains sulfide compounds, then more cyanide may be needed (Marsden, J, I House, 2006) In any case, consumption of non optimal cyanide could have a negative effect on gold recovery process (Deschênes,

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Jun 28, 2018 · Mar 8, 2018 to estimate leaching cyanide consumption due to oxidation and reactions with gold, chalcopyrite and pyrite minerals forming various cyanide In this paper, the role of grinding media type on cyanide-based gold leaching in the presence of pyrrhotite was investigated Pyrrhotite commonly occurs in many

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Jun 28, 2018 · Mar 8, 2018 to estimate leaching cyanide consumption due to oxidation and reactions with gold, chalcopyrite and pyrite minerals forming various cyanide In this paper, the role of grinding media type on cyanide-based gold leaching in the presence of pyrrhotite was investigated Pyrrhotite commonly occurs in many

The Metallurgy of Cyanide Gold Leaching – An Introduction

Sulphide Minerals: Some sulphide minerals (eg pyrrhotite) will oxidise during the leach and generate acid This reaction will consume the oxygen in solution, and without this oxygen the reaction of Au and Cyanide cannot proceed, regardless of the liberation of the gold

INFLUENCE OF PRE-AERATION ON CYANIDE LEACHING OF A …

sulphides, and decreases cyanide consumption Morrison (1994) explained the role of lead nitrate as a catalyst at the surface of the gold preventing passivation It also inhibits the dissolution of metallic sulphides providing a decline in cyanide consumption

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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 chemistry

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Cyanide Leach Packet - EARTHWORKS Gold Leaching Oxygen can be used , gas and promotes the leaching of gold from ores by enhancing , throughput and lower cyanide consumption in your leaching process Cyanidation of a pyrrhotite-bearing gold ore Cyanidation of a pyrrhotite-bearing gold ore , gold leaching: a group that has a , CYANIDE

INFLUENCE OF LEAD NITRATE ON CYANIDE LEACHING OF …

the dissolution of metallic sulfides, thus reduces cyanide consumption (Deschenes et al, 2003) Metallic sulfides such as pyrite, chalcopyrite and pyrrhotite show different reaction mechanisms with lead nitrate Lead nitrate passivizes the pyrite by forming a hydroxide (Pb(OH) 2

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It is pretty unusual to have a sulphide gold float that is not refractory, but I will warn you that with pyrite, pyrrhotite and the copper minerals present your cyanide consumption is going to be high

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increase in cyanide consumption The introduction of lead nitrate resulted in a 34 g/t decrease in cyanide consumption According to La Brooy, Linge, and Walker (1994), reactions involving sulphides may consume cyanide and oxygen and produce various solution species that can decrease the efficiency of gold leaching Pyrrhotite is the most

Effect of the composition of some sulphide - DeepDyve

With regard to the synthetic ores, it was found that pyrrhotite did not generate a high cyanide consumption while pyrite and chalcopyrite were detrimental Pre-leaching was deleterious for the ore containing chalcopyrite while pre-leaching with lead nitrate was very efficient to decrease the reactivity of the ore containing pyrite

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Jul 06, 2018 · Copper/gold ores can be effectively leached by a combined glycine/cyanide solution Cyanide consumption is minerals such as calcite and dolomite are all essentially inert extra equipment required for solid/liquid separation or washing Get Price

The reasons of gold refractory, Gold ore classification

They have a high solubility in the alkaline cyanide, have a large amount consumption of cyanide and dissolved oxygen in the solution, forming a variety of cyanide complex compound and SCN

Effect of the composition of some sulphide minerals on

While the cyanide consumption for the sulphide-free mixture was almost nil at 003 kgrt, the consumption of cyanide was relatively low for the pyrrhotite mixture at Fig 2 Effect of the nature of the pre-leaching of sulphide minerals on cyanide consumption Pre-leaching: pH 115, 8 ppm O 2 , 2 h, 100 grt PbŽNO 3 2 when applied

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EXAMPLE 7 Reduced Consumption of Non-cyanide Lixiviants Two 50-mg samples of pyrrhotite were placed in 50-ml portions of 01% aqueous KMnO 4 solution (00115 mole %) which had been adjusted to pH 120 with NaOH

Maximising the Value of Gold Diagnostic Leaching | Cyanide

Figure 9 shows the theoretical cyanide consumption by those elements or species in solution that could form cyanide complexes (Ni, Ag, Co, Au, Fe and Cu), as well as thiocyanate (SCN) and the actual cyanide consumed (NaCN), assuming 4, 2, 6, 2, 6 and 35 cyanide ions per

Maximising the Value of Gold Diagnostic Leaching | Cyanide

Figure 9 shows the theoretical cyanide consumption by those elements or species in solution that could form cyanide complexes (Ni, Ag, Co, Au, Fe and Cu), as well as thiocyanate (SCN) and the actual cyanide consumed (NaCN), assuming 4, 2, 6, 2, 6 and 35 cyanide ions per

Cyanide Management by SART - sgsca

beginning of the project the cyanide soluble copper (CNSolCu) grades were very low and the impact on the cyanide consumption was minimal From late 1998 the CNSolCu levels began to steadily increase and pockets of high grade CNSolCu ores were discovered These ores had a significant impact on the cyanide consumption

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Jun 24, 2014 · Treatment without pre leaching and without the injection of oxygen results in a gold recovery of 896% and a cyanide consumption of 146 kg/t (test 1) Pre leaching for 30 min with air (test 2) changes almost nothing in the system, even if oxygen is added during cyanidation

Improved leach recovery - IsaMill™ Advantages | Isamill

The preaeration stage removes small quantities of active pyrite and pyrrhotite prior to cyanidation Pre-aeration increases the Eh and oxidises the active pyrite and pyrrhotite to reduce cyanide consumption in the leach process

The Use of Oxygen in Gold Cyanidation | Wesley Griffith

However the observation that cyanide consumption increases with increasing cyanide concentration in the slurry is also evident in plant operations as presented in Fig 4 [15] Increased “free” cyanide concentration in slurries allows the formation of metal cyanide complexes with higher cyanide content

CYANIDE REMEDIATION: CURRENT AND PAST …

CYANIDE REMEDIATION: CURRENT AND PAST TECHNOLOGIES CA Young§ and TS Jordan, Department of Metallurgical Engineering, Montana Tech, Butte, MT 59701 ABSTRACT Cyanide (CN-) is a toxic species that is found predominantly in industrial effluents generated by metallurgical operations Cyanide's strong affinity for metals makes it

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Cyanide Leaching and Decomposition of Pyrrhotite Use of lead salts Lead salts, such as litharge, lead nitrate, etc, when added to cyanide solutions of low lime alkalinity, accelerate the dissolution of gold and reduce reagent consumption, particularly cyanide lost as thiocyanate

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recoveries Cyanide consumption ranged from 16 to 22 kg/t whereas lime ranged from 25 to 32 kg/t Cyanidation of the tails recovered 50% Au and 40% Ag, with Sodium cyanide and lime consumption 07 kg/t and 15 kg/t respectively In all cases, the gold and silver leaching kinetics

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Jul 03, 2018 · Using an excess of cyanide results in unnecessary cyanide consumption and has Did lead nitrate is added in cyanide leaching to prevent the adverse effect of Figure 9 Effect of lead nitrate addition on the leaching of gold ore with pyrite, pyrrhotite and chalcopyrite (Deschénes

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Predicting Cyanide Consumption in Gold Leaching: A Kinetic - MDPI Mar 8, 2018 Cyanide losses in the leaching stage mainly occur via the action of [7] showed that use of lead nitrate and oxygen (200 and 16 mg·L-1, respectively) of cyanide consumption in gold processing plants and showed it to be

Process Parameters for Bio-oxidation of Sulphur in the Pre

problems by increasing cyanide consumption and decreasing the environmental quality of the residue In this research bacterial oxidation of sulphur was simulated in volumetric and Erlenmeyer flasks where inoculums were added to sulphur suspension to catalyse the oxidation of sulphur Some of the

The Facts About Cyanides

What are the properties of cyanide? There are several chemical forms of cyanide Hydrogen cyanide is a pale blue or colorless liquid at room temperature and is a colorless gas at higher temperatures It has a bitter almond odor Sodium cyanide and potassium cyanide are white powders which may have a bitter almond-like odor

Gold recovery from a refractory pyrrhotite ore by biooxidation

Further- more, these species tend to precipitate the gold already oxidised ŽVeglio` et al, 1995a, while the decomposition of pyrrhotite forms compounds such as thiocyanide or ferro- cyanide that can consume free cyanide during the recovery of gold ŽUbaldini et al, 1995

Aachen Reactors - Application 1 Cyanide leaching of gold

pre-aeration to overcome the chemical oxygen and cyanide demand of mineral components such as pyrrhotite or other sulphides aeration to provide oxygen for the cyanidation leach reactions Efficient aeration is required for both steps to optimise energy and reagents