function of naoh during leaching of gold ores

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 · Low gold and silver leaching kinetics has been commonly observed in traditional gold-silver cyanidation process, especially in heap leaching and in situ leaching operations. The different mineralogy of gold and silver in the ores is suspected to be the main reason, e.g., the occurrence of low solubility acanthite (Ag 2 S) typically results in ...

of the gold present in an ore. Generally, silver is also dissolved by the cyanide solution and follows the gold through the process sequence. Iron sul- fide minerals, which are common constituents of gold ores, are oxidized to some extent during the cyanide leach, thus resulting in the formation of acid.

The hydrometallurgical leaching of native gold from gold-bearing ores or the dissolution of gold metal during the recycling of electronic and precious metal scrap is performed every day using ...

2,4 h, and 2M NaOH solution in a 2-L autoclave. Cyanidation of the leach residues resulted in 90 to 93 pct Au and 60 to 80 pct Ag extractions, compared with only 5 and 15 pct, respectively, without the pretreatment. The procedure was further tested by leaching a low-grade gold ore and a bulk sulfide flotation concentrate prepared from it.

2,4 h, and 2M NaOH solution in a 2-L autoclave. Cyanidation of the leach residues resulted in 90 to 93 pct Au and 60 to 80 pct Ag extractions, compared with only 5 and 15 pct, respectively, without the pretreatment. The procedure was further tested by leaching a low-grade gold ore and a bulk sulfide flotation concentrate prepared from it.

 · With a telluride-type gold ore flotation concentrate as the research object, the Na 2 S + NaOH collaborative leaching process was applied to selectively separate tellurium before

The aqueous pressure oxidation of gold bearing arsenopyrite concentrates in alkaline solution was investigated as a function of O2, pressure and NaOH concentration. Dissolution of gold from the leach residue was accomplished by standard cyanidation. Gold extraction was found to be proportional to the degree of arsenopyrite oxidation. Alkaline pressure oxidation at 160°C, 2413 kPa O2, and 2 M ...

 · This work aims to shed light on the leaching kinetics of antimony from stibnite ore in potassium hydroxide (KOH) solution. Response surface methodology based on central composite design was used to investigate the effect of time, temperature, solid to liquid ratio (S/L), and KOH concentration as independent parameters on the leaching efficiency of antimony. According to the results, time …

The ideal leaching time NaOH for complete extraction of arsenic is 1.88 mol of was defined as that needed to extract enough arsenic such NaOH per 100 g ore according to equation 1. Table 4 that a high extraction of gold would result from the indicates that more than stoichiometric NaOH was re- cyanidation of the oxidative leach residue.

addition of NaOH and H2SO4 solutions. Leaching solutions were sampled at periodic intervals for subsequent analysis. Leaching of the ore sample-A was conducted in a covered 2 L PYREX glass beaker under the room temperature. 500 g ore sample-A was leached in 1 L solution up to 48 h. Comparative leaching of ore

Most cyanide leaching is carried out at a alkaline pH of between 10 and 11, depending upon lab testing of individual ores and the optimum leaching/chemical use rates. The cyanide solution strength is also important in leaching gold, with the typical range of solution being in the 0.02% -0.05% NaCN. The gold particle size has a tremendous effect ...

The gold is mixed with the sodium cyanide which leads to the following Elsener''s equation and reaction. This is done to make soluble gold; Now the gold is soluble. This method of making soluble gold is known as leaching. In the process of leaching, a dilute form of sodium cyanide is added into the ore containing the gold.

 · It is known that gold can be efficiently leached from gold- bearing ores using a mixture of hydrochloric acid, ferric chloride, and manganese dioxide.12 The chemical reaction involved during …

 · This was the first commercial method used for gold extraction. Place the ore into the mortar and grind it to the size of sand grains. Put the ore grains into a plastic bowl. Add the 35-percent hydrochloric acid to the sodium hypochlorite bleach into a flask or beaker, in a two-to-one ratio of acid to bleach. Ensure that the liquid mixture is at ...

Keywords: Carbonaceous Gold Ore, Activated Carbon, Carbon -In Leach, Cell Free Extracts 1 Introduction Gold ores can be categorised based on metallurgical processes as refractory and non-refractory. Refractory gold ores are ore types that are insusceptible to direct leaching by cyanide or simple gravity concentration. They can either be

Leaching Process Examples. An example of the leaching process would be the leaching of Al 2 O 3.2H 2 O (or bauxite) with a heated and concentrated solution of sodium hydroxide. In this example, the concentrated NaOH dissolves the aluminium present in the bauxite whereas the impurities such as Fe 2 O 3, TiO 2, and SiO 2, are not dissolved by ...

function of naoh during leaching of gold ores. function of naoh during leaching of gold ores. To develop a fundamental understanding of cyanide heap leaching of lowgrade gold ores, with significant copper mineralization, two sets of column leach tests were operated under two different leaching …

 · Sodium hydroxide was used for pretreatment of the refractory gold–silver ore from the Akoluk deposit. The alkaline pretreatment process significantly improved the gold recovery from 49.3% to 85.4%. Hasab et al : Combining sulfide oxidation and gold leaching using chloride/hypochlorite solution

A mathematical model of cyanidation heap leaching of cupriferous gold ores which includes the speciation of all cyanide, cyanate, thiocyanate, hydroxide and sulfate complexes, and their corresponding copper and gold precipitates, was developed to facilitate the treatment of these complex ores. The concepts of back mixing and solution retention are represented by two fundamentally different ...

LEACHING GOLD-SILVER ORES WITH SODIUM CYANIDE AND THIOUREA UNDER COMPARABLE CONDITIONS By J. A. ~isele,'' A. E. ~unt,~ and D. L amps shire^ ABSTRACT There is currently mch interest in how extraction of gold and silver from ores with …

 · The timing of gold recovery from ore in a heap leach is a function of five factors: 1) The rate of gold dissolution. Coarse gold particles dissolve very slowly, and may not fully dissolve for ...

Secondly, the pretreated ore was leached under ultrasound. The leaching ratio of gold decreased with increasing of the ultrasound pretreatment time from 1 to 5 h and the NaOH concentration from 5 to 20 wt%. The ultrasound increased remarkably the leaching ratio of gold when the pretreated ore was subjected to ultrasound leaching.

 · scale as a pre-treatment to improve gold yields and reduce chemical consumption during gold cyanidation. In this study, the effect of initial cell concentration on the oxidation of pyritic gold ore was evaluated with four aerated bioreactors at 30 C with 10% pulp density and pH maintained at 1.4 with NaOH.

tions are an indication of oxygen demand during oxidation of oxidative treatment is conducted on the refractory gold ore or gold ores. The dissolution of sulphides results in high cyanide concentrate prior to gold recovery by a cyanide leaching process consumption with the formation of …

A method of recovering gold from carbon fines in a resin-in-leach process wherein the fines are contacted with an ion exchange resin, in the presence of a suitable lixiviant, to load gold onto the resin, eluting the gold from the resin using a suitable eluent and recovering the gold from a resulting eluate.

 · The cyanidation plants has been using sodium cyanide to dissolve the gold from the ore in order to recover the gold from the leaching solution. The formula is as follows: 2Au+4NaCN+O2+2H2O→2Na [Au (CN)2]+2NaOH+H2O2. 2Au+4NaCN+H2O2→2Na [Au (CN)2]+2NaOH. From the electrochemical reaction, it can be known that dissolving 1 gram of gold ...

The gold is recovered from this solution by electrowinning, zinc precipitation or refining technology such as the Mintek Minataur process. The eluted carbon may still contain various organic 48 2 4 4Au NaCN O H O NaAu CN NaOH+++ → + 22 2 The process design of gold leaching and carbon-in-pulp circuits

FIELD: metallurgy. SUBSTANCE: extraction method of gold from oxidised argillaceous gold-bearing ores involves grinding, sieving of ore, mixing of ore with binding substance, pelletising of ore so that pellets are obtained, formation of stock pile from the obtained pellets and heap leaching of gold by spraying of sodium cyanide solution so that solutions enriched as to gold are obtained.

Conducted a series of tests on leaching, during which gold and silver are extracted from the calcined product using aqueous bromine leaching agent. For the preparation of leaching agent part of the concentrate of example 1 (1.4 g) and 48% Hydrobromic acid (0.8 g) was introduced into a …

 · ICP analysis show that during the NaOH treatment, significant amount of Al dissolved. ... S. Reaction chemistry of gold leaching in thiourea solution for a Turkish gold ore…

The total consumption of NaOH in alkaline leaching is only 28% of that theoretically calculated under ... The treatment of refractory gold ores( or con- centrates) ... leaching. During alkaline leaching, the oxidation of arsenopyrite and pyrite( FeS2),

 · The role pH has in affecting gold leaching rates by cyanide and the functions of calcium hydroxide in cyanidation are as follow:. 1. For safety and to prevent loss of cyanide by hydrolysis. 2. To prevent loss of cyanide by the action of carbon dioxide in the air. 3. To decompose bicarbonates in mill water before using it in cyanidation.

Alkaline Oxidative Leaching of Gold-Bearing Arsenopyrite Ores. 2,4 h, and 2M NaOH solution in a 2-L autoclave. Cyanidation of the leach residues resulted in 90 to 93 pct Au and 60 to 80 pct Ag extractions, compared with only 5 and 15 pct, respectively, without the pretreatment.

ABSTRACT Carlin-type refractory gold deposits are complex bodies which only occur in certain regions such as the western United States, southwest China, and northwest Iran. It is important to investigate the most suitable treatment option for each deposit from the point of the mineralogical composition. The present study investigates the effect of atmospheric NaOH alkaline pretreatment on the ...

function of naoh during leaching of gold ores. Cyanide Leaching Of Gold Mine Engineer Com Gold Cyanide Solution Leaching Gold With Cyanide Since the 1890 s cyanide has been used to recover gold from gold bearing ores And today over 115 years later most of the worlds gold …

Intensive Cyanidation Reactors (ICR) are used primarily for the gold leaching of high grade concentrates such as gravity concentrates. While applications exist for low volume high grade refractory gold ores, operational costs make intensive cyanidation reactors …

A cyanide leaching test (Test 0) was carried out on the gold ore to determine the preg-robbing tendency of the raw material under investigation. Figure 1 shows that the raw material used was not preg-robbing. The gold concentration in the solution during cyanide leaching (Test 0) increased as a function of time up to 24 hours. This kinetic

oxidative leaching of gold-bearing arsenopyrite ores. Arsenic extraction was demonstrated to depend on the concentration of NaOH for a FeAsS ore containing 28.2%