function of naoh during leaching of gold ores

  • Gold and copper leaching from gold-copper ores and ...

     · The following sections cover the gold and copper extraction from ores and gold, silver and copper extraction form a concentrate. 3.2. Gold-copper ores: gold-copper oxides. The gold extraction from leaching gold-copper oxides ore, containing 12.9 ppm gold and 0.04% copper, has been studied. The copper in such ore is present at nuisance levels ...

  • The Metallurgy of Cyanide Gold Leaching – An Introduction ...

     · With lower gold grades beneficiation (usually flotation) is often used ahead of leaching to increase the grade of Au and reduce the quantity of ore to be leached. Nature of Gold: The surface of a gold particle will typically be dissolved at a rate of around 0.2-0.5 µm of surface depth per hour in a cyanide leach.

  • Dissolution Behavior and Mechanism

     · Minerals 2017, 7, 196 4 of 12 3. Results and Discussion 3.1. Leaching Tests When the alkali leaching temperature was increased from 393 K to 513 K, the ASi and TSi increased (Figure2a). In this test, the concentration of NaOH solution was 3 mol/L, and leaching time was 1 h.

  • Processing Gold Ores Using Heap Leach-Carbon Adsorption ...

    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.

  • Ultrasound-intensified Leaching of Gold from a Refractory Ore

    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.

  • Alkaline Pressure Oxidation of a Gold-Bearing Arsenopyrite ...

    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 ...

  • Effect of Pretreatment on Leaching Primary Copper Sulfide ...

    Minerals 2018, 8, 1 3 of 14 2. Materials and Methods 2.1. Ore An industrial copper sulfide ore from the Antofagasta Region, Chile was used. The ore was crushed and milled to obtain a particle size below 150 m, with a P80 of 94.01 m, which was determined with a Microtrac S3500 particle size analyzer (Microtrac Inc., Montgomeryville, PA, USA).

  • function of naoh during leaching of gold ores by cyanidation

    A Method for Leaching or Dissolving Gold from Ores or Precious … & 0183;& 32;NaOH must be present as neutralizer to maintain alkaline conditions at a constant pH of 11. metallurgical leaching of gold ores by cyanidation or in the aqua regia process used for the recovery of secondary gold from electronic and precious scraps the

  • (PDF) The Use of Oxygen in Gold Cyanidation | Wesley ...

    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 …

  • Sodium Hydroxide Extraction From Caustic Leaching …

    concentration would have a negative impact if the added NaOH were routed to the LAW stream; that is, the LAW mass would be significantly increased. To enable the use of higher hydroxide concentrations during sludge leaching, without adversely affecting the LAW stream, we have proposed to recycle the NaOH by using a liquid-liquid extraction method.

  • Gold cyanidation

    Gold cyanidation (also known as the cyanide process or the MacArthur-Forrest process) is a hydrometallurgical technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex is the most commonly used leaching process for gold extraction.. Production of reagents for mineral processing to recover gold, copper, zinc and silver represents ...

  • sketches & tables

    effective technique for well leachable high grade gold ores is agitation leaching. Thereby an ore pulp with grain sizes of < 100 microns is permanently agitated during its leaching in special tanks (e.g. Pachuca tanks). The leaching period is generally less than 24 hours. The gold …

  • (PDF) Gold Extraction and Recovery Processes For Internal ...

    Modeling of heap leaching of gold by cyanidation A mathematical model for heap leaching of gold ores by cyanidation was developed by Sanchez-Chacon and Lapidus in 1997 which describes gold heap leaching as a function of the mass transport steps involved, employing a rigorous kinetic expression to describe gold cyanidation [7].The model ...

  • Leaching Gold-Silver Ores With Sodium Cyanide and Thiourea ...

    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 …

  • Adsorption behaviour of copper and gold glycinates in ...

    gold-copper ores, these ores are conventionally first acid leached prior to neutralisation and cyanidation. However, being an alkaline leach, glycine leaching of gold ores is less susceptible to acid consuming gangue and co-leaching of Fe, Mn, Mg and Al (Eksteen and Oraby, 2015; Tanda et al., 2017). Glycine therefore allows the leaching of

  • Sodium Hydroxide Extraction From Caustic Leaching Solutions

    concentration would have a negative impact if the added NaOH were routed to the LAW stream; that is, the LAW mass would be significantly increased. To enable the use of higher hydroxide concentrations during sludge leaching, without adversely affecting the LAW stream, we have proposed to recycle the NaOH by using a liquid-liquid extraction method.

  • Leaching Process

    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 cyanide in leaching

    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 …

  • Use of ferricyanide for gold and silver cyanidation

    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

  • Atmospheric alkaline pre-oxidation of refractory sulphide ...

    Four iron-sulphide-containing gold ores from the White Mountain mine in the Jilin Province, China were studied to examine the benefits of using oxidative treatment prior to conventional cyanidation to leach gold. This pre-treatment consisted of bubbling air into an ore/water mixture for eight hours while adding enough caustic sodium hydroxide to maintain a pH of 11 throughout the test. Three ...

  • A Method for Leaching or Dissolving Gold from Ores or ...

    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 hazardous chemicals such as sodium cyanide or aqua regia. These chemicals represent health and safety risks for workers and a serious threat for the

  • Alkaline Oxidative Leaching of Gold-Bearing Arsenopyrite ...

    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.

  • L.R. Freitas, R.B.E. Trindade and T. Carageorgos

    extraction of gold. ln addition, experimental results of a study on lhiosulphate leaching of gold-copper ores from the lgarape Bahia Mine (CVRD, Brazil) are reported. While cyanide should remain as the first choice for lhe hydrometallurgy of most gold ores, lhe results of this study ~ndicate that thiosulphate may he ao attractive and

  • A Method for Leaching or Dissolving Gold From Ores or ...

     · 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 …

  • EP0806487A1

    A hydrometallurgic and electrochemical process for processing sulfur antimony ores and residues is disclosed, the end products from which are electrolytic antimony and elemental sulfur. The concentrate of sulfur antimony ore, leached with a solution of caustic alkali according to the known techniques dissolves, as sulfur salts as much Sb as possible, whilst the other heavy and precious metals ...

  • Function Of Naoh During Leaching Of Gold Ores

    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 …

  • Alkaline oxidative leaching of gold-bearing arsenopyrite ores

    Leaching of a high-grade arsenopyritic ore containing, in percent, 28.2 As, 25.3 Fe, 19.9 Total s, and 1.0 Sb and, in troy ounces per short ton, 1.6 Au and 5.5 Ag resulted in > 90 pct as extraction at 100 deg c, 40 psig o2, 4 h, and 2 m naoh solution in a 2-l autoclave.

  • CIL Gold Loss Characterization within Oxidized Leach Tails ...

    A double refractory gold ore contains gold particles locked in sulphides, solid-solution in arsenopyrite, and preg-robbing material such as carbonaceous matter, and so on. The diagnostic leach test (DLT) and preg-robbing (PR) approaches are widely used to investigate the occurrence and the distribution of refractory gold. DLT serves to qualitatively evaluate the gold occurrences within the ore.

  • Simultaneous Removal of S and As from a Refractory Gold ...

     · S and As are common impurities in refractory gold ores and must be removed before gold extraction. Thermodynamic analyses show that it is possible to simultaneously remove S and As by an O2-enriched single-stage roasting, which is confirmed with experimental results from roasting of a gold refractory ore. The range of optimal O2 requirement is narrow and varies with the S and As …

  • What Are Commonly Used Gold Recovery Chemicals? | CNFREE

     · The heap leaching method is mainly suitable for low-grade gold ore recovery, with the average grade of gold ore is 0.8-1.5g/t. Heap leaching gold recovery process is to first crush the ore to certain particle size (-15mm) and then convey it to the storage hopper, adding gold ore, lime and binder according to the specified amount, mixing them ...

  • The Leaching Characteristics of Chromite Ore Processing ...

     · To this end, leaching with different extraction solutions was studied as a function of time. The DI water, 0.1M NaOH and 1M NaOH leaching results were similar with around 47% of the total available Cr(VI) leaching out up to 480 hours. 1M and 0.1 M Na 2 HPO 4 could leach out 58% and 51% of total Cr(VI) at 48 hours, respectively.

  • Frontiers | Selective Pre-leaching of Tellurium From ...

     · With a telluride-type gold ore flotation concentrate as the research object, the Na2S + NaOH collaborative leaching process was applied to selectively separate tellurium before the cyanide leaching of gold and silver. The effects of process parameters including the type of leaching agent, the amount of leaching agent, liquid-solid ratio, leaching temperature, and leaching time on the leaching ...

  • The total consumption of NaOH in alkaline leaching is only 28% of that theoretically calculated under ... However, the gold leaching rate by thiosulfate leaching for 24 h is in- creased to 91. 7% from 0 — 3. 2% by ultra-fine grinding without the pretreatment. ... The treatment of refractory gold ores( or con- centrates) attracts more concerns ...

  • Arsenic Pyrite Gold Extraction by Alkaline Leaching Oxidation

     · The alkaline oxidative leach pretreatment for gold-bearing arsenopyrite ores uses mild conditions, and the leach residue requires no washing or pH adjustment before cyanidation. By using 2M NaOH, 100° C, 40 psig O2, 10 pct solids, and 4 h, more than 90 pct of the arsenic was extracted from the high-grade ore.

  • 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. The procedure was further tested by leaching a low-grade gold ore and a bulk sulfide flotation concentrate prepared from it.

  • Selective Pre-leaching of Tellurium From Telluride-Type ...

     · 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

  • Gold leaching in cyanide-starved copper solutions in the ...

    the pH of the leach solutions to 12.5 using NaOH; (step 3) adding 0.85 g/L glycine to the leach solution and re-adjusting pH to 11.5. The gold dissolution from leaching a pure gold disc (2.27 cm2) after 2 h, for each step, is shown in Fig. 2. It can be seen that increasing the pH of cuprous cyanide solutions (step 2) enhances the dissolution of ...

  • Optimizing and evaluating the operational factors ...

     · This research was carried out on Aghdareh gold ore. The Aghdareh mine and gold processing plant is located 32 km from Takab city in the western Azerbaijan province, Iran, at 46°58′30′′N and 36°39′29′′E. The grade of gold ore is 3 ppm. Also, cyanide leaching is used to process gold in the Aghdareh mine . The main problem in ...

  • How to Use Bleach on Gold Ore to Remove Gold | Sciencing

     · 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 ...

  • The process design of gold leaching and carbon-in-pulp ...

    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

  • Procedure for extraction of gold from refractory clay ore

    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.

  • ph modifiers for tennantite flotation

    Froth flotation process with pH modification ARRMAZ . What is claimed is 1. A process for increasing a flotation recovery with improved concentrate grade of desired minerals in alkaline froth flotation processes of oxide and semisoluble ores, the method comprising, instead of using traditional pH modifiers, including caustic soda, soda ash, lime and ammonia for pH adjustment and using soda ash ...

  • Pretreatment of a refractory arsenopyritic gold ore using ...

     · An arsenopyrite refractory ore was pretreated with NaOH to increase gold extraction. After pretreatment, gold and silver were leached with copper ammonium thiosulfate solution. Thiosulfate leaching of the as-received ore extracted only 21% and 29% of silver and gold, respectively. Up to 81% of the gold and 50% of the silver were recovered after ...