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recovery of gold from refractory ores zimbabwe

gold refractory ores microwave assisted recovery. Huang (2000) and Huang and Rowson (2000) also investigated the effect of microwave irradiation on gold recovery from refractory ore obtained from Lihir Gold Mine, Papua New Guninea. The ore was sized between and 16 mm and was irradiated for a period between 0 and 70 min in either a monomode or ...

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GOLD IN ZIMBABWE - SAIMM

•Naturally occurring active carbon which results in preg- robbing. Gold may be exposed to cyanide solution for leaching but recovery is inhibited by the gold getting adsorbed onto carbon •Double refractory are concentrates or ores in which gold is in solid solution and also there is active carbon REFRACTORINESS OF GOLD ORES

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Govt to revive gold roasting plant - NewsDay

Roasting is the process used to extract gold from the refractory gold ore. According to scientists, roasting is the only commercialised process in Zimbabwe for the pre-treatment of refractory gold...

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recovery of gold from refractory ores zimbabwe

recovery of gold from refractory ores zimbabwe. Zim looking for firms interested in treating calcine dumps Know More . Zim looking for firms interested in treating calcine dumps to recover 4 set up a refractory gold recovery processing of refractory gold ores... An acidic pressure oxidation pre Know More. An acidic pressure oxidation pre-treatment of refractory gold GOLD CONCENTRATES FROM

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recovery of gold from refractory ores zimbabwe

gold refractory ores microwave assisted recovery. Huang (2000) and Huang and Rowson (2000) also investigated the effect of microwave irradiation on gold recovery from refractory ore obtained from Lihir Gold Mine, Papua New Guninea. The ore was sized between and 16 mm and was irradiated for a period between 0 and 70 min in either a monomode or ...

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The recovery of gold from refractory ores by the

In this environment, the refractory ore is altered, and gold is extracted and then recovered on activated carbon. With highly carbonaceous ores, CICL achieved a higher recovery than with primarily sulfidic refractory ores. Basic cyanide amenability testing of two carbonaceous ores

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GOLD IN ZIMBABWE - SAIMM

•Naturally occurring active carbon which results in preg- robbing. Gold may be exposed to cyanide solution for leaching but recovery is inhibited by the gold getting adsorbed onto carbon •Double refractory are concentrates or ores in which gold is in solid solution and also there is active carbon REFRACTORINESS OF GOLD ORES

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recovery of gold from refractory ores zimbabwe

recovery of gold from refractory ores zimbabwe. Zim looking for firms interested in treating calcine dumps Know More . Zim looking for firms interested in treating calcine dumps to recover 4 set up a refractory gold recovery processing of refractory gold ores... An acidic pressure oxidation pre Know More. An acidic pressure oxidation pre-treatment of refractory gold GOLD CONCENTRATES FROM

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Refractory gold ores: Challenges and opportunities

Refractory gold reserves, which require more sophisticated treatment methods in order to achieve oxide-ore recovery rates, correspond to 24 percent of current gold reserves and 22 percent of gold resources worldwide (Exhibit 1). Despite offering a higher grade, these ores can only be processed using specific pretreatment methods such as ultrafine grinding, bio oxidation, roasting, or pressure oxidation (POX).

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US5536297A - Gold recovery from refractory

Gold is recovered from the gold-bearing leachate by cementation, adsorption on an adsorbent, or cyanidation. A process for recovering gold in which an ore slurry of refractory sulfidic and...

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Treatment of carbonaceous refractory gold ores

01/01/1991  Free milling ores are easy to treat. Gold in such ores is recovered by gravity separating techniques or direct cyanidation. Refractory gold ores, on the contrary, are difficult to treat and require pre-treatment prior to cyanidation. The refractoriness of gold is a consequence of ore mineralogy. Refractory gold ores have the following characteristics: (1) gold in intimate association with and locked

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Recovery Refractory Resources - SGS

refractory gold ore is gold- containing ore that is resistant to recovery by direct cyanidation and carbon adsorption processes. More specifically, it is an ore that has a gold recovery rate of less than 80% when direct cyanidation is applied to it.

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Gold extraction - Wikipedia

A "refractory" gold ore is an ore that has ultra fine gold particles disseminated throughout its gold occluded minerals. These ores are naturally resistant to recovery by standard cyanidation and carbon adsorption processes. These refractory ores require pre-treatment in order for cyanidation to be effective in recovery of the gold. A refractory ore generally contains sulfide minerals, organic carbon, or both.

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Treatment of carbonaceous refractory gold ores

Refractory ores, on the other hand, are difficult to treat and require pre-cyanidation processes to liberate the gold. Underlying the difficulty of processing refractory gold ores is their mineralogy. This type of ore may have, (1) gold in intimate association with and locked in sulphide minerals, (2) gold associated with carbonaceous matter capable of adsorbing aurocyanide and (3) gold in solid solution with other minerals.

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The recovery of gold from refractory ores by the

In this environment, the refractory ore is altered, and gold is extracted and then recovered on activated carbon. With highly carbonaceous ores, CICL achieved a higher recovery than with primarily sulfidic refractory ores. Basic cyanide amenability testing of two carbonaceous ores achieved recoveries of only 5.5% and 46%. With CICL treatment, recoveries on carbon were 90% and 92%.

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Recovery of gold from refractory gold ores:

Recovery of gold from refractory gold ores: Effect of pyrite on the stability of the thiourea leaching system. Hong Qin 1), Xue-yi Guo 1,2), , , Qing-hua Tian 1,2), , , and ; Lei Zhang 1) Corresponding authors: Xue-yi Guo E-mail: [email protected] Qing-hua Tian E-mail: [email protected] 1. School of Metallurgy and Environment, Central South University, Changsha 410083, China ; 2. National ...

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The recovery of gold from refractory ores by the

Recently, the U.S. Bureau of Mines examined the recovery of gold by chlorination of refractory carbonaceous and sulfidic ores, comparing various treatment methods in which a ground ore pulp is contacted with chlorine gas and activated carbon is added to the pulp for a carbon-in-chlorine leach (CICL). The objective of this research was to demonstrate the basic feasibility of CICL technology.

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US5536297A - Gold recovery from refractory

Gold is recovered from the gold-bearing leachate by cementation, adsorption on an adsorbent, or cyanidation. A process for recovering gold in which an ore slurry of refractory sulfidic and...

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Recovery Refractory Resources - SGS

refractory gold ore is gold- containing ore that is resistant to recovery by direct cyanidation and carbon adsorption processes. More specifically, it is an ore that has a gold recovery rate of less than 80% when direct cyanidation is applied to it.

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Pyrometallurgical Recovery of Gold From

The problem concerning effective processing of gold ledge ores extremely refractory to loosening has been considered. [1]. Among gold ledge ores in Central Kazakhstan, ores from the Sayak-4 gold-arsenic-cobalt deposit discovered in 1950s have not been processed until the present as they are extremely refractory to loosening and beneficiation. [2, 3]. This papers is devoted to experimental ...

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Process for the recovery of gold from refractory

Process for the recovery of gold from refractory ores by pressure oxidation . United States Patent 4552589 . Abstract: A process for recovering precious metals from a refractory ore by forming a slurry which is heated to a temperature in excess of about 150° C. at an oxygen partial pressure in excess of about 10 psia for an effective amount of time to form a partially oxidized slurry which is ...

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Treatment of Refractory Gold Ores SpringerLink

Problem ores that yield low (say less than 80%) gold recovery by cyanidation when “normally ground” are defined as refractory. The term, as well as the technical methods used to treat such ores, are relatively new. Rose and Newman’s very comprehensive book,

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Gold Recovery And How To Choose The Right

A more technical definition is that you are able to recover over 90% of the gold by a conventional gravity-cyanidation process with low reagent consumption. Free-milling gold can be further classified into low grade and high grade which helps determine the most economical and optimal gold recovery method. Low Grade. Low grade free-milling gold deposits contain less than 1 g/t of gold. This low grade ore is

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Refractory Gold SGS

There are two important mechanisms by which gold recovery is limited through chemical interference. The first happens when there are minerals in the ore that consume cyanide or oxygen - the two essential ingredients for effective gold dissolution. In this case, the simplest route is to increase the concentrations of cyanide and oxygen until the consuming species has reacted away to completion, but this is often

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Recovery of gold from refractory gold ores:

Recovery of gold from refractory gold ores: Effect of pyrite on the stability of the thiourea leaching system. Hong Qin 1), Xue-yi Guo 1,2), , , Qing-hua Tian 1,2), , , and ; Lei Zhang 1) Corresponding authors: Xue-yi Guo E-mail: [email protected] Qing-hua Tian E-mail: [email protected] 1. School of Metallurgy and Environment, Central South University, Changsha 410083, China ; 2. National ...

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The recovery of gold from refractory ores by the

In this environment, the refractory ore is altered, and gold is extracted and then recovered on activated carbon. With highly carbonaceous ores, CICL achieved a higher recovery than with primarily sulfidic refractory ores. Basic cyanide amenability testing of two carbonaceous ores achieved recoveries of only 5.5% and 46%. With CICL treatment, recoveries on carbon were 90% and 92%.

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Process for the recovery of gold from refractory

The partial oxidation which occurs in the autoclave increases the recovery of gold from particularly refractory ores in a relatively short time while reducing the consumption of expensive cyanide. Thus, the present invention provides a process by which refractory ores, which may contain both carbonaceous and sulfur-bearing compounds, may be economically treated for the recovery of gold.

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(PDF) Pretreatment with Ozone for Gold and Silver

The recovery of gold from refractory sulfidic-carbonaceous ores after roasting pretreatment was studied. With the addition of an oxygen-containing gas (e.g., air or oxygen-enriched air), sulfides...

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Gold recovery: Effect of ozonation on refractory gold ores ...

Cyanidation has been the standard method used to leach gold ore and recover gold since 1890 (Adams, 2016). As free milling ores are depleting, the focus has shifted to gold ores that do not yield economic recoveries after conventional cyanidation and these ores are classified as refractory ores. An ore can be

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An acidic pressure oxidation pre-treatment of

Roasting is the only commercialised process in Zimbabwe for the pre-treatment of refractory gold feedstocks for the subsequent cyanidation leaching. This process results in only about 75% gold recovery and is characterised by high gold values in the residue. A pressure oxidation process in an autoclave has been evaluated as an alternative. The process resulted in substantially higher gold recoveries (>90%)

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GOLD RECOVERY The golden age - min-eng

refractory gold ores are sulphidic in nature. This means that flotation is invariably the first process option to consider. This is relatively straight forward and achieves high gold recovery. The higher the gold to sulphur ratio the better in terms of downstream processing options. For refractory gold ores gravity recovery is usually poor and of little benefit.

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17 - Flotation of Gold Ores - Aalto

Flotation of Gold Ores 17.1 INTRODUCTION The recovery of gold from gold-bearing ores depends largely on the nature of the deposit, the mineralogy of the ore and the distribution of gold in the ore. The methods used for the recovery of gold consist of the following unit operations: 1. The gravity preconcentration method, which is used mainly for recovery of gold from

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PRESSURE OXIDATION OF REFRACTORY GOLD ORES: THE

Pressure oxidation is employed to liberate gold and silver in refractory sulfide concentrates often and ores. The main pressure oxidation products from iron sulfide minerals are sulfuric acid (and metal sulfates) and hematite. Depending on the conditions within the autoclave, acid containing iron compounds can be formed. Such compounds include basic iron sulfate (BFS) and jarosites.

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Gold Extraction Recovery Processes

Gold Recovery. Gold recovery comprises similar stages to the processing of most ores. First, the valuable minerals are separated from the gangue through concentration. The final concentrate is obtained by repeated processing and is smelted or leached in order to get a Dore bar. In generals, the concentration of gold includes three stages: roughing, cleaning and scavenging. The reason of concentration is to

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