recovery of gold from refractory ores zimbabwe

  • US4891060A

    The present invention relates to a process for the recovery of gold and in particular to a method for the recovery of gold from a refractory or non-refractory ore. Gold is found as the native metal widely distributed in minute traces in various minerals, such as certain quartz ores and certain alluvial gravels.

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  • HYDROMETALLURGICAL TECHNOLOGY FOR GOLD

    deterioration of the quality of gold-bearing ore. Since rich ores are gradually depleted, low-grade ores as well as those with more complex composition and concentrates come on stream (are used as raw materials). Therefore, the gold recovery from refractory gold-bearing raw materials becomes the most important problem.

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  • The Metallurgy of Cyanide Gold Leaching

    Oct 20, 2014Refractory Ores/Solid-Solution Gold: In some ores, Au can be locked inside the sulphide mineral matrix of the ore (so called solid solution), and the cost for the energy required to grind and liberate is simply too high to be viable. These are "refractory ores" and require a chemical, not simply physical, process to liberate gold from the

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  • Recovery of platinum group metals from oxide ores—TML

    The Great Dyke, Zimbabwe, contains over 800 million ounces of platinum and approximately 20 million ounces of rhodium. However, about 10% of the ore is oxidized and cannot be processed with current recovery methods. A conventional flotation-smelting process has been proposed to recover the platinum group metal (PGM) values from the sulfide ores.

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  • Ministry of Mines to resuscitate Kwekwe gold roasting

    The government has assumed responsibility of resuscitating Kwekwe refractory gold roasting plant with a view to realise $140 million from extracting gold trapped in dumps at the plant, a senior

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  • Recovery Refractory Resources

    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. Dr Chris Fleming, senior metallurgical consultant at

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  • Pretreatment with Ozone for Gold and Silver Recovery from

    In this work ozonization was studied as pretreatment for two Mexican refractory ores in order to increase the gold and silver extraction. Two methods for contacting ozone with the mineral were

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  • Gold extraction

    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

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  • OVERVIEW OF ZIMBABWE'S MINERAL RESOURCE

    • 7% of continents made up of the Archaean whereas about 60% of Zimbabwe's land surface comprises rocks of this important Era • granitic rocks locally enclosing remnants of volcano-sedimentary piles of Greenstone Belts.

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  • gold recovery from antimony ore stibnite

    Oct 01, 2000 Recovery of gold from refractory ores requires a pretreatment to liberate the gold particles from the host mineral. In particular, in the case of stibnite (Sb 2 S 3), the antimony (Sb) forms stable compounds with sodium cyanide (NaCN) during the cyanidation process; as a consequence, cyanide consumption is usually an oxidation step.

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  • GOLD IN ZIMBABWE

    and pyrite-solid solution gold atomically distributed in the crystal structure sulphide minerals •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

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  • Kwekwe roasting plant to reawaken

    Sep 16, 2015The roasting plant was established in 1937 by the then Government of Rhodesia to assist small and medium scale miners around Kwekwe in the processing of dumps or refractory gold ore. These dumps have an estimated 350 000 metric tonnes of ore and according to Peacocke and Simpsons Mineral Processors, they contain 97 220 ounces of gold worth $140 million at current prices.

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  • Cyanide Leaching Of Gold

    Generally, the recovery for cyanide leaching of sulfide or refractory ores is no better than 30%, which is not a worthwhile venture. The use of alkalies such as calcium oxide, will prevent the decomposition of cyanide in solution to form hydrogen cyanide gas.

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  • Characterization of refractory behaviour of complex gold

    Diagnostic leaching tests were also performed to shed light on the refractory characteristics of ore. The leaching tests show that the extraction of gold and silver is consistently low, i.e. ⩽47% and ⩽19.2%, respectively, over a leaching period of 24 h. Even fine grinding (e.g. 38 μm) does not improve the recovery of gold and silver.

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  • autoclave gold recovery plant

    Apr 19, 2013Autoclaving oxidizes the sulphide minerals and exposes the gold particles, improving gold recovery to 90%. Alternative Ore Processing | Newmont Mining Corporation. We use alternative gold recovery methods in some processing plants to Newmont treats refractory ore in two ways: by using an autoclave or a roaster.

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  • US5536297A

    Finally, the invention is directed to a process for the recovery of gold from a pressure oxidized slurry of a refractory sulfidic and refractory carbonaceous auriferous ore having preg-robbing characteristics due to the presence of organic carbon in which the oxidized ore slurry is mixed with a thiosulfate lixiviant to produce a leached slurry comprising a solid residue and a gold-bearing leachate, the leached slurry is

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  • The recovery of gold from refractory ores by the use of

    The recovery of gold from refractory ores by the use of carbon-in-chlorine leaching. 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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  • The Recovery of Gold from Refractory Ores with Some Recent

    Refractory gold ores have been the subject of intensive metallurgical study in order to achieve more efficient recovery of contained values and at the same time to minimise environmental impact. Considerable innovative gold processing technology was introduced in New Zealand last century, the most notable being the first successful commercialisation of the cyanidation process by

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  • GOLD EXTRACTION Gold without tears

    refractory ores gain in importance. Some 15-20% of current world gold production involves refractory ores that must be pre-treated prior to downstream recovery by cyanidation. Ores are refractory for many reasons but commonly because gold occurs as tiny inclusions or submicroscopic gold within a sulphide mineral matrix. This mineral matrix

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  • Leaching of a Gold Bearing Partially Roasted Sulphide

    Gold Recovery Estimation. where p stands for product. It means that the ratio between the gold determined in the leachate and average gold content in the ore well estimates gold recovery and there is no need to determine gold in residues. However, in the case of gold ores, the use of expression (1) is frequently a must.

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  • Electro

    Acta Chim. Slov. 2007, 54, 907–911 909 Shah et sl.: Electro-Recovery of Gold (III) from Aqueous Solutions and Refractory, The best recovery of 29.1% gold with a standard de-viation value of 0.4 occurs at an optimum potential of 2.8 V, with shinning and better metallic characteristics.

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  • high pressure oxidation of refractory gold minerals

    4 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.

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  • Mine sits on 4,8 million ounces of gold

    Aug 22, 2018"Since the closure of the Roasting Plant in Kwekwe there has been no gold production from refractory ores. This marks a new phase as Zimbabwe starts producing gold from refractory ores.

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  • zimbabwe refractory gold deposits

    -Recovery Of Gold From Refractory Ores Zimbabwe-recovery of gold from refractory ores zimbabwe the recovery of precious metals from refractory ores has previously received arsenic refractory gold the, Process Parameters for Bio-oxidation of Sulphur in,

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  • The reasons of gold refractory, Gold ore classification

    Nov 28, 20162. Pyrite, Arsenical pyrite, realgar, orpiment, and Arsenic antimony sulfur gold ore. The most of refractory ore is gold bearing sulfide. Sulfide iron ore includes many kinds of pyrite and

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  • GOLD RECOVERY The golden age

    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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