Bacterial Oxidation of a Refractory Pyrite-arsenopyrite-gold Ore Concentrate PDF Download
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Author: Soumitro Nagpal
Publisher:
ISBN:
Category : Bacterial leaching
Languages : en
Pages : 264
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Book Description
Author: Soumitro Nagpal
Publisher:
ISBN:
Category : Bacterial leaching
Languages : en
Pages : 264
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Book Description
Author: Douglas E. Rawlings
Publisher: Springer Science & Business Media
ISBN: 3662061112
Category : Science
Languages : en
Pages : 302
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Book Description
Biomining is the use of microorganisms in the recovery of metals from ores. During bioleaching, metals such as copper, nickel or zinc are oxidized through microbial action from the water-insoluble sulfide to the soluble sulfate forms. Although gold is inert to microbial action, microbes can also be used in gold recovery from certain types of ores because as they oxidize the ore, they open up its structure, thereby allowing a gold-solubilizing agent such as cyanide to penetrate the ore. The book describes several industrial bioleaching and biooxidation processes as well as the underlying theory and biology of the microbes involved.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The liberation of refractory gold from sulphides during bacterial oxidation was investigated using arsenopyrite and pyrite crystals isolated from a refractory Barberton gold ore. Polished sections of the crystals were prepared and the mode of occurrence of gold within these sulphides was determined, using a scanning electron microscope (SEM) and an electron microprobe. It was found that the arsenopyrites and pyrites are chemically zoned, due to alternating enrichment and depletion in the As-content. The submicroscopic gold is heterogeneously distributed in the arsenopyrite and is specifically enriched in zones with a relatively moderate Fe-content, a high As-content and a low S-content. The As-rich zones in the pyrite are also enriched in submicroscopic gold. Particulate gold occurs as inclusions within arsenopyrite and pyrite mainly at the contacts between different zones. Polished sections were suspended in the bacterial leach pulp in an air-stirred vessel for various periods of time. The effects of the sulphide oxidation were monitored by observations of the leached sections under both an optical microscope and a SEM. The As-rich zones in both arsenopyrite and pyrite crystals were preferentially and rapidly oxidized. Structural deviations in the sulphide lattices, such as zone contact, cracks, dislocation and contacts between different sulphide generations, were also sites of initial bacterial attack. These results show that the composition of the sulphides plays a fundamental role in determining the sites and rates of bacterial oxidation. Due to this preferential oxidation of high gold-bearing areas in the sulphides, large amounts of particulate and submicroscopic gold will be liberated during the very early stages of sulphide oxidation. The As-poor zones in both the arsenopyrite and pyrite crystals were oxidized during the later stages of bacterial oxidation, which will result in the slower liberation of the remaining gold.
Author:
Publisher: SME
ISBN: 0873352661
Category : Hydrometallurgy
Languages : en
Pages : 1201
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Book Description
Author: Mike D. Adams
Publisher: Elsevier
ISBN: 0444636706
Category : Science
Languages : en
Pages : 1050
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Book Description
Gold Ore Processing: Project Development and Operations, Second Edition, brings together all the technical aspects relevant to modern gold ore processing, offering a practical perspective that is vital to the successful and responsible development, operation, and closure of any gold ore processing operation. This completely updated edition features coverage of established, newly implemented, and emerging technologies; updated case studies; and additional topics, including automated mineralogy and geometallurgy, cyanide code compliance, recovery of gold from e-waste, handling of gaseous emissions, mercury and arsenic, emerging non-cyanide leaching systems, hydro re-mining, water management, solid–liquid separation, and treatment of challenging ores such as double refractory carbonaceous sulfides. Outlining best practices in gold processing from a variety of perspectives, Gold Ore Processing: Project Development and Operations is a must-have reference for anyone working in the gold industry, including metallurgists, geologists, chemists, mining engineers, and many others. - Includes several new chapters presenting established, newly implemented, and emerging technologies in gold ore processing - Covers all aspects of gold ore processing, from feasibility and development stages through environmentally responsible operations, to the rehabilitation stage - Offers a mineralogy-based approach to gold ore process flowsheet development that has application to multiple ore types
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
A mechanistic model is derived for the non-linear relationship between the release of gold and the percentage of sulphide oxidized during the bacterial leaching of mixed pyrite and arsenopyrite concentrates. The original ratio of pyrite to arsenopyrite, the ratio of the rate constants for their breakdown, and the distribution of gold between these two minerals are the parameters used for the fitting of curves to the experimental data. During bacterial leaching, cylindrical pores develop along weaknesses in the sulphide lattice, which are therefore preferred sites of bacterial corrosion. If the gold is in a particulate form and preferentially associated with such structural weaknesses, the release of gold occurs at an accelerated rate that does not conform to the numerical model.
Author: John C. Yannopoulos
Publisher: Springer Science & Business Media
ISBN: 1468484257
Category : Technology & Engineering
Languages : en
Pages : 285
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Book Description
The history of gold begins in antiquity. Bits of gold were found in Spanish caves that were used by Paleolithic people around 40,000 B.C. Gold is the "child of Zeus," wrote the Greek poet Pindar. The Romans called the yellow metal aurum ("shining dawn"). Gold is the first element and first metal mentioned in the Bible, where it appears in more than 400 references. This book provides the most thorough and up-to-date information available on the extraction of gold from its ores, starting with the miner alogy of gold ores and ending with details of refining. Each chapter con cludes with a list of references including full publication information for all works cited. Sources preceded by an asterisk (*) are especially recom mended for more in-depth study. Nine appendices, helpful to both students and operators, complement the text. I have made every attempt to keep abreast of recent technical literature on the extraction of gold. Original publications through the spring of 1989 have been reviewed and cited where appropriate. This book is intended as a reference for operators, managers, and designers of gold mills and for professional prospectors. It is also designed as a textbook for extractive metallurgy courses. I am indebted to the Library of Engineering Societies in New York, which was the main source of the references in the book. The assistance of my son, Panos, in typing the manuscript is gratefully acknowledged.
Author: Mike D. Adams
Publisher: Elsevier
ISBN: 0080459080
Category : Technology & Engineering
Languages : en
Pages : 1077
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Book Description
The gold processing industry is experiencing change. As free-milling and oxide ores become depleted, more complex polymetallic and refractory ores are being processed, coupled with increasing pressure for stricter environmental compliance. Recent years have also seen a steady reduction in mineral processing and metallurgy graduates and a gradual loss of older operating experience. A contribution to documenting current and future best practice in gold ore processing seems timely.The focus of this volume is on advances in current gold plant operation, from conception to closure; chapters also cover innovations at the bench and pilot-scale level that would be expected to find commercial application at some stage. Sufficient coverage is also given to the chemistry and engineering aspects. The general principle behind the structure of the volume is that of flowsheeting based on unit operations and applied to a mineralogical classification of gold ore types. From concept to closure, this book covers all unit operations, mineralogies and processes that are relevant to dealing with today's complex orebodies.Practical experience is vital to the successful development, operation and closure of any operation. The 42 chapters have been contributed by a total of 66 authors and co-authors who are experts from countries spanning the globe, and representing exhaustive practical knowledge covering many disciplines relevant to gold processing.* Current best practice as elucidated by a select panel of experts in the field* Innovations at the bench and pilot-scale level that would be expected to find commercial application at some stage* Mineralogical-based approach to flowsheeting
Author: Edgardo R. Donati
Publisher: Springer
ISBN: 9789048174027
Category : Technology & Engineering
Languages : en
Pages : 0
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Book Description
The application of microbiological methods to the extraction of metals from minerals is supported by several bioleaching and biooxidation processes operating in different sites over the world. This book details the basic aspects of the process with special emphasis on recent contributions regarding the chemical and microbial aspects of the bioleaching process and the use of microorganisms in the treatment of complex ores and concentrates.
Author: Katherine Malatt
Publisher:
ISBN:
Category :
Languages : en
Pages : 528
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Book Description
This study sought to determine the rates of ferric sulflate oxidation and bacterial oxidation of arsenopyrite. Ferric oxidation of arsenopyrite revealed unusual temperature related behaviour with the fastest leaching rate observed at 50οC above this the mineral surface became covered by a jarosite phase which hindered the reaction. Use of a flat disk of arsenopyrite allowed surface area based rates to be determined. These were similar to those for sized slurries under similar conditions. The rates of bacterial and ferric oxidation of arsenopyrite were also found to be comparable. This is further evidence for the "indirect" mechanism of bacterial leaching.
