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The Recovery Of Gold From Refractory Gold Concentrates And Calcine Leach Residues By A Pyrometallurgical Procedure
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Book Synopsis The Recovery of Gold from Refractory Gold Concentrates and Calcine-leach Residues by a Pyrometallurgical Procedure by :
Download or read book The Recovery of Gold from Refractory Gold Concentrates and Calcine-leach Residues by a Pyrometallurgical Procedure written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A procedure is described whereby gold-containing calcined concentrates and leach residues from refractory gold ores are smelted with carbon to form a small amount of metal. The gold is liberated upon smelting, and is collected in the molten metallic phase, which is easily separable from the slag. The metallic phase consists of approximately 1 to 15 per cent (by mass) of the material after smelting, and the gold content is generally upgraded by a factor of greater than 6 compared with that of the original roasted material. Recoveries better than 95 per cent have routinely been achieved. The quenched metal contains predominant Fe-Ni alloy, as well as minor Fe sulphides and Cu-Fe sulphides. Trace amounts of Fe-Ni arsenide and Au-Cu alloy are also present. The gold content of the metallic phase can be increased further by oxidation of the hot metal in the presence of silica or slag. This will reduce the amount of metal, and will concentrate the gold in a smaller volume. The metallic phase can then be treated hydrometallurgically to recover the nickel and the gold.
Book Synopsis The Pyrometallurgical Recovery of Gold from Leach Residues by :
Download or read book The Pyrometallurgical Recovery of Gold from Leach Residues written by and published by . This book was released on 1989 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Attempts were made to recover the gold from leached calcine residues supplied by two mines in the Barberton area. The process used involved the smelting of the residues in a transferred plasma-arc furnace, and the recovery of the gold in a suitable collector held in the hearth of the furnace. Iron was used as a collector in the first instance, and charges of 10 kg of residue were smelted. While discard slags with gold contents of typically less than 1 g/t were produced, the recovery of gold in the iron (determined by the leaching of the iron produced in each campaign and analysis of the residue), was found to be low, ie, about 20 per cent and less. The overall accountability for gold, calculated from the gold content of the slags produced, the residue left in the furnace, and the iron collector, was also poor, ie, less than 30 per cent. There were indications that gold was lost through evaporation because of the high temperature at which the process had to be run to keep the collector molten. Although it was not possible to collect all the fume that was generated during the smelting operation, a sample of fume that was obtained had a gold content of 93 g/t. The major component of this fume was magnetite. The collection of gold in sulphide and speiss when gold-bearing flotation concentrate was smelted with leached calcine residue was more successful. In one campaign, where the collector consisted mainly of speiss, 90 per cent of the gold was recovered. Most of the remaining gold was contained in the residue that was recovered from the hearth of the furnace. Although carbon was added to reduce the hematite contained in the residue to wustite, the addition did not prevent the oxidation of the greater proportion of the matte. Because of the oxidation of the sulphide, it was necessary to add flotation concentrate in a quantity equivalent to between 24 and 36 per cent of the mass of the leached calcine residue in each of the two campaigns that were mounted. It is recommended that further work should be conducted on the collection of gold from the dust stream and on the collection of gold in matte and speiss.
Book Synopsis Improved Recoveries of Gold from Auriferous Calcines and Pyrites by Fine Milling by :
Download or read book Improved Recoveries of Gold from Auriferous Calcines and Pyrites by Fine Milling written by and published by . This book was released on 1984 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultra-fine milling of gold-bearing calcines prior to leaching in cyanide is a method that will lead to higher gold recoveries than at present. The economic implications are better for calcines than emanate from refractory ores since they contain more occluded gold. Milling to between 80 and 90 per cent finer than 11 um resulted in 36 per cent more gold being extracted from the calcine residues originating from non-refractory gold ores, whereas 40 per cent more gold was extracted from those originating from refractory ores. For gold-bearing pyrite concentrates, ultra-fine milling resulted in improved gold extractions, but more work on the optimization of the leaching conditions is required. Costs are not available for the ultra-fine grinding of calcines and pyrites since this technique is not currently employed on a plant. The recovery of gold from the solutions produced by the leaching of finely milled calcine residues and pyrite concentrates requires some consideration. Problems are likely if activated carbon is used in this treatment because of blockage of the carbon micropores by fine calcine or pyrite that is generated in the milling step.
Book Synopsis The Recovery Of Gold From Secondary Sources by : Syed Sabir
Download or read book The Recovery Of Gold From Secondary Sources written by Syed Sabir and published by World Scientific. This book was released on 2016-06-29 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: New discoveries of the properties of gold at a nanoscale, and its effective use in modern technologies, have been driving a virtual 'gold rush'. Depleting natural resources has meant that the recovery of gold continues to grow in importance and relevance.The Recovery of Gold from Secondary Sources analyses the most advanced technology in gold recovery and recycling from spent sources of mobile phones, unwanted electronic equipment and waste materials. State-of-the-art techniques of hydrometallurgical and bio-metallurgical processing, leaching, cementing, adsorbing and separation through bio-sorbents are all described in detail, providing a guide for students and researchers. Discussion of environmentally friendly methods of recovery are presented, in order to provide modern-day alternatives to previous techniques. For those interested in the study of gold recovery this book gives a comprehensive overview of current recovery, making it the ultimate source of information for students, researchers, chemists, metallurgists, environmental scientists and electronic waste recovery experts.
Book Synopsis A Process for the Recovery of Gold from Activated Carbon by Leaching and Electrolysis by : J. B. Zadra
Download or read book A Process for the Recovery of Gold from Activated Carbon by Leaching and Electrolysis written by J. B. Zadra and published by . This book was released on 1950 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Chemistry of Gold Extraction by : John Marsden
Download or read book The Chemistry of Gold Extraction written by John Marsden and published by SME. This book was released on 2006 with total page 688 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensively revised and updated, this edition provides the broad base of knowledge required by all working in the gold extraction and gold processing industries. It bridges the gap between research and industry by emphasizing practical applications of chemical principles and techniques.
Download or read book Gold written by Nathaniel Arbiter and published by CRC Press. This book was released on 1990 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The eight articles first appeared as volume 6 (no date) of Mineral processing and extractive metallurgy review. They review new methods of recovery for gold, and to some extent, silver, focus on the particular challenges of extraction from carbonaceous ores and from various sulfide-bearing ore, and the treatment of refractory gold ore, and discuss high-temperature and biological oxidation, high- temperature chlorination, and removing metals from leach liquor. Book club price, $40. Annotation copyrighted by Book News, Inc., Portland, OR
Book Synopsis Process Mineralogy IX by : W. Petruk
Download or read book Process Mineralogy IX written by W. Petruk and published by . This book was released on 1990 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Pyrometallurgical Recovery of Gold from Leach Residues by : Lawrence Bruce McRae
Download or read book The Pyrometallurgical Recovery of Gold from Leach Residues written by Lawrence Bruce McRae and published by . This book was released on 1992 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Unrestricted Mintek Publications by :
Download or read book Unrestricted Mintek Publications written by and published by . This book was released on 1987 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Gold Metallurgy and the Environment by : Sadia Ilyas
Download or read book Gold Metallurgy and the Environment written by Sadia Ilyas and published by CRC Press. This book was released on 2018-02-19 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives an overview of all the gold extraction processes along with their mechanistic study and environmental impact. Reviews extraction techniques previously employed as well as recently evolved technology for gold leaching, provides technical flow sheets for processing of ores with a diversity of lixiviants and offers a compulsory overview of every gold processing technique It also discusses recent integrated techniques including hydro- and bio-metallurgical techniques with examples
Book Synopsis The Recovery of Gold from Refractory Ores by :
Download or read book The Recovery of Gold from Refractory Ores written by and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Some recent work on the recovery of gold from refractory gold- bearing materials is described, special reference being made to some deposits in southern Africa. Possible explanations for the poor response of some gold-bearing materials to cyanidation are summarized, and the results of investigations into four techniques to enhance the response of refractory gold-bearing materials to cyanidation are presented. Mineralogical examinations of the feed and solid residues are used to show the reasons for the results obtained. Compared to conventional cyanide leaching, cyanidation under elevated pressure and lowered alkalinity significantly enhanced the rate of gold dissolution but, for all the samples except a stibnite concentrate, which gave a significantly better result, the final gold extraction showed no improvement. Activated carbon was deactivated, i.e. deprived of its ability to adsorb dissolved gold, by the addition of organic reagents. However, attempts similarly to poison the carbonaceous material in a sample of gold-bearing dump material were unsuccessful. Gold dissolution was enhanced by the oxidation of pyrite and arsenopyrite to sulphuric acid and aqueous ferric and arsenic species prior to cyanidation of the solid residue. A process comprising pyrolysis, mild oxidative leaching, the removal of elemental sulphur, and cyanidation gave gold dissolutions of up to 99 per cent, i.e. significantly better than by any other process.
Book Synopsis The Leaching of Base Metals from the Calcines Produced by the Roasting of Pyrite Concentrates by :
Download or read book The Leaching of Base Metals from the Calcines Produced by the Roasting of Pyrite Concentrates written by and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A number of gold and uranium plants in South Africa concentrate the pyrite in the ore or residue by flotation, and roast the concentrate for the production of sulphuric acid. The calcine produced, which is predominantly hematite, is generally subjected to cyanidation for the recovery of gold and silver that would normally not have been recovered in high yield from the primary concentrate. The calcines often contain economically significant quantities of copper, nickel, cobalt, and uranium. Prior treatment of the calcine for the recovery of these metals would be desirable in terms of the value of the products and also in terms of the possible increased gold recovery in the subsequent cyanidation of the leach residue. Several processes for the leaching of the base metals from plant calcines have been investigated, and an important general conclusion is that an adequate recovery of the base metals requires that a large proportion of the iron should also be extracted. This observation led to a more extensive investigation of the kinetics of the leaching of various iron oxides. The application of electrochemical theory and techniques resulted in a fuller understanding of the various factors that govern the rate of leaching of iron oxides. As a result of this fundamental work, alternative treatment schemes that should yield more efficient extraction from calcines were suggested. Several of these possibilities were investigated, and the most promising were found to require reducing conditions during the leach, or prior partial reduction of the calcine to magnetite or wustite. The effects of various process variables such as the type and concentration of the acid, the temperature, the residual sulphur in the calcine, and the source of the calcine were investigated. The effect of prior treatment of the calcine on subsequent gold recovery by cyanidation was also investigated for a number of the calcines.
Book Synopsis The Extractive Metallurgy of Gold by : John C. Yannopoulos
Download or read book The Extractive Metallurgy of Gold written by John C. Yannopoulos and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 285 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Investigation of Refractory Gold Ores. Suggestions for Future Work on Refractory Gold Ores of the Barberton Goldfield by :
Download or read book Investigation of Refractory Gold Ores. Suggestions for Future Work on Refractory Gold Ores of the Barberton Goldfield written by and published by . This book was released on 1966 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As a result of both the writer's visit to the Kalgoorlie goldfield in Western Australia and the testwork conducted in the Government Metallurgical Laboratory on refractory gold ores, several recommendations have been made in this report for future work on the refractory gold ores from the Barberton goldfield. The conclusion has been drawn that it is unlikely that a treatment method, for oxidation of auriferous sulphide concentrates, economically superior to roasting will be developed. Consequently, eight recommendations, oriented towards the possibility of increasing the income of the Barberton mines, have been made. These recommendations, which aim at reducing the gold content of all waste material discarded from the reduction works and developing the recovery of saleable material other than gold, are as follows: 1. That cyanidation of the flotation concentrate be investigated with special reference to reducing the gold value of the calcine cyanidation residue and to the recovery of silver. 2. That the method of roasting be assessed with a view to improving, if warranted, control over the chemical reactions involved during roasting. 3. That testwork be continued on the recovery of gold from the calcine cyanidation residue. 4. That methods for reducing the gold content of the flotation tailings be investigated. 5. That the recovery of arsenic and gold from the flue gases be investigated. 6. That the recovery of elemental sulphur, or alternatively, the manufacture of sulphuric acid be investigated. 7. That the recovery of gold from the carbonaceous scum from the Sheba mine be investigated. 8. That the pressure oxidation of the auriferous sulphide concentrate be investigated.
Book Synopsis Recovery of Gold from Arsenopyrite Concentrates by Cyanidation-carbon Adsorption by : Harold J. Heinen
Download or read book Recovery of Gold from Arsenopyrite Concentrates by Cyanidation-carbon Adsorption written by Harold J. Heinen and published by . This book was released on 1980 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Recovery of Pyrite and Gold from Acid-leach Residues from the Merriespruit Gold Mine by : PW. Overbeek
Download or read book The Recovery of Pyrite and Gold from Acid-leach Residues from the Merriespruit Gold Mine written by PW. Overbeek and published by . This book was released on 1982 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Batch flotation tests on acid-leach residue from Merriespruit Gold Mine showed that concentrate grades of up to 40 per cent sulphur can be readily obtained, although at low recoveries. Flotation tests at the pilot plant gave better results than did the batch tests. The initial results showed that 76 per cent of the sulphur content of the feed can be recovered in a concentrate that assays 47,0 per cent sulphur. Attempts to improve the recovery at the expense of the grade were not successful, the highest recovery obtained being 79,7 per cent at a concentrate grade of 36,8 per cent sulphur. The gold recovery at that stage was 47,2 per cent. A gradual deterioration in flotation response was noted as the tests progressed, and this was attributed to possible deterioration of the feed material due to oxidation. However, this was not proved conclusively. It was concluded that, by use of the flotation conditions recommended by the sponsor, the required grade of 38 per cent sulphur could be readily obtained at recoveries of more than 75 per cent of the sulphur present in the feed material. In a second phase of the project, cyanidation tests were carried out on roasted and unroasted flotation concentrates produced in the pilot plant. The average gold extraction for the roasted material was 68 per cent. Additions of lime were found to be important, and an excess of lime resulted in lower gold extractions. The extraction of gold from unroasted material was not as successful as from the roasted material. The maximum recovery from unroasted material after fine grinding was 63 per cent. The consumption of lime was high in all these tests, and 22 kg of lime per ton of concentrate was used for the test in which the maximum gold extraction was obtained. Finally, settling tests were carried out on tailings so that the settling characteristics in an acid medium could be established. It was found that, in the pH range 3,5 to 4,5, the settling rate was two to three times lower than it had been as a pH range 3,5 to 4,5, the settling rate was two to three times lower than it had been at a pH value of 11,0.
