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Author: H. W. Mcculloch
Publisher:
ISBN:
Category : Gold
Languages : en
Pages : 70
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Book Description
Author: H. W. Mcculloch
Publisher:
ISBN:
Category : Gold
Languages : en
Pages : 70
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Book Description
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.
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Category :
Languages : en
Pages :
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The construction and the operation of the kiln is described. The effect of the temperature and the residence time in the kiln on the subsequent gold recovery, and on the arsenic, sulphur, and carbon contents of the product, have been investigated. Activation of the carbon, by roasting, yields low gold-extraction figures, owing to the precipitation of the gold onto the carbon. At high temperatures (ie, 730 degrees C), where the carbon is substantially burnt off, the gold extraction increases to a value of 74.5 per cent. The alloying or coating of the gold by lead compounds or other constituents in the ore during roasting is thought to be the cause of the limit to the maximum gold extraction figures obtained. Arsenic does not appear to have any effect on the extraction of gold from the ore. The pyrite surrounding the gold particles is decomposed and cracked during roasting, thus allowing penetration by the cyanide solution.
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Category :
Languages : en
Pages : 19
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Additional samples of ore from the Giant Reefs Mine were investigated in the light of previously reported results. Fine grinding and dilute leaching in the presence, and in the absence, of mill waters was carried out. It was found that the refractoriness of these ores is due to the chemical interference during cyanidation and that satisfactory results could be obtained by leaching at 5:1 liquid/solid ratio in the presence of mill water. As the mine was not in operation when samples were taken, no sample representing a 'mill head' could be obtained. Therefore each of the samples investigated was composed of rock chippings from one particular site. These samples differed from each other considerably in grade and composition. It was found impossible to assign a constant head value and behaviour to any of the samples because significant variations in gold content and chemical activity were observed in duplicate portions of each of the samples. This variability of properties made it impossible to determine exact conditions for maximum gold extraction for any of the samples. However, the above-mentioned leaching technique was found to give consistently high extractions on duplicate portions of each of the samples.
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Category :
Languages : en
Pages : 15
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A mineralogical investigation of the main causes of refractoriness of metallurgically complex gold ores in South Africa is reported. It is suggested that this refractoriness is related to the presence of submicroscopic gold, carbonaceous material, pyrrhotite, and base-metal sulphides. Means by which problems in the beneficiation of these ores can be overcome were also investigated, and some possible solutions to these problems are offered. A study of beneficiation products from the Fairview Mine showed that submicroscopic gold is associated mainly with arsenopyrite, the gold content of which can be up to 2700 g/t. During miling of the ore, the grains of arsenopyrite, which are smaller than 150 um and have a low resistance to attrition, are selectively broken down. The response of the ultrafine sulphide particles to flotation is relatively poor, and they are preferentially lost to the final tailings together with the gold they contain. It is suggested that the overgrinding of auriferous sulphides can be minimized by the removal of the coarse sulphides from the comminution circuit by flotation or gravity separation. At high rates of aeration in the scavenger and cleaner flotation cells, ultrafine gangue and pyrrhotite are selectively recovered. This material may be recirculated and build up in the flotation circuit, where it may have a detrimental effect on the flotation of the sulphides. Hence, if the amounts of these components can be minimized, the recovery of the gold and the sulphides in these refractory ores can be improved. Means by which this might be accomplished are suggested.
Author: Peter Michael Swash
Publisher:
ISBN: 9780869997840
Category : Gold
Languages : en
Pages : 15
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Category :
Languages : en
Pages :
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This report discusses the visit paid to the Barberton Goldfields over the period 27th-30th May 1964. The following recommendations, arising out of the visit, are made: (i) the question of metallurgical balances should be raised with the mining companies, (ii) work should be carried out, using the hot-stage microscope technique, to investigate the chemistry of the roasting process.
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Languages : en
Pages :
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Book Description
Ore from the Golden Hill Mine is a refractory ore in that less than 8 per cent of the gold can be extracted by conventional cyanidation. Mineralogical examination has shown that over 99 per cent of the gold is included in the sulphide minerals, in particular in the pyrite. The average particle size of the gold is small, being 7 by 5 microns. Chemical tests have shown that there are two causes for the refractoriness of this ore: (1) Lock-up of the gold in the sulphidic minerals. (2) Precipitation of the gold from solution by the carbon present (0.6 per cent) in the ore. Good extractions (96 per cent) of the gold could be obtained only after roasting a sulphide concentrate of this ore before cyanidation. This is the only method of treating this ore that has been effective to date. The conditions and results of all tests conducted on this ore are given in an appendix.
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Languages : en
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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.
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ISBN:
Category :
Languages : en
Pages : 11
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This report covers an investigation into the manner of occurrence of gold in an old mine dump of calcined tailings at the Fairview Mine. Previous investigations had not revealed the whereabouts of the gold still present in this dump, which amounts to between 10 and 12 ppm. In the present investigation, in which heavy-liquid separation was combined with X-ray, microscope, and electron-microprobe investigations, it was found that a significant proportion of the gold is adsorbed on carbon, and that a smaller proportion is present in pyrite that escaped complete calcination. An enigma is the occurrence of ferrosilicon, some of which contains gold. Although this study produced new information, a more detailed quantitative investigation is required in which an image analyser should be used to provide reliable quantitative data.
