Gold and Other Precious Metals

A view of gold and other precious metal extractions from a new and wider angle, taking in both the earth and the metallurgical sciences. To name but a small number of the topics covered: - Occurrences of gold and silver minerals in their ores - Photomicrographs of refractory and amenable minerals/ores - The use of irregular gold and silver distributions for efficient planning of the extraction process - Microanalytical techniques - Descriptions of uranium and many base metals for comparison. Written with a broad audience in mind, from the manager of operations to the metallurgist, for the field geologist or other earth scientist, and for the professor and student alike.

Contenu

I.- 1 The mineral industry - Present state of the art.- 2 Reasons for poor planning of precious metal recoveries.- 3 Market value and other variables affecting recovery decisions and recovery costs.- Metal geochemistry.- Ore chemistry.- Rock types - Physical character of host rock.- Mineralogy/ore microcomposition.- Metal-bearing minerals.- Chemical composition of the metal-bearing mineral.- Grain size of the metal-bearing mineral.- Host minerals and mineral associations.- Minerals other than the host mineral.- Mineral stability.- 4 Methods and techniques for the study of ores.- The microanalytical techniques.- The ore microscope.- The electron microprobe.- The scanning electron microscope (SEM).- Choice and preparation of samples.- Incorrect approach.- Basic steps for the study of metal distributions.- Misconception.- Applications.- Use of the microprobe preferable to that of the EDS-SEM.- Use of the EDS-SEM preferable to that of the microprobe.- 5 General principles of mineral processing.- Comminution.- Physical separation.- Hand sorting.- Gravity concentration.- Magnetic separation.- Flotation.- Other techniques.- Ores to which little beneficiation is applied.- Sintering and pelletizing.- Roasting.- Oxidation.- Chlorination.- Reduction.- Sulfation and sulfidation.- Chemical separation.- Leaching.- Solid-liquid separation.- Solution purification and concentration.- Smelting.- Casting.- Recovery from solutions - Refining.- Precipitation.- Electrolysis.- Evaporation and crystallization.- Refining.- II.- 6 Gold.- Market value.- Geochemistry.- Fire assay.- Rock types hosting gold.- Ore microcomposition.- Gold-bearing minerals.- Native gold and electrum.- The other gold-bearing minerals.- Grain size.- Host minerals.- Pyrite.- Arsenopyrite.- Realgar and orpiment.- Chalcopyrite.- Secondary copper minerals.- Other sulfides and sulfosalts.- Oxides of iron.- Uranium minerals.- Quartz, silicates, carbonates and sulfates.- Carbonaceous material (graphite/carbon).- Sands and gravels (placer gold).- Mineral associations.- Minerals other than the host mineral.- Mineral stability.- Method of study.- Metallurgy.- Rock types hosting gold.- Gold-bearing minerals.- Native gold and low-silver electrum.- High-silver electrum.- Tellurides.- Other gold-bearing minerals.- Grain size and mineral associations.- Host minerals.- Pyrite.- Arsenopyrite.- Realgar and orpiment.- Chalcopyrite and secondary copper minerals.- Pyrrhotite.- Marcasite.- Galena and other lead minerals.- Sphalerite.- Stibnite and antimony sulfosalts.- Other sulfides and sulfosalts.- Oxides of iron (and other oxidized minerals).- Uranium minerals.- Quarts, silicates, carbonates and sulfates.- Carbonaceous material.- Sands and gravels (placer gold).- Minerals other than the host mineral.- Cyanicides.- Clay and sericite.- Carbonaceous material (graphite and carbon).- Mercury minerals.- Discussion and conclusions.- 7 Silver.- Market value.- Geochemistry.- Rock types hosting silver.- Ore microcomposition.- Silver-bearing minerals.- Native silver.- Electrum and kustelite.- Acanthite - Argentite.- Pyrargyrite - Proustite.- Tetrahedrite - Tennantite.- Polybasite, perceite and stephanite.- Stromeyerite.- Cerargyrite and the other silver halides.- Argentojarosite and argentian plumbojarosite.- Manganese minerals.- Other minerals in which silver is a minor constituent.- Grain size.- Host minerals.- Mineral associations.- Mineral stability.- Method of study.- Metallurgy.- Rock types hosting silver.- Silver-bearing minerals.- Native silver, electrum, acanthite, cerargyrite and secondary copper minerals.- Tetrahedrite - Tennantite.- Manganese minerals.- Other silver minerals.- Grain size and host minerals.- Minerals other than the host mineral.- Mineral stability.- Discussion and conclusions.- 8 Differences between gold and silver and their effects on recoveries.- 9 Platinum group elements.- Ruthenium.- Rhodium.- Palladium.- Osmium.- Iridium.- Platinum.- Market value.- Geochemistry.- Rock types hosting the platinum group elements.- Ore microcomposition.- Method of study.- Metallurgy.- 10 Uranium.- Market value.- Geochemistry.- Rock types hosting uranium.- Ore microcomposition.- Uranium-bearing minerals.- Uraninite-pitchblende.- Secondary products after uraninite-pitchblende.- Coffinite.- Complex multiple oxides.- Uranothorite.- Thucholite.- Miscellaneous accessory minerals.- Grain size, host minerals and mineral associations.- Minerals other than the host mineral.- Mineral stability.- Method of study.- Metallurgy.- The primary uranium minerals.- The secondary products.- The complex multiple oxides.- 11 Base metals.- Method of study.- Beryllium.- Mineralogy.- Metallurgy.- Boron.- Mineralogy.- Metallurgy.- Carbon.- Mineralogy.- Metallurgy.- Magnesium.- Mineralogy.- Metallurgy.- Aluminum.- Mineralogy.- Metallurgy.- Potassium.- Mineralogy.- Metallurgy.- Titanium.- Mineralogy.- Metallurgy.- Chromium.- Mineralogy.- Metallurgy.- Manganese.- Mineralogy.- Metallurgy.- Iron.- Mineralogy.- Metallurgy.- Cobalt.- Mineralogy.- Metallurgy.- Nickel.- Mineralogy.- Metallurgy.- Copper.- Mineralogy.- Metallurgy.- Lead and zinc.- Mineralogy.- Metallurgy.- Arsenic.- Mineralogy.- Metallurgy.- Niobium and tantalum.- Mineralogy.- Metallurgy.- Molybdenum.- Mineralogy.- Metallurgy.- Tin.- Mineralogy.- Metallurgy.- Antimony.- Mineralogy.- Metallurgy.- Barium.- Mineralogy.- Metallurgy.- Rare earths.- Mineralogy.- Metallurgy.- Tungsten.- Mineralogy.- Metallurgy.- Mercury.- Mineralogy.- Metallurgy.- Bismuth.- Mineralogy.- Metallurgy.- Recent Diamond Discoveries.- 12 Mineral exploration.- Determination of the origin of a mineralization.- Evaluation of a deposit.- Conclusions.- Glossary of Minerals, Rocks and Geological Terms.- References.