The Mining and Metallurgy of Gold and Silver

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E. and F.N. Spon, 1867 - Gold - 532 pages
 

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Page 120 - Statistical Abstract for the several Colonial and other Possessions of the United Kingdom in each year, from 1852 to 1865.
Page 507 - The proportion of oxide of lead to bo added to ores of this description varies in accordance with their composition, but it should in all cases be present in decided excess, since, should the sulphides not become completely decomposed, the whole of the silver will not be concentrated in the resulting button of alloy. For the successful assay of pure argentiferous iron pyrites, as many as 50 parts of litharge are required, whilst for mispickel, blende, copper, pyrites, grey cobalt, and sulphide of...
Page 178 - ... towards the stampers. When these are not employed, spaces for the accumulation of amalgam are allowed between the dies and the sides of the box, and vertical iron bars are placed inside the gratings, between which the hard amalgam is found to collect. The copper plates are covered with mercury, by means of a rag dipped in dilute nitric acid, with which quicksilver is rubbed over the surfaces to be coated, in the same way as on these used in ordinary sluices.
Page 506 - ... oxidizing their constituents, with the exception of the precious metals, which form an alloy with the lead set free. The slags resulting from this operation contain the excess of litharge added, and the button of alloy produced is subjected to cupellation. The proportion of oxide of lead to...
Page 250 - A lurge amount of silver is likewise extracted from galena, with which it is associated in the form of sulphide. Few metals enter into a greater variety of natural combinations, or are found over a wider geological range, than silver. It is said to exist in minute traces in some organic bodies, and in the waters of the ocean.
Page 296 - O'Reilly and Patrick McLaughlin, while engaged in gold-washing in what is now the ground of the Ophir Mining Company, and near the south line of the Mexican Company's claim, discovered a rich vein of sulphuret of silver in an excavation made for the purpose of collecting water to use in their rockers in washing the gold.
Page 224 - There are still other metals which will usually be found adherent to the amalgam when sodium has been used ; such as platinum and osmiridium. These, like iron, immediately detach themselves on the removal of the sodium by boiling the diluted amalgam in water. A mixture of platinum or osmiridium, or both, with iron, may of course be freed from the latter by the magnet It will generally be found desirable, as in other cases where quicksilver is used and ores containing arsenic or sulphur operated upon,...
Page 454 - By this treatment the antimony, copper, and other impurities become oxidized, and, rising to the surface, are skimmed off, and removed by means of an iron rake. The length of time necessary for the purification of hard lead obviously depends on the nature and amount of the impurities with which it is associated ; and consequently some varieties will be sufficiently softened at the expiration of twelve hours, whilst in other instances it becomes necessary to continue the operation during several days....
Page 222 - ... of a sluice, and in all forms of amalgamators through which a continual current of fresh water is kept running; mercurial solutions of sodium, as I have discovered, being little affected by water which is free from acid, alkaline, or saline impurities. In those cases, however, in which little water is employed, and especially where the ore and quicksilver are ground up together into...
Page 507 - ... present, not always excepting silver itself. When, however, the mixture at the same time contains an excess of litharge, and nitre has not been added in sufficient quantity to effect the decomposition of the whole of the sulphides present, reaction takes place between the portion of sulphide undecomposed and the oxide of lead added. This gives rise to the formation of a button of metallic lead, which, combining with the silver, affords a button of alloy suitable for cupellation. The amount of...

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