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acid alumina amount antimony assay assume atom base side behavior blast furnace brick burn calculations Calories carbon chalcopyrite charge chemical coke coke-ash combine combustion composition concentration considerable consists constituents converter copper smelting Cu2S cuprous oxide cuprous sulphide determine excess ferrous oxide ferrous silicate ferrous sulphide FeS2 flue-dust flux form a bisilicate formation formation-temperature fuel fusible fusion gases gold hearth heat hematite impurities increased iron oxide iron sulphide lime limestone liquid loss Lyell magnesia material matte contains melt metallic copper metallurgical metallurgist method mixture operation ordinary oxygen particles percentage portion pound practice precious metals present proportion pyrite furnace pyrite smelting pyrrhotite quantity quartz reactions reducing refining result reverberatory furnace shaft silica silver singulosilicate SiOj slag slag containing slag-forming smelter substances sufficient suitable sulphate sulphur dioxide surface temperature tion tons tuyeres unit weight white metal zinc
Page 333 - As may be imagined, the main endeavor of the metallurgist in this typo of smelting is to keep the proportion of coke to ore as low as possible; not merely because coke costs money, but still more because any excess of coke causes a lowering in the grade of the matte, due to its interference with the oxidation of the sulphides. A furnace in proper condition, and running on a suitable charge, is extraordinarily sensitive on this point. The increase of the coke from a standard charge of 60 Ib.
Page 333 - the amount of coke present carries the melting process high up above the proper zone of oxidation, and to regions where there is yet no formation of FeO. Half-fused masses of acid, earthy silicates are formed, and much — in some cases, all — of the free silica is combined with the alumina, lime, magnesia, manganese, alkalies, and already oxidized iron, all of which substances are likely to be present in the ore mixture. It is not that the affinity of the silica is satisfied in forming these preliminary,...
Page 109 - ... present, stand little chance of obtaining any of the oxygen to combine with, to form sulphur dioxide and metal oxide. The atmosphere is almost always strongly reducing, and the sulphides tend to melt down with almost the same result that they would in a closed crucible, with complete exclusion of air. ... It will thus be seen that, owing to the reducing atmosphere which prevails, we can, when smelting sulphide ores, look for the removal of but little sulphur in the blast furnace beyond the portion...
Page 521 - Proceedings of the Subscribers to the Fund for Obviating the Inconvenience Arising from the Smoke Produced by Smelting Copper Ores...
Page 173 - ... affected by the mutual action of the various constituents of the charge itself. This renders the chemical part of the operation unusually simple, and enables the smelter to concentrate his efforts upon developing the high temperature essential to the complete fusion of the ore.
Page 173 - ... smelting of roasted ores, and the pyrite smelting of sulphide ores; namely, carbon in the one case, and oxygen in the other. . . . Speaking in a broad general sense, the ore in the reverberatory smelting furnace is subjected to neither of these influences to any marked degree, and is thus enabled to work out its own salvation under the influence of heat alone. Such chemical reactions as take place in the ore mass during the smelting result almost entirely from the behavior of substances already...
Page 214 - ... process is obtained in this manner, we have what is known as pyrite smelting. If only a part, semi-pyrite smelting. However, Peters states that so far as he is aware, in all pyrite furnaces of the world, a small amount of fuel (usually coke) is added to the charge, and " this amount may vary anywhere from 0.5 per cent, of the weight of the charge up to a proportion that might be actually enough to melt the ore without any heat at all being derived from the sulphides.
Page 109 - Therefore, in ordinary blast furnace smelting with carbonaceous fuel, the sulphides of iron and copper, and such small quantities of other metallic sulphides as may be present, stand little chance of obtaining any of the oxygen to combine with, to form sulphur dioxide and metal oxide. The atmosphere is almost always strongly reducing, and the sulphides tend to melt down with almost the same result that they would in a closed crucible, with complete exclusion of air.
Page 170 - ... as copper ores are smelted in one of two ways, that is, either in a reverberatory or in a blast furnace, it will first be necessary to ascertain if the conditions essential for the successful carrying out of these two methods of smelting can be attained in the electric furnace. As stated by Peters,1 "the one fundamental and pre-eminent duty of this type of furnace is to produce a smelting temperature so that the ore may become liquid, and thus be able to separate into slag and matte.
Page 109 - when fused in a reducing atmosphere, certain of the sulphides, such as Cu2S, FeS, PbS, etc., melt down without change, while the very common and important mineral, pyrite, loses about one-half of its sulphur, which is driven off as sulphur, in the shape of yellowish fumes, which will deposit a coating of brimstone on a cool surface.