A Manual of MetallurgyEllis & White, 1873 - 592 Seiten |
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added alkaline alloy amalgam ammonia amount antimony apparatus aqua regia argentic chloride arsenic assay atomic weight bismuth blast blowpipe boiling borax brittle carried cent charcoal chloric acid clay coal colour combines combustion compound condensing containing cooling copper crucible crystalline crystals cupel cupric decomposed dihydric sulphide dilute dissolved distilled employed excess ferric ferrous filtered flame flux formed fuel furnace fused fusible fusion gold grains heat hence hydrated hydrochloric acid hydrogen inches insoluble iridium iron Lastly latter lead litharge malleable mass melting mercury metal mixed mixture muffle nickel nitrate nitric acid obtained operation ordinary oxide oxygen passing placed plate platinum plumbic portion potassic powder precipitate produced proportion pure quartz readily reduced remaining removed roasting salt separated sesquioxide silica silver slag small quantity sodic chloride soluble solution specific gravity steel sulphate sulphuric acid surface temperature thrown tion tube vessel washed wire zinc
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Seite 392 - ... •weight. Then, by estimating the sulphur, the difference between its weight and that of the whole precipitate gives that of the antimony. We may operate thus: — To the hydrochloric solution add a little tartaric acid, and then pass in H S. Thus the sulphide is thrown down. Wash, dry, and weigh this. Next dissolve it in aqua regia; then mix this with a solution of tartaric acid, and precipitate the sulphuric acid (formed by the oxidation of the sulphur of the sulphide) by means of chloride...
Seite 144 - The chloride, or corrosive sublimate, is prepared in the same way, but with the omission of the second quantity of mercury ; hence, in subliming, it is a mixture of common salt, with sulphate of the red oxide which is operated upon. It may also be made by dissolving the red or yellow oxide in hot hydrochloric acid, when crystals of corrosive sublimate separate on cooling in transparent four-sided prisms, which are colourless, and soluble in 1 6 parts of cold, or in 3 parts of boiling water : and...
Seite 293 - Those who would view this subject scientifically should here consider, that as platina cannot be fused by the utmost heat of our furnaces, and consequently cannot be freed like other metals, from its impurities, during igneous fusion, by fluxes, nor be rendered homogeneous by liquefaction, the mechanical diffusion through water should here be made to answer, as far as may be...
Seite 549 - ... between the plates is made, the needle will be deflected from its natural position as regards the north — an indication that a current of electricity is traversing the wire, and which current experiment has shown to be generated in the liquid at the zinc surface, and, passing thence through the fluid to the platinum, returns by the connecting wire to the zinc; and further, the deflection of the needle to the right or to the left indicates most certainly which end of the wire is connected with...
Seite 126 - F., it suffices to make the lower protecting tube also of wrought-iron, to save expense. This lower portion only, up to the conical enlargement or boss of iron, is exposed to the heat to be measured. Three leading wires of insulated copper united into a light cable connect the pyrometer with the measuring instrument, which may be at a distance of some hundred yards from the same. They are connected by means of...
Seite 293 - ... heavy hammer, so as at one heating effectually to close the metal. If in this process of forging, the cylinder should become bent, it should on no account be hammered on the side, by which treatment it would be cracked irremediably; but must be straightened by blows upon the extremities, dexterously directed, so as to reduce to a straight line the parts which project. The work of the operator is now so far complete, that the ingot of platina may be reduced, by the processes of heating and forging,...
Seite 244 - ... being formed, which is then sold as " blue liquor." The use of sulphuric acid for the operation is preferred at many refineries, particularly on the Continent. It is more economical, for not only is the acid itself much cheaper, but the resulting gold is more thoroughly freed from silver; indeed, it is said that gold which has been refined by nitric acid may subsequently have more silver separated from it by the sulphuric acid process. In operating the metals are so mixed as that the gold amounts,...
Seite 67 - Pillichody f remarks as follows: When the points of solidification are observed by immersing the thermometer in the melted alloy, it usually exhibits, during the passage of the mass from the liquid to the solid state, two stationary points. This effect is due to the separation of one or other of the component metals, while an alloy of constant composition still remains liquid. This alloy corresponds to the composition Sn3 Pb.
Seite 294 - By repeated washing, shaking, and decanting, the finer parts of the gray powder of platina may be obtained as pure* as other metals are rendered by the various processes of ordinary metallurgy; and if now poured over, and allowed to subside in a clean basin, a uniform mud or pulp will be obtained, ready for the further process of casting.