Chambers's encyclopaedia; a dictionary of universal knowledge . useat some silver-extraction works in America. TheFreil)erg ores are complex. Certain lodes containvarious sulphuretted silver ores in quartz vein-stufi,but other lodes yield along with these argentiferousgalena, zinc-blende, copjier and iron jnrites, andother metalliferous minerals in a vein-stufi ofbaryta, spathic carbonates, &c. These ores werepulveriseil and so mixed that the poorer class con-tained 30 or 40 ounces of silver per ton, and thericher three or fimr times as much. An ore ofthis nature is with common
Chambers's encyclopaedia; a dictionary of universal knowledge . useat some silver-extraction works in America. TheFreil)erg ores are complex. Certain lodes containvarious sulphuretted silver ores in quartz vein-stufi,but other lodes yield along with these argentiferousgalena, zinc-blende, copjier and iron jnrites, andother metalliferous minerals in a vein-stufi ofbaryta, spathic carbonates, &c. These ores werepulveriseil and so mixed that the poorer class con-tained 30 or 40 ounces of silver per ton, and thericher three or fimr times as much. An ore ofthis nature is with common salt to convertthe sulphide of silver into chloride, after which itis tinely grouml and place<l in the amalgamatingcasks along with water, scrap-iron, and iron reduces the bUver to the metallic state, and it then combines with the mercury to form anamalgam which, when sejiarated from the resi-dues, is distilled in iron retorts. This is a moreperfect .system than the Mexican method, but thereIS a considerable expense for fuel. Fig. 2 shows. Fig. 2.—Vertical Section of Amalgamating Apparatus: C, C, oak Kirrels; S, toothed wheel for settint: the barrels in motion; A, A, troughs for amalgam; T,T, troughs for residues. the arrangement of rotating barrels used in thisprocess. At the present time silver is obtained at theFreiberg works by the smelting of argentiferouslead and coi)per ores in a Iilz blast-fninace, anillustration, ot which is given in the article Le.\ charge is composed of lead ores, zinc-blende,and pyritic ores, some of which are highly ore-mixture contains the following metals,the average percentage of each being—lead 23,zinc 1.}, copper 3, and silver -OS to 60, together withsulphur and quartz gangue. The ore is lirst roastedin a reverberatory furnace, and theu smelted in thePilz furnace along with slags and varioiLs residuesrich in .silver. Coke is used as fuel, and the pro-ducts of the furnace are lead containing a variableamo
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