Reverberatory Furnace for the Carinthian Process English Reverberatory Furnace in use in Flintshire. 29, 30 Vogl's Cupola Furnace. 101-104 101-104 45-49 Furnaces which are a combination of Reverberatory and Muffle Furnaces used at Freiberg for Roasting Ores Wellner's Double Cupola Furnace used in Freiberg . 193, 194 64, 65 Cupola (Sump) Furnace used for Raw Smelting 69-72 Apparatus for Pattinson's Process 81-85 English Cupelling Furnace used at Stolberg (Prussia) 94 95 96 97 98 99 100, 101 Amalgamation Machinery used in Freiberg Stamps for Crushing Ores (Molinos) in Mexico Apparatus for the Extraction of Silver used in Freiberg 102-105 Double Roasting Furnace used at Mansfeld 106 107, 108 109-113 114, 115 116 117, 118 Apparatus for Extracting Silver with Warm Water ZINC. Cupola Furnace having a Fire-grate used in Spain for Double Muffle Furnace for Calcination used in Przibram 417-419 410, 411 Retort and Adapters used on the Continent 431 Furnace for Burning Muffles used at Llansamlet, near 432 125-129 Belgian-Silesian Distillation Furnace 440 Adapter used at Valentin Cocq 441 449 Muffle and Adapter used at Borbeck 449 449 130 131, 132 Muffle Furnace with Two Rows of Muffles one above the 450 452 133, 134 Pots for Re-melting Zinc used at Llansamlet near 456 135, 136 Reverberatory Furnace for Re-melting Zinc used in 460 Silesia 462 TIN. 137, 138 139 Roasting Furnaces with Condensers, as used in Saxony 140, 141 142 143, 144 Tin Smelting Furnace at Truro, in Cornwall. Apparatus for Liquating Antimony used at Wolfsberg Distilling the Amalgam 180 181 182 183, 184 185 186 187-189 190, 191 Section in the Clunes Gold Mining Field (Australia) . Gold Mills, used at Schemnitz. Apparatus for Pressing the Auriferous Mercury 615 616 616 632 633 634 Extracting Gold used at Reichenstein 639, 640 Extracting Gold used at Schemnitz 644 Refining Gold used at the Lower Hartz 667 Pressing the Silver used at the Lower Hartz 668,669 PLATINUM. A PRACTICAL TREATISE ON METALLURGY. CHAPTER I. LEAD. PRINCIPAL ORES OF LEAD. IN these ores the lead is contained in the form of sulphide or oxide. The principal ores are the following: 1. Galena (sulphide of lead), PbS, containing 86.57 per cent Pb, and 13°43 per cent S. It usually contains sulphide of silver in an isomorphous state. The amount of silver varies, in most cases, between o'oï and o‘30 per cent, sometimes rising to o'50, or even I per cent. In the latter case, however, silver does not occur as isomorphous sulphide of silver, but as silver ore disseminated through the galena. Upon treating galena by reagents, it may frequently.be ascertained in what state of combination the silver exists in the ore. Malaguti and Durocher* found silver in galena, from mere traces up to more than 7 per cent. The amount of silver varies not only in different deposits of the same locality, but sometimes even in the same bed, and is found to bear no relation whatever to the structure of the ore. * MALAGUTI and DUROCHER, in Annales des Mines, 4 ser., tom. xvii., 1805; FABRE, in Bulletin de la Société de l'Industrie Minérale, tom. iii., p. 281, 1857-1858. Berg. u. hüttenm. Ztg., 1859, p. 446, 447. B It appears that the period of the formation of the ore has had an essential influence upon the amount of silver contained in it; galena in veins usually possesses a greater amount than galena in beds, or when diffused through other ores. Moreover, the purest galena contains the least silver. The prevailing opinion that lamellar galena contains more silver than granular galena, and that in the latter the silver occurs as mechanically included sulphide, is not always correct. Ores containing a small amount of lead, sometimes owe their entire value to the other metals, silver, gold, and copper, which they accidentally contain. Galena is found in almost all countries, and in nearly all geological formations.* It occurs : A. In CRYSTALLINE SLATES and UNSTRATIFIED ROCKS. a. In veins. In gneiss (Black Forest, Odenwald, Saxon Erzgebirge, Oberpfalz, Silesian Sudeten, Riesengebirge, Bleistadt in Bohemia, Central France, Kongsberg); in mica schist (Bleistadt in Bohemia, Spain, Kongsberg, Sardinia, Tuscany); in granite (Badenweiler, Sohneeberg, Linares in Spain, Wicklow in Ireland, Central France); in quartz slate (Kongsberg); in granular limestone (Schwarzenberg in Erzgebirge); in magnesian slate (Sardinia); in porphyry (Central France, i.e., Pontgibaud); in trachytic porphyry (Felsobanya, Kapnik); in greenstone (Schemnitz); in greywacke, quartz, and greenstone (Przibram). b. In beds. In mica schist (Tuscany, Fahlun). c. In floors. In mica schist and granular limestone (Ruszkitza in Banat); in mica schist, granular limestone, and syenite (Dognaska, in Banat); in granite (Christiania); in syenite (Christiania); in mica schist (Tuscany). d. Impregnated, in granular limestone (Sala). B. In CAMBRIAN CLAY SLATE. &c., in Wales). C. In SILURIAN SLATES. In veins (Cardiganshire, a. In veins. In clay slate (Harzgerode on the Hartz, Mies in Bohemia, Carthagena in Spain). Ann. d. Min., 4 ser., xvii., 83. Ueber das Vorkommen der Bleierze, see v. DECHEN, Statistik des nördl, and zollv. Deutschland, i., 750. COTTA, Lehre von den Erzlagerstätten, 1860, ii., 570 and 618. |