Metallurgy of Gold, Silver, Copper, Lead, and Zinc Volume 2

Metallurgy of Gold, Silver, Copper, Lead, and Zinc Volume 2

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1902 edition. Excerpt: ...time stir it thoroughly; the steam pressure is so adjusted, it will be unable to overcome the increased resistance, two-thirds of the contents of the kettle having become crystallized. The hood is then removed, the outlet at the bottom opened, and the liquid lead allowed to drain from the crystals, which are retained by the strainer. The liquid lead is transferred to one of the auxiliary melting pots, and the cystals may be charged at once into the second for fusion with a further amount of base bullion of the same tenor, i. e., silver contents, or set aside for treatment at some more convenient time. The operation is then repeated and base bullion of all values is thus separated in the one crystallizing kettle, care being taken, of course, ' to avoid confusion of lots of different values. The operation is accomplished much more quickly by steam than by hand, and the size of a plant with an equal output is much smaller than in the case of the old method. 8O. The Parkes Process.--The Pattinson method was a very decided-step in the direction of reducing the amount of lead to be cupeled by concentrating the silver in a comparatively small portion of it, but this has been greatly improved upon by the Parkes process. The fundamental principles on which the Parkes process rests are these: If molten zinc is mixed with molten base bullion, the silver has a greater aflinity for the zinc than for the lead, and the result is the formation of a zinc-silver alloy, which is less fusible than the base bullion, very slightly soluble in molten lead, and even less so in lead saturated with zinc. This alloy will separate, therefore, from the molten lead, and, being lighter, will float to the surface in what is known as a crust; in this form it may be...
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Product details

  • Paperback | 148 pages
  • 189 x 246 x 8mm | 277g
  • United States
  • English
  • black & white illustrations
  • 1236909917
  • 9781236909916