Manual of Determinative Mineralogy; With an Introduction on Blowpipe Analysis

Manual of Determinative Mineralogy; With an Introduction on Blowpipe Analysis

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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: ...and fused before the blowpipe, first in the reducing flame until a bright metallic surface is obtained, and then in a small oxidizing flame (Fig. 41). It is necessary to heat in the oxidizing flame for several minutes in order to oxidize the lead, during which time the surface of the button shows a play of rainbow colors, due to a thin film of lead oxide, which constantly flows to the sides, and is absorbed by the bone-ash. Finally, when the last of the lead is oxidized, the play of color ceases, the globule is said to " blick," and the operation is completed. Frequently the amount of lead oxide formed is so great that it cannot all be absorbed by one cupel. The button then becomes surrounded by, and seems to float upon, the fused lead oxide, and when this happens, it is best to interrupt the operation and oxidize the last of the lead upon a fresh cupel. C onsiderable practice is needed in order to 'make the silver assay easily and quickly, but when the necessary skill has been acquired, the operation may be performed in less than fifteen minutes, and by assaying samples of known value and saving the silver beads for comparison, one can soon learn to judge of the relative values of ores. By starting with weighed quantitiea of material, and especially by making use of the special apparatus mentioned in Plattner's elaborate treatise, very good quantitative determinations of silver may be made by means of the blowpipe assay. 3. Precipitation as Silver Chloride.--Silver chloride, AgCl, is very insoluble in water and dilute nitric acid. A white precipitate of silver chloride will therefore form if silver is dissolved in dilute nitric acid (1HNO: 211,0) and a few drops of hydrochloric acid are added to the solution. If the more

Product details

  • Paperback | 88 pages
  • 188.98 x 246.13 x 4.57mm | 176.9g
  • United States
  • English
  • black & white illustrations
  • 1236887824
  • 9781236887825