This spark speeds location of high-grade ore
A l u m i n u m C o m p a n y of America uses direct-reading spectroscopy to help e v a l u a t e high-grade bauxite deposits. Before Alcoa begins surface mining operations, exploration teams m a k e preliminary chemical ore analyses in field labs. Samples that show up well go by air to Alcoa's Research Laboratories at New Kensington, P a . Samples are fused, pulverized, mixed with powdered graphite and cold-pressed into pellets for spectral analysis. Results—obtained quickly and economically by direct reading spectroscopy—are combined with other analytical data and plotted on maps of the mining area. An important aid in guiding bauxite exploration, spec-
tro-analysis helps reduce "guesswork" in locating ore concentrations. H o w N A T I O N A L G r a p h i t e plays a n important part in ore analysis. " N a t i o n a l " powdered graphite is mixed with each ore sample so it may function as a spectrometer electrode. The second electrode is a " N a t i o n a l " graphite rod—the purest graphite obtainable. Be sure to specify " N a t i o n a l " for your spectroscopic work. This b r a n d of g r a p h i t e is a c c o m p a n i e d by a "statement of p u r i t y " stating the trace-elements present. \ our analyst is thus forewarned against errors arising from unexpected spectral lines. UNION
CARBIDE The terms "National" and "Union Carbide" are registered trade-marks of Union Carbide Corporation NATIONAL CARBON COMPANY Division of Union Carbide Corporation · 30 East 42nd Street, New York 17, N.Y. Sales Offices: Atlanta, Chicago, Dallas, Kansas City, Los Angeles, New York, Pittsburgh, San Francisco. In Canada: Union Carbide Canada Limited, Toronto For further information, circle number 49 A on Readers' Service Card, page 99 A VOL.
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