Quantitative Spectrochemical Determination of lead and Zinc in Ores ISIDORE SCHKOPPER AND ISIDORE ADLER U . S. Customs Laboratory, New Y o r k , N. Y .
A spectrochemical method applicable to the determination of 0.05 to 6Yo of lead and 0.05 to 69% of zinc in antimony, tin, and copper ores is described. The specific examples discussed are the determination of lead and zinc in antimony sulfide and oxide ores., This method employs the high amperage direct current arc, external standards, lithium carbonate buffer, and fine wiremesh screen light filters. Accurately weighed samples and carefully controlled arc conditions make possible the elimination of an internal standard. A statistical study of the results obtained by this method compared with the results obtained by chemical analysis indicates no significant difference. X I T E D States Customs Laboratories make numerous determinations of the lead (Public Law No. 725, June 19, 1948, suspends import duties on lead-bearing ores until June 30, 1949) and zinc content of a \vide variety of ores such as antimony, copper, tin, and tungsten (4). Available chemical procedures are both tedious and time-consuming, and they involve difficult fusions and troublesome separations, particularly where the concentrations of lead and zinc are IOU.. This paper deals with a spectrochemical procedure which has to a large extent replaced the chemical methods in this laboratory and which has a t least comparable accuracy as well as great advantage in time economy.
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