Gravimetric determinations of aluminum in iron ores are inaccurate, slow-, and tedious. .Z specific spectrophotometric method is described which is fast, direct, and accurate. A sodium carbonate fusion of the sample is dissolved in hydrochloric acid, diluted to volume, and an aliquot is taken for a blank and sample. Sodium mercaptoacetate is added to the sample to form a colorless complex with the iron and sodium Yersenate is added to the blank. Ammonium acetate buffer and stabilized Eriochrome C3anine R dye are added to 130th solutions. The red Eriochrome Cyanine R-aluminum complex which forms in the sample is measured against the hlanlc at 533 mp. Beryllium, background color of the dye, and other interfering elements are compcnsated for in the blank. When measured in a narrowband instrument, the complex obeys Beer's law up to 10% aluminum or higher.RAPID and specific method is needed for the determination
Germany, for assistance in the experiments.
LITERATURE CITED(1) Benedikt, "Analyse der Fette," p. 164, Berlin, 1892. (2) Sandermann, W., Bull. inst. pin., (3) No. 47, 137 (1937); Fette u. Seifen, 49, 582 (1942).(3) Storch, Ber. osterr. Gea. Forderung chem. Induatrie, to combine the new color test with the reaction of Storch-Moraw-9, 93 (1887).(4) Tschirch, A., and Stock, E., ''Die Harze," 3rd ed., Vol. 1, p. 284, ski and the diene titration. This i> shown in Table III.
Existing methods for the determination of beryllium require chemical separations from interfering elements. Direct photometric methods for the determination of beryllium in aluminum, steel, copper, titanium, and mixed oxides are described. Beryllium reacts with Eriochrome Cyanine R to form a red complex having a maximum absorbance at 512 µ at pH 9.8.Addition of Versenate and cyanide eliminates interfering ions. The methods are accurate and rapid.
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