Separation and determination of small quantities of aluminum in steel

Abstract

A m ethod is described for d etermi nin g s mall a mounts of a luminum (0.01 to 0.3 percent) in tainless a nd carbon s teels. A p erchlorie-sulfmic acid solution of th e steel is electrolyzed ill a m ercury catll ode cell to remov e most of the iroll , and an extraction with chloro form is m ade to remove elements such as alumi num, residu al iron , a nd titan iu m a s cupferrates from a solut. ion buffered at pH 3.5. These elements are conv erted from cupferrate to perchlorates; a ll excep t aluminum are t hen extracted as cupferrates with chloroform from 4 N hydrochlori c acid . Aluminum in t he acid solution is d eter.min ecl photo met ricall y wi t h a luminon (ammonium a urintricarboxylate) at a wave leng t h of approximately 540 millimicrons. An acc uracy of ± 0.005 percent a luminum is indi catecl .

Ferrous Metallurgy

“…ALUMINUM Aluminum continued to be determined by gravimetric (66), volumetric (33), colorimetric (18,26,69,139,221,308,339), and spectrometric (140,315,347) methods. In most procedures, the measurement of aluminum was made after separation from interfering elements with the mercury cathode or by solvent extraction.…”