Analysis of steels and alloys by direct spectrophotometric method to determine the rare earth content

Studied is the effect of interfering elements (Fe, Cr, Cu, Ni, Zr, V, Al, Mo, Ti, W and others) upon reaction of rare earth elements with arsenazo 3 without addition of masking substances and in the presence of complexon 3 and hydrogen peroxide. Introduction of high concentrations of arsenazo 3 permitted to establish a new region of formation of REE stable complexes at pH 1.0-1.3. In the presence of complexon 3 and H2O2 REE reaction with arsenazo 3 is selective as to Fe(3), Cr(3), Cu, Ni, Zr, Al, Ti, W, phosphates, sulphates, nitrates, tartrates. The method of direct spectrophotometric determination of REE in steels and alloys is developed. It is established that elements from La to Dy, as well as Y can be determined with sensitivity 5x10-3%, for other REE sensitivity decreases which is the result of partial destruction of heavy REE compounds with arsenazo 3 by complexon 3