Robert Meyrowitz 1973 <p>The ZrO_{<span>2</span>}&nbsp;content of rutile is determined spectrophotometrically&nbsp;by a direct pyrocatechol violet procedure. The sample is&nbsp;decomposed by potassium pyrosulfate fusion in a transparent quartz&nbsp;crucible, and a sulfuric acid solution of the melt is used for the&nbsp;determination at a pH of 5.1. Of the elements commonly present in&nbsp;rutile, only titanium and niobium occur in concentrations large enough&nbsp;to interfere. Titanium and niobium interference is overcome by adding&nbsp;the titanium and niobium contents of the sample to the standard&nbsp;zirconium solutions used for the standard zirconium curve. The&nbsp;absorbance is measured at 570 nm. Beer's law is obeyed within the&nbsp;range of 0.05-1.50 ppm ZrO₂. In the presence of 50 ppm TiO₂, the&nbsp;range is 0.15-1.50 ppm ZrO₂ . The tolerances of 47 elements were&nbsp;determined. The sensitivity is 0.0058 ug Zr/cm² . The variables in the&nbsp;method were studied, and typical results are given for commercial rutile&nbsp;concentrates.</p> application/pdf en U.S. Geological Survey Chemical analysis of rutile - a pyrocatechol violet spectrophotometric procedure for the direct microdetermination of zirconium article