Flame Spectrophotometric Analysis of Glasses: II, Calcium, Magnesium, and Barium, Including the Alkalis

The amount of calcium, magnesium, and barium, as well as of the alkali elements, in many glass compositions can be rapidly estimated with a flame spectrophotometer. Since the flame emission of the alkaline-earth elements is altered by such glass constituents as aluminum, iron, titanium, phosphorus, and zirconium, these elements should be removed, before flame analysis, by precipitation with ammonium hydroxide. With the elimination of the hydrous oxides and with corrections for the background interferences in the flame emission of the alkaline earths by the elements remaining, satisfactory flame analyses can be obtained. The mean difference between chemical and flame results for a series of 27 glasses of widely varying composition is approximately 0.15% for each element determined.