Quantitative Measurement of the Evaporation and Absorption of Mercury from Zn-Hg Amalgams

Abstract

Quantitative measurements have been performed on the evolution and absorption of mercury from Zn-Hg fluorescent lamp amalgams. Thermogravimetric analysis (TGA) under atmospheric pressure and vacuum (1.4-1.6 torr) conditions has been employed to study mercury evolution from Zn-Hg amalgam spheres. Conditions for the accurate determination of total Hg content of single Zn-Hg amalgam spheres under linear temperature ramp and hold conditions have been determined. Isothermal TGA has been used to measure both the short-term and long-term evaporation rate of Hg from single Zn-Hg spheres. In a related experiment, the total weight loss on 1500 individual Zn-Hg spheres was measured and statistically analyzed. Finally, using a special fulcrum apparatus the reversible evolution and re-absorption of mercury from Zn-Hg spheres was studied and characterized under simulated lamp conditions.