Mercury Disposal via Sulfur Reactions

Abstract

A high-shear blending technique for converting large volumes of elemental mercury into mercuric sulfides has been evaluated. The two basic forms of mercuric sulfide (cinnabar and metacinnabar) were prepared by triturating stoichiometric ratios of elemental mercury and sulfur. X-ray analysis and scanning electron microscope techniques confirm the existence of both forms of mercuric sulfide. These sulfides passed the Toxicity Characteristic Leaching Procedure test for mercury vapor-phase requirements and thus meet waste acceptance criteria for handling/storage of low-level radioactively contaminated mercury. Black mercuric sulfide (metacinnabar) is the recommended target product in the conversion of mercury to mercuric sulfide, because it is easier and safer to produce. Zinc-mercury amalgams were also prepared and compared with the sulfides in terms of meeting processing and storage requirements for mercury mixed waste. Mercury loading for both forms of mercuric sulfide is significantly higher than mercury loading in a typical transition metal amalgam.