Stabilization of mercury from mercury-containing waste with sulfur and pyrite
Elemental mercury (Hg0) is a metal with a number of atypical properties that have led to its use in a variety of anthropogenic processes. However, the same properties also have led to severe localized subsurface contamination in many of the locations where the mercury was used. By 2020, according to the provisions of the Minamata Convention on Mercury, countries that have ratified the Convention must phase out mercury-containing: batteries, switches and relays, mercury lamps, barometers, hygrometers, manometers, thermometers, and sphygmomanometers. To minimize the negative impact on the environment, technologies are used to convert mercury from mercury-containing waste into its most stable form, namely sulfide.The aim of this article is to develop a general approach to a wasteless method of converting mercury to mercury sulfide in solid waste, carried out under normal conditions. It is proposed to use the solid-phase reaction of mercury with sulfur/pyrite, carried out in ball mills. It was found that the highest percentage of mercury stabilization is achieved when the duration of interaction of mercury-containing waste with sulfur is 1.5 to 2 hours. The amount of added reagents (sulfur/pyrite) should be 3 times more than the amount of Hg0 contained in mercury-containing waste. In addition, it has been found that 30 to 60% of mercury oxide can be converted to mercury sulfide with excess sulfur/pyrite (mercury : sulfur/pyrite = 1 : 3) and grinding time 1.5-2 hours.