Development of a technology for immobilizing mercury in solid mercury-containing wastes

Abstract

According to United Nations Environment Programme technical guidelines there are two main chemical approaches to the immobilization mercury in chemical conversion to mercury sulfide and amalgamation. This article is devoted to the development of a general approach to the wastewater-less method of mercury conversion to mercury sulfide in solid waste carried out under normal conditions. The solid-phase reaction of mercury from sulfur carried out in ball or vibration mills, is proposed to use. The article presents an original technological scheme. It was found that, for energy efficiency, the duration of the interaction of mercury-containing waste with sulfur for 1.5–2 ​h is appropriate. The remaining mercury to safe concentrations in the approach developed by the authors is to be immobilized by the addition of oxidizing agents. An original method is devoted to removing reaction masses from apparatuses, which using a homogenizing medium based on bentonite. In the paper determined the optimal concentration of GNB-30 brand bentonite in the suspension (2.5% of the weight). The optimal amount of homogenizing medium is 80% or more. Additionally, It was found that from 30 to 60% of mercury oxide can be converted to mercury sulfide with an excess of sulfur (mercury: sulfur ​= ​1: 3) and a grinding time of 1.5–2 ​h. • Development of a technological scheme for the stabilization of mercury in waste. • Dependence of the Hg 0 immobilization % at reaction with S 8 on various parameters. • Selection of the amount of bentonite and water as a homogenizing medium. • Immobilization results of HgO in reaction with S 8 .