Transport and transformation of mercury during wet flue gas cleaning process of nonferrous metal smelting

Abstract

Reducing mercury emission is hot topic for international society. The first step for controlling mercury in fuel gas is to investigate mercury distribution and during the flue gas treatment process. The mercury transport and transformation in wet flue gas cleaning process of nonferrous smelting industry was studied in the paper with critical important parameters, such as the solution temperature, Hg⁰ concentration, SO₂ concentration, and Hg²⁺ concentration at the laboratory scale. The mass ratio of the mercury distribution in the solution, flue gas, sludge, and acid fog from the simulated flue gas containing Hg²⁺ and Hg⁰ was 49.12~65.54, 18.34~35.42, 11.89~14.47, and 1.74~3.54%, respectively. The primary mercury species in the flue gas and acid fog were gaseous Hg⁰ and dissolved Hg²⁺. The mercury species in the cleaning solution were dissolved Hg²⁺ and colloidal mercury, which accounted for 56.56 and 7.34% of the total mercury, respectively. Various mercury compounds, including Hg₂Cl₂, HgS, HgCl₂, HgSO₄, and HgO, existed in the sludge. These results for mercury distribution and speciation are highly useful in understanding mercury transport and transformation during the wet flue gas cleaning process. This research is conducive for controlling mercury emissions from nonferrous smelting flue gas and by-products.

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