Characteristics of Mercury Release during Flue Gas Desulphurization Gypsum Reuse

An investigation of the mercury release characteristics of four kinds of FGD gypsum during the heating process was conducted at a heating rate of 40°C/min in the air, in order to analyze the characteristics of mercury release during calcining and the heating process of gypsum products with FGD gypsum as a raw material. The results indicate that the main suitable temperature range for mercury discharging is between 200°C and 400°C during the heating process of FGD gypsum, with the mercury release rate falling off with a further increase of temperature. Further study on the distribution of mercury release showed that elemental mercury (Hg⁰) discharge is greater than divalent mercury (Hg²⁺) in the heating process of the FGD gypsum.