A STUDY OF THE THERMODYNAMIC BEHAVIOR OF MERCURY IN A WET FLUE-GAS CLEANING PROCESS

The behavior of mercury under conditions similar to a wet flue gas cle aning process has been discussed in terms of thermodynamic equilibrium . The spectrophotometric technique developed in our laboratory has bee n used to study the systems HgCl2 + HCl + H2O, HgCl2 + CaCl2 + H2O, an d SO2 + HgCl2 + HCl + H2O at 50 degrees C and atmospheric pressure in the absence of oxygen, A thermodynamic model presented in earlier comm unications is developed further. The substance-specific data required were extracted from literature and used without any further adjustment . The experimental results show that the soluble bivalent mercury (HgC l2) is completely reduced to elemental insoluble form through sulfur d ioxide, even in the presence of 0.1 M HCl (i.e., also in strongly acid ic solutions). This is also confirmed by the calculations done with th e thermodynamic model.