Effects of Mg2+ on the bivalent mercury reduction behaviors in simulated wet FGD absorbents.

This paper studied the bivalent mercury reduction behaviors after Mg(2+) addition in the simulated Ca-based and Dual-Alkali flue gas desulfurization (FGD) absorbents. Experimental results showed that the reduction of bivalent mercury was increased in the Ca-based FGD absorbent and inhibited in the Dual-Alkali FGD absorbent. It was proposed that the former was mainly attributed to the enhanced dissolution and recrystallization of CaSO(3) particles by Mg(2+) addition, which provided more active surface for mercury adsorption and reduction, whilst the latter was mainly due to the formation of neutral MgSO(3)(0) ion pair, which tended to lower the active sulfite concentration in the simulated solution.