Zinc concentrate internal circulation technology for elemental mercury recovery from zinc smelting flue gas

As most of the purposed synthesized mercury sorbents are expensive and insufficient for capturing mercury from the flue gas with ultrahigh concentration of Hg-0 and SO2 in smelting processes, the application of sorbent injection for mercury removal in zinc smelting was extremely restricted. In this work, Zinc concentrate (ZC) ore, one of the raw materials for smelting, was developed to capture gaseous Hg-0 from zinc smelting flue gas. The average Hg-0 adsorption capacity of ZC was greater than 2 mg.g(-1), even better than some synthetic binary sulfide sorbents. Meanwhile, ZC presented a good resistance to H2O and SO2 at 60-100 degrees C. Higher ratio of Cu element in ZC ores can result in better Hg-0 adsorption performance due to the increase of active site S-n(2-) derived from the oxidation of S2- by Cu2+. After capture Hg-0, spent ZC can be reused as raw material for zinc production, eliminating the generation of waste sorbent. This technology can as a co-benefit of condensation device to deeply purify mercury pollutants, and the excessive gaseous Hg-0 will be removed from the system by condensing into liquid mercury. Moreover, such ZC cycles offers a specific strategy for gaseous Hg-0 recovery in other nonferrous smelting industries.