Interaction of sulfur with iron compounds in sodium aluminate solutions

Reaction behaviors of sulfur and iron compounds in sodium aluminate solutions were investigated. The results show that iron compounds can remarkably remove the S2- but cannot get rid of S2O32-, SO32- and SO42- in sodium aluminate solutions. The removal efficiency of S2- using ferrous compound and ferric compound can reach 86.10% and 92.70% respectively when the iron compounds were added with a molar ratio of 2:1 compared with the sulfur in liquors at 100 degrees C. Moreover, several same compounds are formed in those two desulfurization processes with ferrous or ferric compounds, including erdite, hematite, amorphous ferrous sulfide, polymerized sulfur-iron compounds and ferric sulfate. The major difference between these two processes is that the erdite generated from ferrous compounds at the initial reaction stage will convert to a sodium-free product FeS2 at the subsequent stage.