Preperation Of Spherical Sponge Iron And Its Application Of Cd Removal From Polluted Water

With widespread expoitation and utilization of Cd minerals, lots of wastes containing Cadmium were released into environment and brought forth eco-risk to natural environment and human health. The sponge iron pheres were prepared through direct reduction. Cd removal process by sponge iron spheres being reducted by charcoal or H₂ under T₁ and T₂ temperature was explored through static and dynamic state tests. The following experiments were conducted and conclusions were drawn in this paper.Spherical sponge iron was reducted by charcoal and its capacity of removing Cd from wastewater. The sponge iron sphere possessing granular and intension was prepared through the process of palletizing, roasting, and direct recuction by charcoal. The results showed the Cd removal followed the first order reaction. The initial pH value made significantly impact on the Cd removal percentage. The removal percentage and rate constant were low when the pH value in solution was below 3. In contrast, the removal percent and rate constant were higher as pH value above 3. Cd removal percentage was reached a higher level as solid-liquid rate being 1:5 or 1:10. Whereas the quantities of Cd removal should be lower as solid-liquid rate being 1:20. The diameter of sponge iron made less impact on Cd removal from solution. The Cd removal percentage gradually decreased with the increasing of initial concentration, ultimately, the quantities of Cd removal increased slightly. In dynamic experiments, the column filled with sponge iron sphere exhibited favorable permeability. There was no sphere pulverization and conglutination between spheres. Contrast to the static state experiments, the Cd removal percentage in dynamic state experiment was lower, and the removal Cd quantity reduced to some extent.Spherical sponge iron was reducted by H₂ and its capacity of removing Cd from waste water. The similar sponge iron spheres were prepared by H₂ direct reduction under T₁ and T₂ temperature. The results showed these sponge iron sphere being better capability of removing Cd. The removal percentage and reaction rate constant were higher than those by sponge iron reducted by charcoal as the initial pH value below 3. In contrast, the sponge iron reducted by charcoal exhibited better capability of removing Cd as pH value being above 3. The results indicated that each of sponge irons could remove most of Cd in 1 h. The Cd removal rate constants by H₂ reduction sponge iron were slightly less than that of by charcoal reduction.