Study on the Preparation of Filler Using Iron Tailings for Constructed Wetlands System and Its Mechanism of Pore Formation
In order to solve the problem of iron tailings accumulation,the filler with good properties for constructed wetlands FITCWS was prepared using iron tailings and wood dust as the main raw materials.During calcination,the main mineral composition of the FITCWS were changed from feldspar and hornblende to augite.Temperature(T),the amount of wood powder(η),the particle size of wood powder(dw)and tailings(di)had impacts on the physical properties of FITCWS.The main influencing factors of water absorption and particle strength were T,the main influencing factors of specific surface area and pore volume were dw and di,and the main influencing factors of pore width were dw,T and di.With the increase of T,the particle strength of FITCWS was increased also,however the water absorption was opposite.The specific surface area,pore volume and pore width were increased with the decrease of dw and di,whereas the surface of FITCWS particles became smooth.The optimal experimental scheme for the preparation of FITCWS was as follows:η was 0.3,T was 1200℃,dw and di were both 200-250 of mesh(58-74 μm).The water absorption rate,particle strength,specific surface area,pore volume and pore width of prepared FITCWS were 44%,115.9 N,6.932 m2/g,0.017 cm3/g and 3.169 nm,respectively,and the pores were narrow and permeable.
iron tailingsconstructed wetlandsfillerspecific surface areapore volumepore width
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