Preparation and Kinetic Study of High-Calcium Adsorbent from Acetic Acid Modified Steel Slag
To improve the comprehensive utilization of steel slag resources and reduce the CO2 emission in the process of iron and steel smelting,the leaching and high-temperature sintering process was used to modify the steel slag of converter.Through the leaching process,the calcium-containing components were prepared into calcium-based adsorption materials,and the iron-containing components of the leaching residue were enriched and recovered.The effect of leaching parameters on the composition of calcium-based adsorbent was investigated.To investigate the leaching process of calcium in steel slag particles,the leaching rate of steel slag particles in a weakly acidic solution was analyzed by using a shrinkage core model.The phase structure change of leaching residue modified by high temperature was studied,and the transformation rule of iron elements was analyzed.In addition,the phase structure of the calcium-based material was checked by XRD and SEM observations.Finally,the adsorption properties of the calcium-based materials were measured.The results show that the leaching temperature and acetic acid concentration have a great influence on the CaO content in the calcium-based materials.Under larger particle size,the optimal leaching parameters were acid concentration 1 mol/L,solid-liquid ratio 1∶10,leaching temperature 70 ℃,and leaching time 2 h.Under these conditions,the CaO content reached 86.3％.Under stirring conditions,the calcium leaching process is controlled by internal diffusion.In the range of 40-70 ℃,the rate control steps of the calcium leaching process did not change and were still controlled by internal diffusion.The CaO purity of the prepared calcium-based material is higher,and the adsorption capacity of CO2 increases with the increase of CaO content,which can reach up to 60.6 mg/g under atmospheric pressure.After the leaching residue was modified at high temperature,the Ca2Fe2O5 phase was transformed into the spinel phase(Fe3O4,MgFe2O4),and calcium and iron elements were separated,enriched,and recovered well.
steel slagCO2 emission reductioncalcium-based adsorbentmetal element recoveryacid leaching kinetics
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