| AOD slag contains a lot of calcium oxide and silica,its composition properties are similar to cement,and it has good recycling value.AOD slag contains a small amount of heavy metal elements such as Cr and Ni.Under natural conditions,it has a certain leaching toxicity.Therefore,the treatment and comprehensive recovery of AOD slag has received more and more attention.Taking AOD slag as the research object,the long-term dynamic leaching experiment method was used to study the effect of leaching solution acidity and leaching atmosphere on AOD slag.The effects of long-term long-term dynamic leaching on the phase change of AOD slag were studied by XRD analysis,SEM/EDS and mineral phase quantitative adiabatic method.The results of long-term dynamic leaching experiments showed that the concentration of Cr in the leaching solution of AOD slag changed greatly.The maximum concentrations of Cr6+and total Cr in the leaching solution under acidic leaching conditions were 313.88μg/L and 340.83μg/L,respectively,which were greater than neutral and alkaline leaching conditions.The leaching performance is mainly Cr6+;the leaching rate of Cr6+is up to 34.45%,2.3 times and 4.4 times under neutral and alkaline conditions,and the maximum Cr leaching rate is 50.36%under neutral and alkaline conditions.1.78 times and 3.59 times.The results of mineral phase analysis indicate that the main mineral phases of AOD slag are attapulgite,gunite,magnesite,dicalcium silicate and perovskite.Cr is present in the form of an oxide in the initial miner-al phase such as tobermorite and dicalcium silicate.After the AOD slag is leached,a C-S-H gelling phase and a leaching secondary phase such as calcium carbonate are formed.Acidic leaching is more conducive to the dissolution of tobermorite;acid leaching and alkaline leaching promote hydrolysis of dicalcium silicate;The C-S-H phase and calcium carbonate were produced under leaching conditions and gradually increased with the leaching time.Figure 33;Table 4;Reference57. |
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