Abstract:

The disintegration caused by f-CaO is one of the main obstacles to the utilization of steel slag. The f-CaO come from the incomplete dissolution of the quick lime and the decomposition of tricalcium silicate. In terms of the f-CaO derived from the undissolved lime，it is necessary to strengthen the dissolution behavior of lime in the converter process. The lime reactivity plays a key role on its dissolution, and is closely related to its microstructure. The evolution behaviors of the reactivity and microstructure of quick lime under high temperature were investigated in this work. The lime samples were prepared in the laboratory, the microstructure was detected and analyzed by SEM, XRD and a mercury-injection instrument, and the reactivity was test according to YB/T 105—2005 standard. The results showed that， when temperature increased, the reactivity and porosity of the quick lime decreased，and the average diameter of pores increased. The CaO crystals grew gradually under the action of the grain boundary migration. The change of microstructure was closely related to the change trend of lime activity. On basic of the growth of CaO crystal and the decrease of the porosity, the lime activity decreased，which would obstacle the dissolution of quick lime during the steelmaking process and increase the content of f-CaO in the slag.

Key words: Times New Roman", ,", serif", font-size:10.5pt, ">quick limefont-size:10.5pt, ">；Times New Roman", ,", serif", font-size:10.5pt, ">reactivityfont-size:10.5pt, ">；Times New Roman", ,", serif", font-size:10.5pt, ">CaOfont-size:10.5pt, ">；Times New Roman", ,", serif", font-size:10.5pt, ">porosityfont-size:10.5pt, ">；Times New Roman", ,", serif", font-size:10.5pt, ">fTimes New Roman", ,", serif", font-size:10.5pt, ">-CaO