| The crystallization kinetics of stainless steel slag glass was studied in this paper.The slag glass samples with different Cr2O3 content and different basicity were prepared using pure chemical reagents by melting at high temperature and then quenching in oil. The crystallization behavior were investigated by using Differential scanning calorimetry(DSC), X-ray diffraction(XRD), Scanning electron microscope(SEM)- Energy dispersive spectrometer(EDS) and Fourier transform infrared spectrometer analysis(FTIR).(1) The main components of stainless steel slag were CaO、MgO、SiO2、Al2O3、Fe2O3 and Cr2O3 which were determine by relevant literature and earlier researches in our researching group. Pure chemical reagents used are basis on the weight percent.The basic simulated stainless steel slag samples were obtained by grinding the raw materials until they were smoothly blended, melting at high temperature then quenching in oil with different basicity such as 0.6、0.8、1.0、1.5、2.0 and with 2 wt%Cr2O3 and without Cr2O3.(2) The probe trial to prepare basic simulation stainless steel slag showed that if the slag contained 4wt% Cr2O3, the crystal phases was generated in simulation stainless steel slag with basicity of 1.0、1.5 and 2.0; the crystal phases also appeared if the basicity of basic simulation stainless steel slag was 1.0 with lower MgO or Fe addition; the main crystal phase was determined by the composition of Cr2O3,amorphous phase appeared at low Cr2O3 composition such as ≤ 2% at the same time the basicity could be set at 0.6、0.8、1.0.(3) The study of basic simulation stainless steel slag with different Cr2O3 content were carried out at 1660°C for 2h and then quenched in oil. The samples, respectively,heat-treated temperature were 1000°C, 1200°C and 1340°C, then the heat-treatedsamples were analyzed by XRD, DSC and SEM-EDS. The results showed that it is helpful to form spinel in slag with basicity 1.0 and 4wt% Cr2O3. The precipitated phase changed depending on Cr2O3 addition, and the variation of crystal type might be related to the basicity of glass. The DSC results suggested that the first crystallization peak was ranged at 1100°C-1200°C, the second peak was ranged at 1200°C-1400°C.(4) The study of basic simulation stainless steel slag with different basicity were carried out at 1660°C high temperature melting, insolated at 1660°C for 2h and then quenching in oil. The samples heat-treated at 1150°C were analyzed by XRD, DSC and SEM-EDS. The results showed that amorphous phase presented in quenching slag was the main phase in 0.6 and 0.8 basicity; CaSiO3 and Ca2Mg(Si2O7) crystals were precipitated in basicity lower than 1.0, no matter with or without Cr2O3; it will be beneficial for the formation of Ca3Mg(SiO4)2 and Ca2SiO4 in slag at basicity 1.5 and2.0; if the basicity greater than 2.0, crystal were precipitated in slag samples no matter with or without Cr2O3.(5) Crystallization dynamics parameters were calculated using Kissinger Equation under non-isothermal condition. The results showed that there were two kinds of crystals precipitated in simulation stainless steel slag without Cr2O3, the activation energy Ep1 is 258.03 kJ/mol,Ep2 is 231.07 kJ/mol; there were also two kinds of crystals precipitated in simulation stainless steel slag with 2% Cr2O3, the activation energy Ep3 is 1035.15 kJ/mol,Ep4 is 278.85 kJ/mol. The crystallization of capacity was determined by the content of Cr2O3 in the simulation stainless steel slag samples. It will be easier to precipitate crystal at Tp2 temperature than Tp1 temperature. The parameter n is 2, it means that the crystallization mechanism is integral crystallization method. |
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