Burnt lime is an important material in steelmaking and its activity degree is a key factor for liquid steel quality. The burnt lime was made by the calcination of limestone in a high pressure electric furnace. The bur...Burnt lime is an important material in steelmaking and its activity degree is a key factor for liquid steel quality. The burnt lime was made by the calcination of limestone in a high pressure electric furnace. The burnt lime mineralogical phases and micro-morphologies were characterized by X-ray diffraction （XRD） and field emission scan- ning electron microscopy （FE-SEM）. The burnt lime activity degree was determined by acid-base titration, the burnt lime pore distribution was measured by mercury intrusion porosimetry （MIP）, and the thermal effect of a mixture of burnt lime and slag was measured by differential scanning calorimetry （DSC）. The results showed that the CaO grain size and pore size of burnt lime made under high pressure were larger than those of burnt lime made under atmos- pheric pressure. The CaO grain size and pore size increased and the laminate phenomenon also occurred clearly under high pressure. The activity degree of burnt lime made under high pressure was greater than that made under atmos- pheric pressure. The maximum activity degree was 437 mL for burnt lime made under a pressure of 0.4 MPa. For the same ratio of CaO to SiOz, the melting temperature, hemisphere temperature and fluidity temperature of slag decreased with increasing burnt lime activity degree. The higher the activity degree the burnt lime had, the better the slag forming occurred. It was advantageous for -2CaO · SiO2 and 3CaO · SiO2 forming at lower temperatures if the burnt lime activity degree was increased.展开更多
基金Sponsored by National Natural Science Foundation of China(51174075,51274084)Natural Science Foundation of Hebei Province of China(E2012209024,E2014209157)
文摘Burnt lime is an important material in steelmaking and its activity degree is a key factor for liquid steel quality. The burnt lime was made by the calcination of limestone in a high pressure electric furnace. The burnt lime mineralogical phases and micro-morphologies were characterized by X-ray diffraction （XRD） and field emission scan- ning electron microscopy （FE-SEM）. The burnt lime activity degree was determined by acid-base titration, the burnt lime pore distribution was measured by mercury intrusion porosimetry （MIP）, and the thermal effect of a mixture of burnt lime and slag was measured by differential scanning calorimetry （DSC）. The results showed that the CaO grain size and pore size of burnt lime made under high pressure were larger than those of burnt lime made under atmos- pheric pressure. The CaO grain size and pore size increased and the laminate phenomenon also occurred clearly under high pressure. The activity degree of burnt lime made under high pressure was greater than that made under atmos- pheric pressure. The maximum activity degree was 437 mL for burnt lime made under a pressure of 0.4 MPa. For the same ratio of CaO to SiOz, the melting temperature, hemisphere temperature and fluidity temperature of slag decreased with increasing burnt lime activity degree. The higher the activity degree the burnt lime had, the better the slag forming occurred. It was advantageous for -2CaO · SiO2 and 3CaO · SiO2 forming at lower temperatures if the burnt lime activity degree was increased.
