Thermohardening modes in the oxidizing atmosphere of burnt pellets with residual carbon manufacture for blast furnace melting
Effective modes of green pellets thermostrengthening have been worked out and selected, characteristic property of the pellets being solid fuel rolled up inside them. The use of the obtained material in the blast furnace will result in considerable savings of expensive and scarce coke. The developed technology makes it possible to receive burned pellets with maximum residual carbon in the finished iron ore product. The received results have shown that higher heating rate must be used to heat dried pellets (500°C/min. instead 100°C/min.) and still higher cooling rate to cool the burned pellets (600°C/min. instead 100°C/min.) in an oxidizing atmosphere. Owing to these changes in the process the amount of residual carbon in the finished product increases from 0.7 to 3.5%. Comparative characteristics of the technological parameters of production and metallurgical properties of the produced lumped iron ore (sinter and pellets) and the pellets with residual carbon show, that the developed iron material with residual carbon not only meets all the requirements for the blast furnace melting, but also has better metallurgical properties than the oxidized burned pellets