Hot air sintering (hot gas sintering) after the ignition of the
sintering machine, using hot air or hot exhaust gas of 300 to 1000 ° C sintering of iron ore sintering process. The conventional sintering process after sintering ignition, relying on the air at room temperature for sintering. Automatic regenerative role of the sintering process, the sintering temperature of the upper material layer, the lower sintering temperature is high, so the upper sintering often inadequate, insufficient liquid, resulting in proceeds of sinter strength World Steel Pipe News , and the formation of many back to mine, while the lower part due to the sintering temperature, melt, sinter reducibility deteriorate World steel pipe network editing . The ideal sintering system along the material layer of a high degree of sintering temperature uniformity. The hot air sintering is to continue to provide the material layer after ignition, the hot air to provide heat to supplement the deficiencies of the upper heat, so that the upper and lower material layer sintering temperature is more uniform.
Effect of hot air sintering the material layer of the upper part of the sintering temperature increased, the liquid increased, reduce liquid viscosity, is conducive to mineral fully crystalline glass phase content decreased, thereby improving the the sintering overall yield and sinter strength. In addition. Instead of cold to the hot air pumped into the layer of air and thermal sintering temperature difference reduced to reduce the cooling rate, reduce the thermal stress to promote the strength of sinter. Hot air sintering can reduce solid fuel consumption, reduce the melt, the lower of FeO, thereby enhancing the reduction of the sinter. 1000 ° C hot air sintering, solid fuel savings of 20% to 30%, the total heat consumption decreased by 10% to 13% performance improvement of sinter metallurgy, powder large amount of reducing However, hot air sintering sintering rate of decline, and thus production to decline in the permeability of the material layer does not improve conditions.
Conditions hot air temperature, heating time and the hot air in the oxygen content had a greater influence on the effect of hot air sintering. Suitable for the hot air temperature depends on the supply and price of the ore fFJ'I ~: quality, gas and solid fuel. Higher air temperature can save more of the solid fuel, to reduce the FeO content in sinter, and increase the reduction, but the impact of the sintering machine output; low air temperature of less than above purposes, generally 900 the ℃ effects. The heating time should be able to ensure that the upper heat and lower heat without enough surplus principle of. The heating time is too long, too much heating, solid fuel can be reduced, but the gas consumption to increase, the total heat consumption increase, while the bed temperature to improve the resistance of the material layer increases, resulting in the decline. General heating time to 4 ~ 5min (ie, accounting for sintering one-third of the time) is appropriate, otherwise a greater impact on yield. The hot exhaust gas oxygen content of not less than 10.5 percent, or solid fuel consumption to increase, with H2O and CO2 should not be too high.
Hot air sources of hot air sources of 3 ways: 1 copy hot stove or other forms of heat exchangers to generate hot air. This method allows the hot air temperature is adjustable, so that the surface temperature of the car is easy to achieve uniform distribution and full oxygen content in the hot air is beneficial to both improve the yield and quality of the sinter, but investment in infrastructure and high operating costs. 2 ways to set the heater igniter or holding furnace, high temperature exhaust gas combustion. The advantage is the simple equipment, easy to operate, safe and reliable, the effect is also apparent, but the hot exhaust gases to reduce the oxygen content, production and desulfurization of the sintering machine. The three kinds of way to the end of the sintering machine or cooler thermal waste stretch. This program will not be too much equipment, the method is simple, but the hot air temperature is low, generally only 200 ~ 300 ℃, the effect is lower than the above two programs.