Chemistry of the Ironmaking by Blast Furnace Process Nov22

Chemistry of the Ironmaking by Blast Furnace Process...

Chemistry of the Ironmaking by Blast Furnace Process Liquid iron (hot metal) is produced in a blast furnace from the burden materials through a series of chemical reactions which are taking place at various levels in a blast furnace. When the burden materials descend from the top through the blast furnace stack, they are preheated by the ascending hot gases. Due to this preheat, the coke burns with great intensity when it reaches the level   of the tuyeres and comes in contact with the hot blast air. However due to the very high temperature (1650 deg C) and the large quantity of carbon (coke), the carbon dioxide formed is not stable and reacts with additional carbon to carbon monoxide. Hence the combustion of carbon in the blast furnace can be represented by the following equation: 2C+O2= 2CO This reaction is the main source of heat for the smelting operation and also produces the reducing gas (CO) that ascends into the furnace stack where it preheats and reduces most of the iron oxide in the burden as it descend to the hearth. Any moisture present in the hot air blast also reacts with the carbon of the coke. This reaction consumes heat and produces more reducing gas which is a mixture of CO and H2. Hence where high blast temperatures are available (1000 deg C to 1200 deg C), it is advantageous to keep the moisture content of the hot air blast uniformly at a high level by the steam additions in order to increase the amount of reducing gases ascending the furnace stack. C+H2O=CO+H2 The advantage of above reaction is that there is the introduction of hydrogen gas in the furnace reducing gases which decreases of the density of the ascending gases. This results...