化工类外文翻译---高炉炼铁-化学工程(编辑修改稿)

化工类外文翻译---高炉炼铁-化学工程(编辑修改稿)内容摘要：

volatile matter such as oil and tar are removed. The cooked coal, called coke, is removed from the oven after 18 to 24 hours of reaction time. The coke is cooled and screened into pieces ranging from one inch to four inches. The coke contains 90 to 93% carbon, some ash and sulfur but pared to raw coal is very strong. The strong pieces of coke with a high energy value provide permeability, heat and gases which are equired to reduce and melt the iron ore, pellets and sinter. The final raw material in the ironmaking process in limestone. The limestone is removed from the earth by blasting with explosives. It is then crushed and screened to a size that ranges from inch to inch to bee blast furnace flux . This flux can be pure high calcium limestone, dolomitic imestone containing magnesia or a blend of the two types of limestone. Since the limestone is melted to bee the slag which removes sulfur and other impurities, the blast furnace operator may blend the different stones to produce the desired slag chemistry and create ptimum slag properties such as a low melting point and a high fluidity. All of the raw materials are stored in an ore field and transferred to the stockhouse before charging. Once these materials are charged into the furnace top, they go through numerous chemical and hysical reactions while descending to the bottom of the furnace. The iron ore, pellets and sinter are reduced which simply means the oxygen in the iron oxides is emoved by a series of chemical reactions. These reactions occur as follows: 1) 3 Fe2O3 + CO = CO2 + 2 Fe3O4 2) Fe3O4 + CO = CO2 + 3 FeO 3) FeO + CO = CO2 + Fe or FeO + C = CO + Fe At the same time the iron oxides are going through these purifying reactions, they are also beginning to soften then melt and finally trickle as liquid iron through the coke to the bottom of the furnace. The coke descends to the bottom of the furnace to the level where the preheated air or hot blast enters the blast furnace. The coke is ignited by this hot blast and immediately reacts to generate heat s follows: C + O2 = CO2 + Heat Since the reaction takes place in the presence of excess carbon at a high temperature the carbon 7 dioxide is reduced to carbon monoxide as follows: CO2+ C = 2CO The product of this reaction, carbon monoxide, is necessary to reduce the iron ore as seen in the previous iron oxide reactions. The limestone descends in the blast furnace and remains a solid while going through its first reaction s follows: CaCO3 = CaO + CO2 This reaction requires energy and starts at about 1600176。 F. The CaO formed from this reaction is used to remove sulfur from the iron which is necessary before the hot metal bees steel. This sulfur emoving reaction is: FeS + CaO + C = CaS + FeO + CO The CaS bees part of the slag. The slag is also formed from any remaining Silica (SiO2), Alumina (Al2O3), Magnesia (MgO) or Calcia (CaO) that entered with the iron ore, pellets, sinter or coke. The liquid slag then trickles through the coke bed to the bottom of the furnace where it floats on top of the iquid iron since it is less dense. Another product of the iron。