Extraction Of Iron

Extraction of Iron Iron is about 21 % of total metal of earth’s crust and 6.2 % of total elements. It belongs to transition group of the periodic table. Its electronic configuration is 2,8,8,6,2. Some important ores of Iron are listed below:i). Hematite Fe2O3 ii). Magnetite Fe3O4 iii). Limonite Fe2O3.H2O iv). Siderite FeCO3 Hematite:Hematite, mineral and the most abundant ore of iron, composed of ferric oxide, Fe2O3. It is widely distributed over the world, occurring in rocks of all ages. In the United States hematite makes up about 50 percent of all the iron ore mined. The chief iron-ore districts in the U.S., and probably the most important hematite regions in the world, are located along the shores of Lake Superior in Michigan, Wisconsin, and Minnesota. Extensive deposits are also found in the Appalachian region extending from New York to Alabama, with particularly noteworthy deposits in eastern Tennessee and northern Alabama. Hematite occurs in rhombohedral crystals, called specular iron in massive formations, and in earthy forms, called red ocher. The crystals are translucent, range in color from dark gray to black, and have a brilliant metallic luster; the earthy varieties are lusterless and red. Main steps involved in extraction of iron from its ore hematite are given below:1.) Concentration of ore:- First of all ore is crushed into minute particles and the crushed ore is concentrated by gravity separation method. 2.) Calcination:- Concentrated ore is calcinated in furnace. During calcinations moisture is removed. Impurities like Sulphur changes into Sulphur dioxide and Arsenic into arsenic oxide, Phosphorus to Phosphorus oxide all escape out in the form of gases. Due to presence of some ferrous carbonate iron changes into iron oxide. 3.) Smelting:- Iron oxide is reduced with carbon. Process of smelting is done in a furnace. Calcinated iron is added in blast furnace along with coke. Coke serves as fuel as well as reducing agent. Lime is also added in furnace which serves as flux. The following reactions takes place in the furnace:a). At the base of the furnace:- Coke reacts with oxygen to produce Carbon dioxide which moves up and lot of heat is produced.

C+O2

CO2

As the Carbon dioxide moves upward it is brought in contact with coke and get converted into Carbon monoxide.

CO2+ C

2CO

At this zone temperature is 1475-1575 K.

b). In the middle of the furnace:-Here temperature is about 1075 to 1275 K. In this region calcium carbonate decomposes to produce calcium oxide and carbon dioxide. Calcium oxide so produced combines with silica to form slag.

CaCO3

CaO+CO2

CaO+SiO2

CaSiO3 Calcium Silicate (slag) c). At the top of the furnace:- In the top of furnace the Iron oxide react with carbon monoxide to give liquid iron which moves towards the bottom of the furnace and settled there. This iron is called cast iron.

Fe2O3+3CO

Fe+CO2

PROJECT SUBMITTED BY:-GOVT. GIRLS SEC. SCHOOL URMAR TANDA(HOSHIARPUR) SUBJECT OF THE PROJECT:-EXTRACTION OF IRON ORE