Applications A. Extraction of iron from its oxides. In a blast furnace, oxide oes of iron after concentration through calcination or roasting are mixed with limestone and coke, a fed from its top. Hot air is blown from the bottom of the furnace and coke is burnt to give temperature up to about 2200 Kelvin in the lower point itself. The burning of coke therefore supplies most of the heat required in the process and will be oxidized to seal. The seal and heat moves to upper part of the furnace. The upper part, the temperature is lower and the iron oxides, F2 or 3 and F3 or 4, coming from the top are reduced in steps to FEO. Some stone is also decomposed to CLO which removes silicate impurity of the ore as slag. The slag is in molten state and separates out from iron. Thus, the reduction reactions taken place in the lower temperature range and in the higher temperature range depend on the points of corresponding intersections in the delta rg- versus t-plots. These reactions can be given as follows. At 500 to 800 Kelvin, lower temperature range in the blast furnace. 3 F2 or 3 plus CO gives 2 F3 or 4 plus CO2 equation 11. F3 or 4 plus 4 CO gives 3 F4 plus 4 CO2 equation 12. 3 2 or 3 plus CO gives 2 FEO plus CO2 equation 13. At 900 to 1500 Kelvin, higher temperature range in the blast furnace, C plus CO2 gives 2 CO equation 14. FEO plus CO gives FEO plus CO2 equation 15. The iron obtained from blast furnace contains about FEO and CO and many impurities in small amount. Example S-P-S-I-M-N.