Steelmaking with iron carbide

The concept of using iron carbide in steelmaking is not new. Tests were run several decades ago, using carbide made from ore, in steelmaking furnaces. The problem was that at that time, the need for the product was not clear and the economics of production were not favorable. In the early 1970's Frank M. Stephens, Jr., conceived the basis for the present process, and considerable development work has been done during the past decade to bring the carbide production process to its present state, with the first commercial unit now under construction. The process utilizes the following overall reaction to produce Fe[sub 3]C from ore: 3Fe[sub 2]O[sub 3] + 5H[sub 2] + 2 CH[sub 4][equals]2 Fe[sub 3]C + 9 H[sub 2]O. Hydrogen gas from a natural gas reformer is blended with natural gas to form the process gas that is recirculated through the fluid bed reactor, the cooling tower, to remove reaction product water, and back through the reactor again, after reheating. The closed loop nature of the process means that virtually 100% of the process reagents are utilized by the process. The only exception is that a small stream of the process gas is burned as fuel in themore » reheating step, in order to maintain the level of inerts in the process gas at an acceptable level. The quantity of the bleed stream is entirely dependent on the concentration of inert gases in the fuel supply.« less