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Saturday, 20 December 2014

DIRECT REDUCED IRON ( DRI)

Direct reduced iron i.e.. DRI is basically & technically expressed as iron -ore and these ore of iron which has been reduced to metal without melting it. Hot briquetted iron (HBI) is a densified form of DRI to facilitate its handling and transport. 

Process of manufacturing and process flow diagram 

In the process of production of DRI, we will get the solid-metallic iron directly from the solid iron- ore without any type of melting or fusion of metal.

Let us understand the production of direct reduced iron with the help of following figure.


Production process of DRI is either coal based or gas based. In DRI process the materials that we will use as raw material will be iron ore sized in the range of 10 – 30 mili-meter and Pellets of iron ore could also be used as raw material and must be noted that iron ore pellet will be produced in a separate unit called as pellet plant.

If we consider coal based unit the reactor for the reduction reaction will be take place is a shaft- furnace. This shaft furnace operates on the basis of counter current principle. 

We must be aware about the counter current principle, where feed material of iron ore will move in downward direction inside the shaft furnace due to action of gravity and will be reduced due to movement of reducing gases in upward direction. 

There are some fundamental about the shaft furnace that we have to be aware and these are as mentioned below.

  1. Pressure in shaft furnace (HYL process) = 5-6 bars
  2. Temperature in shaft furnace = 800-850 deg C

In case of gas based process, we will use gaseous fuels. This type fuels will have ability to reform / crack in order to provide mixture of CO and H2 gas. Normally we use high methane consisting natural gas. In case of coal based process non-coking thermal coal will be used. Carbon of coal will act same as a reducing agent in this process.


Let us go ahead towards next blog of manufacturing process of “Hot Briquetted Iron


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