Mangaluru  Blast Furnace Unit


(A Govt. of India Enterprise)
Telegram: KUDREORE
Telephone : 2408955, 2408916, Fax: 0824-2409366

Blast Furnace Process 

Image of Blast furnace processThe Blast Furnace unit has a blast furnace of 350 cum capacity of producing 227500 MT of Hot Metal per annum. The end product of the Blast Furnace Complex is foundry grade Pig Iron. The following raw materials are used in the process :

A special feature of  blast furnace process is that by using a feed of 100% Iron Ore pellets from KIOCL's Pellet Plant, 650 Tons per day of Hot Metal can be produced. For the present however, calibrated iron ore lumps of 10 - 30 mm size is being used as feed to the furnace.

The principle involved in Blast Furnace iron making is the thermo-chemical reduction of iron oxide ore by Coke into liquid iron at around 1500 degree C. The unwanted materials are removed in the form of liquid slag by addition of suitable fluxes. Raw materials are changed from blast furnace top and hot air is sent up from the bottom resulting in these thermo-chemical reactions.

The major raw materials used in the Blast Furnace operation are Iron Ore, Coke, Manganese Ore, Lime Stone, Quartizite and Dolomite, the last three being fluxes. The raw materials are received and stacked material wise in the stockyard. The materials required for the day's usage are then transferred into day bunkers by use of a conveyor system. The materials from the day bunkers are screened and weighed to the required size and quantity in batches. The undersize materials in the screening process are transferred into the fines bunkers for storage. The weighed batches are discharged into a conveyor in a pre-determined sequence and are transported to the blast furnace top for charging into the blast furnace.

The Blast Furnace top charging system is equipped with a double bell system to maintain the blast furnace top pressure. The raw materials are evenly distributed by using a rotary chute. The charging is carried out in batches as per a pre-determined sequence. The stock level indicator measures the level of raw materials inside the furnace and gives feed back for charging inputs. The entire charging system from screening to charging is fully automated.

The hot air required for the chemical reactions are blown into the furnace at an average rate of 43000 Nm3/hr by 2 HT motor driven blowers. The air before entering into the blast furnace is heated up to 1100 degree C using 3 stoves. The stove refractory checkers, which store heat, are heated by combustion of air and blast furnace gas inside stoves at optimum proportions. Blast Furnace gas is a by-product the furnace and carries around 20% CO which makes it a cheap and efficient fuel. The heat thus stored is passed onto the cold air blown by the blowers raising its temperature to 1100 Degree C making it suitable for use in the blast furnace.

The counter current movement of blast air and raw materials facilitates the reduction reaction of iron ore. The liquid iron (Hot Metal) produced collects at the bottom of the furnace above which liquid slag, which is higher, is collected. Both slag and hot metal are drained out through a top hole at regular intervals in Cast House. The hot metal is collected in 35 T capacity ladles where as the slag is granulated into powder form in a Slag Granulation Plant.

The Blast Furnace gas generated inside the furnace is cleaned of dust at Dust Catcher and Gas Cleaning Plant (GCP). Gas is washed of dust in GCP by water spray and the stoves and captive power plant use the cleaned gas as a cheap source of fuel. Any excess gas is bled off to the atmosphere after flaring.

Dedicated water pumping arrangements provides cooling water for the different cooling members inside the furnace. Cooling is essential in view of the refractory and shell life of the furnace. Another pumping system caters to the water requirements of the GCP.

The ladles carrying hot metal are transferred to a Pig Casting Machine (PCM) using a 50 Ton EOT crane. In the PCM, the hot metal is cast into 'Pig Iron' of max 8 Kg weight. The arrangement for this includes a double strand casting chain carrying 298 moulds in one strand. The strands are driven by an electric drive. The ladle is tited using the EOT crane and the hot metal is directed into the moulds by a runner system. Air-cooling and water-cooling is provided for the casting chain. The pig iron generated by the PCM is collected in three wagons from where it is lifted by electro-magnetic crane and transported to the pig storage yard and stacked grade wise for dispatch to customers.

The Pig Iron thus produced is sold to various customers all over India as per their specified requirements.

The Pig Iron thus produced is sold to various customers all over India as per their requirements.The Captive Power Plant(CPP) with two nos.each of 3.5MW Steam Turbine Generators caters to the power requirement of Blast Furnace complex.CPP uses Blast Furnace gas as the major fuel resulting in cost effective power generation.

At the BF Unit, two TG sets of 3.5MW are functioning. The TG sets are run by the steam from Boilers which are fuelled by Blast Furnace(BF) Gas generated by the  Blast Furnace.