Posted on 10 Oct 2016
The market share of the Metallurgy Division of AUMUND Fördertechnik GmbH is growing. A new specialised conveyor for HDRI, a 116 m long BZB-H-I 900/400 designed for a capacity of 323 t/h hot DRI at 750 °C, has just been supplied to Tosyali’s new steel plant in Algeria.
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The decisive factor in the award of the order to AUMUND Fördertechnik was the technical solution. AUMUND is putting its patented bucket conveyor into operation in Algeria. The improved sealing of this conveyor protects the material from environmental influences; the inert system prevents the re-oxidisation of the highly reactive bulk material and permits the transportation of the DRI without great losses in the level of metallisation.
“In order to produce the same amount of steel a far smaller energy input into the electric arc furnace is required. Therefore the tap-to-tap cycles are reduced and productivity can increase by up to 20 percent”, explains AUMUND Project Manager, Christian Niedzwiedz.
The AUMUND specialised conveyor for HDRI will be used as the connection between the Midrex shaft furnace and an electric arc furnace.
Tosyali is currently building the world’s largest DRI plant, located in Bethioua, Algeria, with Midrex technology. The new direct reduction plant will have a production capacity of 2.5 million tons of DRI and have the option to produce either hot or cold DRI (HDRI or CDRI).
The latest generation specialised conveyor was first implemented at one of the largest steel production plants in India in 2013, and has since been patented.
This BZB-H-I conveyor has a capacity of 165 t/h. In this application the material also comes from a Midrex shaft furnace.
Advantages of hot charging
The conveying of hot DRI (HDRI) to the electric arc furnace has considerable advantages. The requirement for electrical energy per ton of molten steel is
significantly reduced. The energy reduction is achieved because the input material retains the heat that it already has when it comes out of the DRI production process. Therefore less energy is needed to melt it down, and automatically the melting process takes less time. Because the material is filled directly into the furnace, the lid does not need to be opened, so even more time and energy is saved.
“Compared with cold charging, the conveying of HDRI saves up to 6% on electrode consumption. The tap-to-tap times and primary energy source carbon requirements are reduced, so this in turn reduces the CO 2 emissions”, according to Christian Niedzwiedz. When HDRI enters the furnace at approx. 600 °C the energy saving is more than 120 kW per ton of molten raw steel.
