Source: Steel Times International
The world's first direct reduction process for iron ore concentrates from ore beneficiation that does not require any pre-processing, such as sintering and pelletising, has been developed by Primetals Technologies.
The development of the new process will benefit from Primetals' prior experience with its Finmet development and plant installations, the company claims.
FINMET technology is a fluidised bed reduction technology for direct reduction of iron ore using natural gas. It was developed by Primetals Technologies when it was known as Siemens VAI.
The new development is also based on a fluidised bed system as reducing reactor. Its development was based in part on the development of the FINMET plants, but was not a direct development. "The knowledge gained during Finmet's development aided the development of the new technology," said Primetals.
The new technology uses iron ore of a different size, a different pressure level and Hydrogen as reducing agent.
According to Primetals, the new technology can be applied to all types of beneficiated ore and particle sizes of 100% smaller than 0.15mm. The new process uses H2 from renewable energy or H2 rich gases from conventional steam reformers or H2 rich waste gases.
"This results in a low or even zero CO2 footprint," claims Primetals.
The new direct reduction plant is modular in design and has a rated capacity of 250kt/yr and per module, making it available for all sizes of steel plant. The plan is to set up a pilot plant for testing purposes at voestalpine Stahl Donawitz in Austria. Commissioning will be in Q2 2020.
According to Primetals, the use of Direct Reduced Iron (DRI) and Hot Briquetted Iron (HBI) is increasing as steelmakers look for ways to reduce greenhouse gas (GHG) emissions. At present, all available technologies require agglomeration, like pelletising, to produce DRI and HBI. Furthermore, reduced quality iron ore presents an additional challenge for steelmakers and results in the need to beneficiate the iron ores.
For CO2-free steelmaking to happen, a process using mainly H2 is considered most desirable.
The planned pilot plant will consist of a pre-heating-oxidation unit, a gas treatment plant and the actual reduction unit. Fine ore concentrate is heated to approximately 900 deg C in the pre-heating-oxidation unit and fed into the reduction unit. The reduction gas, H2, is supplied by an external gas supplier. A waste heat recovery system from the off-gas ensures optimal energy use and a dry dedusting system takes care of dust emissions from the processes involved. The hot direct reduced iron (HDRI) leaves the reduction unit at a temperature of approximately 600 deg C 'which can be subsequently used in an electric arc furnace or to produce HBI.
The pilot plant, says Primetals, will verify the break-through process and serve as a testing facility to provide the data basis for setting up an industrial-scale facility at a later date.