Brazilian diversified mining group Vale, the world’s second largest miner in terms of market capitalisation, has announced that it has started up a demonstration plant to test and further develop a unique Brazilian technology which can produce pig iron without using a traditional blast furnace.
The demonstration plant, located at Pindamonhangaba in São Paulo state, started operation on September 12 and has an annual production capacity of 75 000 t. This new technology promises higher productivity and flexible use of raw materials while cutting steel production costs by up to 30%.
It is forecast that the new technology will cut steel plant carbon dioxide emissions by 5%, particulate emissions by as much as 85% and nitrogen oxide emissions by up to 95%.
The development of the technology started 35 years ago and has cost some 250-million reais (R$ – around R1.13-billion) so far, of which about R$130-million (R585-million) has been contributed by Vale since it joined the project in 2009.
The new technology is called tecnored, and its further development is now the responsibility of Tecnored Desenvolvimento Tecnológico (Tecnored). Vale is the biggest shareholder in this enterprise, holding 43.04% of the equity, with 31.70% being held by BNDESPar (the investment arm of Brazil’s National Social and Economic Development Bank) and 25.17% by Logos Tecnocom (established by the researchers who have been developing the technology).
The tecnored technology uses cold pellets, or lumps, composed of fine particles of iron ore and a reducing agent (such as different types of coal), each about 50 mm across. When heated in a furnace (not a blast furnace) the reducing agent removes the oxygen from the iron ore, which is consequently transformed into pig iron. The whole process takes a mere 30 minutes – a coke-fueled blast furnace can take up to eight hours to do the same thing.
There is no need of coking or of sinterisation, as is required to produce pig iron in a blast furnace. Doing away with these processes cuts energy use as well as reducing construction costs for a new steel plant.
The furnace can use low cost energy sources for its fuel, such as coal and biomass (sugarcane bagasse, for example). The tecnored process also allows the production of pig iron from various grades and quality of iron ore, including ultra fine iron ore, which currently is dumped in tailings ponds.