Following extensive research that began more than 35 years ago, Tecnored Desenvolvimento Tecnológico S.A., a Vale company, in partnership with Brazil’s development bank, BNDES, and Logos Tecnocom, have started up the first pig iron demonstration plant that does not use traditional blast furnace methods, in Pindamonhangaba, São Paulo state. Pig iron is a fundamental element in steel production. The innovation enables higher productivity, lower emissions of CO2 and particulate matter, the flexible use of raw materials, and a reduction of up to 30% in the cost of steel production.
The technology, called Tecnored, may help to extend the lifespan of Vale’s mines and reduce their environmental impact, as it enables pig iron to be produced from iron ore of different grades and quality, and even ultrafine iron ore, which is currently deposited in tailings ponds. “By using iron ore fines, we can reduce the need to open up new areas for tailings ponds, which require environmental licenses to be created,” said Pedro Gutemberg, global director of basic materials marketing. Vale.
According to Gutemberg, although the results are promising, Tecnored is still at the first stage of development. The next steps are to ensure operational stability and pursue economic feasibility. “This start-up has encouraged us to move ahead in our research, as the tests show that the technology is technically feasible.”
The new technology’s secret lies in the use of cold pellets that measure 50 mm across and made up of lumps of fine particles of iron ore and a reducing product, such as different types of coal. The reducing agent removes oxygen from the iron ore, which is transformed into pig iron when heated in the furnace. Low-cost fuels such as coal or biomass (sustainably grown timber, sugarcane bagasse, etc.) can be used to supply the process with energy.
By using the cold pellets, the new Tecnored technology eliminates the need to use coke and sinterization facilities—indispensable parts of existing steel mills—and significantly reduces construction costs. This is because both coking (the process of preparing coal for use in the blast furnace) and sinterization (the thermal process of agglomerating ore fines) require heavy investment and large areas for their plants.
By eliminating coking and sinterization, it is possible to cut energy use, and consequently emissions of particulate matter and carbon dioxide, as well as raising the productivity of the whole process. Iron oxide reduction using Tecnored takes place in just 30 minutes, while in coke-fueled blast furnaces, for example, reduction may require up to eight hours.
The company’s technicians forecast that by using Tecnored, an industrial plant could produce 85% less particulate matter if compared with a traditional steel mill. Nitrogen oxide (NO) emissions may fall even more drastically, by up to 95%. Although it is not a greenhouse gas, NO indirectly contributes to global warming by reducing plants' photosynthesis capabilities, and it is also harmful to people's respiratory system. Tecnored can also cut CO2 emissions by up to 5%.
Another innovation lies in the furnace’s size and versatile design. While in traditional steelmaking, the blast furnace is between 20 and 30 m in height, the Tecnored plant’s furnace reaches no higher than 5 m. “Besides being compact, the furnace has the added benefit of being made up of modules, which allows its size and production potential to be raised in line with objectives,” said Gutemberg,
According to Gutemberg, the innovation is a great opportunity to produce pig iron at more competitive prices, and this may attract more international partners to the steel projects that Vale is developing in Brazil. “It’s also worth emphasizing that this is a genuinely Brazilian technology, developed with Vale’s complete support,” he said. Vale owns 43.04% of Tecnored’s shares; BNDESPar, BNDES’ investment arm, owns 31.79%; and Logos Tecnocom, which represents the researchers who developed the technology, has 25.17%. Seven patents related to the new technology have so far been filed, covering 35 countries.
The demonstration plant, whose production capacity is 75,000 metric tons per year (mt/y), was started up on September 12. Since it joined the venture in 2009, Vale has invested around R$130 million of the total of approximately R$250 million spent so far to develop it. The company is committed to building an industrial plant capable of producing 300,000 mt/y—10% of the nominal capacity of a traditional blast furnace.