Vale has inaugurated its new dry pilot plant for processing iron ore in Minas Gerais, Brazil, as it continues to reduce its use of water in ore and waste processing.
The Brazilian technology, known as FDMS (Fines Dry Magnetic Separation), is unique and has been developed by New Steel – a company Vale acquired in late 2018.
The pilot plant, which cost $3 million, is the first step towards the construction of an industrial plant that will have a production capacity of 1.5 Mt/y. The investment in this project is near $100 million, with the commercial plant start-up scheduled for 2022, as the company announced back in February.
Vale estimates that, in 2024, 1% of all the company’s production will use this technology, whose patent is already recognised in 59 countries.
President of New Steel, Ivan Montenegro, said: “NS-03 is a semi-industrial plant to carry out tests on a pilot scale with different types of ore, allowing the definition of operational parameters for commercial-scale projects.”
Installed at Vale’s Ferrous Technology Center, in Nova Lima, the pilot plant is the second to start operating. Between 2015 and 2017, a unit operated at the Fábrica mine, also in Minas Gerais. The results allowed Vale to see the potential of the FDMS technology, it said, ultimately leading to Vale taking over New Steel.
The new pilot unit will be able to concentrate 30 t/h of ore using dry magnetic separation technology equipped with rare earth magnets.
Vale’s Executive Director of Ferrous, Marcello Spinelli, said New Steel puts the company at the “forefront” of investments in ore processing technology.
“We will continue to seek solutions that increase the safety of our operations,” he added.
With New Steel and its dry process technology, Vale estimates that, in 2024, 70% of production will come from dry or natural moisture processing, without adding water to the process and without using tailings dams. Today, the company produces 60% of iron ore using natural moisture processing.
By 2024, from the production using wet processing (30%), 16% will have filtered and dry-stacked tailings, with only 14% continuing to use the conventional method with wet concentration and tailings disposal in dams or deactivated extraction sites.
This transition will see Vale invest $1.8 billion in filtering and dry stacking in the coming years. The first units to use the technique will be Vargem Grande complex (in Nova Lima), Pico mine (in Itabirito), Cauê and Conceição mines (in Itabira), and Brucutu mine (in São Gonçalo do Rio Abaixo).
New Steel’s technology can deliver a concentrate with iron content up to 68% Fe from poor ore with content up to 40% Fe, depending on its chemical and mineralogical composition, according to Vale. Currently, this concentrate is produced by flotation, which uses water. In flotation, the tailings are usually disposed of in dams, but, with the dry concentration technology developed by New Steel, the tailings will be stacked.
Vale is studying methods to use these filtered cakes as raw materials for the civil construction industry, in addition to other initiatives, such as co-products.