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Contacts

Matriz
Av Amintas Barros, 3400
CTC Torre Business - Sala 1804
Lagoa Nova, Natal
Rio Grande do Norte, Brasil
CEP: 59075-810
Telefone: +55 (84) 3344-7100
Fax:         +55 (84) 3344-7105


Mina do Bonito - Jucurutu
Sítio Bonito, S/N
Zona Rural, Jucurutu
Rio Grande do Norte, Brasil
CEP: 59330-000

Iron ore Carving and Refining Process

The carving process is performed with excavation equipment – bulldozers and mechanic shovels, which carry the product (run of mine) in large size trucks that will feed the refining plant. The carving operations include the removal and storage of the ground for future rehabilitation of the mining location.

The ore originating from the mine (run of mine) is fed in a grinder whence it moves on to a screen that separates the larger particles and sends them for crushing. Crushing is carried out in two or three stages, with jaw (primary), conical (secondary or tertiary) or impact (tertiary) crushers. Such crushers operate in a closed circuit with screens, resulting in a product smaller than 32mm.

This product is then classified into fractions of different sizes: the product smaller than 32mm and larger than 6.3mm is called granulated or lump, and can be loaded directly into the reduction furnaces for production of metallic iron; the product smaller than 6.3mm and larger than 1.0mm is called sinter feed, before it’s loaded into the reduction furnaces. If it’s an impure product, it is submitted to concentration (magnetic or gravimetric) and only the magnetic or heavy fractions are recovered. The non-magnetic or light fractions are discarded as reject.

Products smaller than 1.0mm and larger than 0.15mm may have two destinies. They can become a part of the sinter feed, after being concentrated by means similar to those above, or they can be grinded for the production of the fourth product, pellet feed. Pellet feed is the material smaller than 0.15mm and generally larger than 0.01mm, since an extremely fine fraction, smaller than 0.01mm, constitutes the mud which is separated and forms reject. Such pellet feed is concentrated by means of fluctuation, a process that takes advantage of the hydrophobic properties of certain reagents that adhere to the surface of the quartz, leading it to follow air bubbles generated in  a piece of equipment called a flotation cell. In this equipment, the hematite particles (iron oxide) sink, and form a concentrate.