Characterization and processing of an haematitic stockpile for pellet feed production

Abstract

A current concern related to low-grade stockpiles is to develop processing routes for the production of high-grade pellet feed. The stockpiles possess complex mineralogical composition of hematite and undesirable minerals bearers of aluminium and sulphur that require the development of a processing route aiming the production of high iron grade material with acceptable grades of contaminants. With an average iron grade of 48.6%, the material of the haematitic stockpiles was produced at the end of a beneficiation process consisting of crushing and screening. After grinding to achieve P80 106 μm, satisfactory concentration was achieved by magnetic separation (WHIMS) in three or four stages, depending on the desired product quality. Such flexibility led to the proposal of two possible processing routes. When the scavenger stage product is incorporated into the pellet feed, although the iron grade diminishes, the mass recovery increases by approximately 5%. The investigation proved that it is possible to produce pellet feed from the haematitic stockpiles with the processing routes tested. However, further grinding is required in order to adequate the material granulometry for its application as pellet feed.