Recovery of magnetic iron contained in beach sands

Abstract

Preconcentration involves discarding a fraction of the feed prior to mineral processing so that it contains the smallest or least amount of mineral of interest; this reduces the mass to be processed in subsequent operations, lowering capital and operating costs. This study seeks to evaluate the possibility of obtaining a benefit from beach sand samples through gravitational separation tests to separate the dense minerals, followed by a low-intensity grinding and magnetic separation stage to concentrate the magnetite. The analyzed sample presents opaque minerals such as magnetite, ilmenite, rutile, hematite, titanite, and titano-magnetite. Chemical analysis reveals that the sand contains 62.3% SiO₂, 8.2% CaO, 8.6% Fe, 1.8% K₂O, 2.0% TiO₂, and 0.23% P₂O₅. The treatment applied to the sand allowed the recovery of 39.3% of magnetic iron, with a grade of 56.6%, and 23.4% of TiO₂, with a grade of 8.1%. The results indicate that discarding more than 64.7% of the gangue is possible. This study demonstrates that physical separation processes allow the remediation of contaminated sand, delivering a profitable product.