rejeito

Rejeito is a Portuguese term used to describe material that is discarded or rejected during a processing step. It denotes waste, residues, or by-products resulting from industrial, agricultural, or mining activities. The word is widely used in Brazil and Portugal and in other Portuguese-speaking regions. In most contexts, rejeitos are distinct from the primary product and from materials that can be recycled or reused.

In mining and mineral processing, rejeitos refer to tailings: the finely ground rock and processing fluids left after ore extraction and metal recovery. These tailings are typically stored in containment facilities such as tailings dams. Management and containment of rejeitos are governed by environmental and mining regulations due to hazards including leakage, dam failures, and groundwater contamination. Notable incidents in Brazil include the Mariana disaster in 2015 and the Brumadinho disaster in 2019.

Outside mining, the term can indicate any waste by-products produced by manufacturing, agriculture, or other industrial activities. Depending on local law, rejeitos may be classified as hazardous or non-hazardous waste and are often subject to treatment, disposal, or measures to recover secondary materials. Some rejeitos can be reprocessed to recover minerals, energy, or other value, thereby reducing environmental impact.

The concept is closely related to terms such as resíduo, rejeito industrial, and tailings.