Environmental study and valorization of an ashy waste: case of pyrrhotite ash

Abstract

Pyrrhotite ash is an industrial waste which is currently stored in large quantities in a large area in southwest of Morocco. The literature review revealed that this waste has been used by some cement industries and has not been the subject of any environmental study or valuation in another area. This work focuses on the environmental study of pyrrhotite ash. This study consists of a dynamic test with renewing lixiviate more particularly the leaching tank test. The protocol used is extracted from the Dutch standard NEN 7345 with modification of the volume of water used and the number of extraction. Quantitative analysis by ICP has shown that pyrrhotite ash releases heavy metals in aqueous medium. However, the concentration of these is very low compared to the limits estimated by the Dutch standard adapted to the Moroccan hydrological context (MBMD), this result encouraged us to find a way to valorise this waste and to make it a raw material for the manufacture of terracotta bricks made of clay.