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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.

The clay brick is one of the oldest building materials, and as the use of waste in the bricks can reduce clay consummation and the environmental burden due to the accumulation of waste, the present study was chosen, the addition of mineral and organic waste to the clay brick. The added value of this work, which was carried out within the Institute of Building Materials at VGTU, is that the mixture studied is very special, because the raw materials used are: − Yellow Clay (C) from Fez which is used only in the field of pottery; − Pyrrhotite Ash (PA) which is a mineral waste produced during the manufacture of sulphuric acid from the roasting of pyrrhotite ore. This waste is stored in the open air since 1982 and until now it doesn't have any specific use; − Cedar Sawdust (S) is an organic waste regenerate by the artisanal sector from Fez. The bricks’ technological properties depended on the amount of ashes used. So, adding 5% S to the mixture (20% PA – 80% C) gives rise to a new material that is light, porous with a natural brick red colour. Most importantly, this material exhibits mechanical strength according to the standards of a terracotta brick.

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