Laboratory scale study of an industrial phosphate and thermal treatment for polluted dredged sediments

Souhila Kribi (1) , Jocelyn Ramaroson (1) , Ange Nzihou (1) , Patrick Sharrock (1) , Guy Depelsenaire (2)

1 RAPSODEE - Centre de recherche d'Albi en génie des procédés des solides divisés, de l'énergie et de l'environnement
2 Solvay

Dredged sediments are being chemically treated with phosphoric acid on an industrial scale. The effectiveness of the treatment was evaluated by performing the chemical reaction in a tubular reactor, followed by convective drying and maturation of the treated sediment at ambient temperature and finally thermal destruction of the organic matter by calcinations (500 degrees C-900 degrees C). The influence of acid concentration and calcination temperature on the specific surface area of the sediment was investigated. The stabilization of the heavy metals was evaluated by leaching tests and sequential extraction procedures. The phosphoric acid treatment is effective in reducing heavy metal mobility, a prerequisite for recycling the sediments in various construction materials.

Mots clés: Thermal treatment; Chemical treatment; Heavy metal pollution; Dredged sediments

Domaines: Sciences de l'ingénieur [physics]

Souhila Kribi, Jocelyn Ramaroson, Ange Nzihou, Patrick Sharrock, Guy Depelsenaire. Laboratory scale study of an industrial phosphate and thermal treatment for polluted dredged sediments. International Journal of Sediment Research, 2012, 27 (4), p. 538-546. ⟨10.1016/S1001-6279(13)60011-6⟩. ⟨hal-01632403⟩