Stabilization of NaCl-containing cuttings wastes in cement concrete by in situ formed mineral phases.
Disposal of NaCl-containing cuttings is a major environmental concern due to the high solubility of chlorides. The present work aims at reducing the solubility of chloride by encapsulation in low permeability matrix as well as lowering its solubility by trapping into low-solubility phases. Both the studied materials were cuttings from an oil-based mud in oil drillings containing about 50% of halite, and cuttings in water-based mud from gas drilling containing 90% of halite. A reduction in the amount of dissolved salt from 41 to 19% according to normalized leaching tests was obtained by addition of potassium ortho-phosphate in the mortar formula of oil-based cuttings, while the aluminium dihydrogeno-phosphate is even more efficient for the stabilization of water-based cuttings with a NaCl content of 90%. Addition of ortho-phosphate leads to form a continuous and weakly soluble network in the cement matrix, which reduces the release of salt. The formed mineralogical phases were apatite and hydrocalumite. These phases encapsulate the salt grains within a network, thus lowering its interaction with water or/and trap chloride into low-solubility phases. The tested approaches allow to develop a confinement process of NaCl-containing waste of various compositions that can be applied to wastes, whatever the salt content and the nature of the drilling fluids (water or oil).
Filippov
Lev
L
Laboratoire Environnement et Minéralurgie, Nancy Université-UMR 7569 CNRS, F-54501 Vandoeuvre-lès-Nancy, France. lev.filippov@ensg.inpl-nancy.fr
Thomas
Fabien
F
Filippova
Inna
I
Yvon
Jacques
J
Morillon-Jeanmaire
Anne
A
D002623:Chemistry Techniques, Analytical; D003252:Construction Materials; D004777:Environment; D007220:Industrial Waste; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning / Q000379:methods; D010710:Phosphates / Q000737:chemistry; D017680:Potassium Compounds / Q000737:chemistry; D012037:Refuse Disposal; D012965:Sodium Chloride / Q000737:chemistry*; D012995:Solubility; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*; D014961:X-Ray Diffraction
D007220:Industrial Waste; D010710:Phosphates; D017680:Potassium Compounds; D012965:Sodium Chloride; C013216:potassium phosphate