Immobilization of heavy metals present in quartzite residues through incorporation in mortars with total substitution of the natural aggregate

ABSTRACT

This work aims to immobilize heavy metals present in the quartzite residues by means of the incorporation in mortars in total substitution to the natural aggregate. Two types of residues were used: quartzite sand (QS) and powder (QP). The residues were characterized by x-ray fluorescence, x-ray diffraction, and toxicity tests according to the methodology of the NBR 10005, 10006 and Toxicity Characteristic Leaching Procedure (TCLP) 1311. Then, compositions of mortar containing cement, lime and residues (QS, QP) were analyzed using technique of designing the mixture, determining the best mixture, the best type of cure (immersed or wet), and subsequently evaluated at resistance of the body of evidences after curing. The characterization of quartzite residue revealed the presence of multiple heavy metals and leached extracts in contact with the water, classifying it a Class I–Hazardous waste. Regarding the production of mortars, the results indicated that the compositions determined were able to immobilize the heavy metals present in the quartzite residues, as well as resulted in mortars with mechanical resistances higher than 2 MPa. Finally, it was shown that this technique of solubilization and stabilization of contaminants present in quartzite residues is a technologically viable and environmentally adequate alternative for the final destination of these residues.

Keywords:
ornamental rocks; immobilization of contaminants; class I waste; hazardous waste