Stabilization of Residues Obtained from the Treatment of Laboratory Waste: Part 2—Transformation of Plasma Vitrified Slag into Composites

Abstract

ABSTRACT The Sustainable Environment Research Center of National Cheng Kung University in Taiwan has set up a treatment plant to dispose of laboratory waste. In the treatment process, the residue from the incineration system and the physical and chemical system is vitrified by a plasma melting system. Part 1 of this study described the treatment path of metals during vitrification. In Part 2, plasma vitrified slag is reused by using a molding technology. Unsaturated polyester resin and glass fiber were used as the molding material and additive, respectively, in the molding process. With an appropriate mixing ratio of unsaturated polyester resin, glass fiber, and slag, the physical properties of composites improved, and the ultimate tensile strength reached 17.6 MPa. However, an excess amount of slag reduced the strength and even retarded the production of composites. Differential thermal analysis and the water bathing test results show that the composite decomposed at 80 °C and that it vaporized at 187 °C. Although the unsaturated polyester resin decomposed, the metal encapsulated in the slag did not leach out. The results show that the reuse of slag using molding technology should be taken into consideration. IMPLICATIONS The reuse of vitrified slag is an important issue for the vitrification of hazardous materials. A molding technology that mixes glass fiber, slag, and unsaturated polyester resin is used to make a composite in this study. With appropriate addition of slag and glass fiber, the physical properties of unsaturated polyester resin improved. In addition, the composites are stable in general environmental conditions. The reuse of slag in the form of composites as building material or decoration should be taken into consideration.