Decomposition of asbestos by a supernatant used for immobilization of heavy metals in fly ash

• Published in: Journal of material cycles and waste management Vol. 18; no. 3; pp. 483 - 492
• Main Authors: Tabata, Masaaki, Shono, Akifumi, Ghaffar, Abdul
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.07.2016; Springer Nature B.V
• Subjects: Analysis; Asbestos; Calcium hydroxide; Chromium; Civil Engineering; Construction; Decomposition; Diffraction; Engineering; Environmental Management; Fly ash; Hazardous materials; Hazardous wastes; Heavy metals; Immobilization; Industrial wastes; Leachates; Methods; Special Feature: Original Article; Studies; Sulfur; Tremolite; Waste disposal; Waste Management/Waste Technology; Waste materials; X-ray diffraction; Fly ash; Decomposition; Asbestos; Heavy metals; Supernatant
• ISSN: 1438-4957; 1611-8227
• DOI: 10.1007/s10163-016-0491-2

A supernatant solution, obtained after immobilization of heavy metals involved in fly ashes by a solution of sulfur and calcium hydroxide, was re-used for immobilization of heavy metals and decomposition of asbestos in construction materials. Asbestos was decomposed to more than 99.9 % by mixing it with the supernatant in a ball mill at room temperature. The decomposition of asbestos was confirmed by X-ray diffraction (XRD), a phase contrast microscope after staining the asbestos with solutions of different diffractive indexes and a scanning electron microscope. XRD indicated complete disappearance of specific main peaks of asbestos: chrysotile, crocidolite, amosite and tremolite. Heavy metals such as chromium(VI) and lead(II) in fly ashes were completely immobilized by the supernatant. It is the first time that a solution obtained after the treatment of wasted fly ash is recycled for decomposition of hazardous waste materials such as asbestos.