Microwave-assisted acid treatment for the mineral transformation of chrysotile as an alternative for asbestos waste management

Abstract

In this work, the efect of microwaveassisted acid treatments on the morphological and crystallochemical characteristics of chrysotile fbers is investigated. A low concentration of nitric acid (0.2 N) is used to remove Mg2+-species located in the octahedral sheet of its structure, thereby causing a crystallo-chemical change forming a skeleton of noncrystalline amorphous silica. This skeleton maintains an elongated morphology but characterized by rounded -not sharp-edges and porous surfaces whose physical resistance under stress is reduced when compared with the initial fbers of chrysotile, favoring a lower pathogenicity of the fbers. Thus, microwaveassisted acid treatment rise as a low-cost, fast and efective option in avoiding the dangerousness associated with asbestos waste management.