Decomposition of Chrysotile Asbestos by Fluorosulfonic Acid

The effect of a fluorosulfonic acid (FSO{sub 3}H) aqueous solution on decomposing the chrysotile asbestos fibers was investigated by using FT-IR, XRD, and XPS. From the equilibrium of FSO{sub 3}H in an aqueous medium (FSO{sub 3}H + H{sub 2}O = HF + H{sub 2}SO{sub 4}), the resulting H{sub 2}SO{sub 4} had a strong affinity for the external Mg(OH){sub 2} layers in the tubular, scroll-like chrysotile structure. This acid-base reaction led to the precipitation and lixiviation of MgSO{sub 4}{center_dot}H{sub 2}O, MgO, and Mg{sup 2+} ion. Once the breakage of the outer Mg(OH){sub 2} layers occurred, HF readily diffused into the inner silicious layers and then reacted with silicates, converting them into SiO{sub 2} hydrate and H{sub 2}SiF{sub 6}, while the ionic reaction between lixiviated Mg{sup 2+} and F{sup {minus}} resulted in precipitating MgF{sub 2}, thereby destroying the fibrous nature of the asbestos. An optimum combination of HF and H{sub 2}SO{sub 4} contributed significantly to enhancing the rate of conversion of asbestos into nonfibrous materials in a short treatment time without any physical agitation.