DECOMPOSITION OF CHRYSOTILE ASBESTOS BY FLUOROSULFONIC ACID

The effect of a fluorosulfonic acid (FSO3H) aqueous solution on decomp osing the chrysotile asbestos fibers was investigated by using FT-IR, XRD, and XPS. From the equilibrium of FSO3H in an aqueous medium (FSO3 H + H2O = HF + H2SO4), the resulting H2SO4 had a strong affinity for t he external Mg(OH)(2) layers in the tubular, scroll-like chrysotile st ructure. This acid-base reaction led to the precipitation and lixiviat ion of MgSO4 . H2O, MgO, and Mg2+ ion. Once the breakage of the outer Mg(OH)(2) layers occurred, HF readily diffused into the inner siliciou s layers and then reacted with silicates, converting them into SiO2 hy drate and H2SiF6, while the ionic reaction between lixiviated Mg2+ and F- resulted in precipitating MgF2, thereby destroying the fibrous nat ure of the asbestos. An optimum combination of HF and H2SO4 contribute d significantly to enhancing the rate of conversion of asbestos into n onfibrous materials in a short treatment time without any physical agi tation.