Synthesis of Nano-Sized Silicon Oxide, Iron Oxide and Carbonates from Chrysotile Asbestos

The objectives of this study were to investigate the physicochemical dissolution of chrysotile asbestos and to synthesize nano-sized materials and carbonate minerals from the asbestos via acid dissolution and pH changes. Chrysotile asbestos powder was dissolved in 3 different acids, HCl, HThe objectives of this study were to investigate the physicochemical dissolution of chrysotile asbestos and to synthesize nano-sized materials and carbonate minerals from the asbestos via acid dissolution and pH changes. Chrysotile asbestos powder was dissolved in 3 different acids, HCl, H₂SO₄, and HNO₃, and the solutions were then titrated using NH₄OH and reacted with CO₂. The residual material and precipitates were examined with XRD and TEM-EDS. ICP-AES analysis was also used to investigate the chemical makeup of the solution. The concentration of Mg in the solution was about 1,280 mg/L. The chrysotile became noncrystalline silica after acid treatment (pH = 0). At pH 8.6 and 9.5, the precipitates were amorphous iron oxide and nesquehonite [Mg(HCO3)(OH)·2(H₂O)] after reaction with CO₂. The particle size of the precipitates ranged from 2 to 500 nm. These results indicate that dissolution of chrysotile asbestos using HCl, H₂SO4, and HNO3 can chemically alter chrysotile fibers. Also, the dissolved materials can be used as precursors for other materials such as silica, iron oxide, and carbonates. This process may be useful for the synthesis of silica and iron oxides and for mineral carbonation for carbon sequestration. SO4, and HNO₃, and the solutions were then titrated using NH4OH and reacted with CO₂. The residual material and precipitates were examined with XRD and TEM-EDS. ICP-AES analysis was also used to investigate the chemical makeup of the solution. The concentration of Mg in the solution was about 1,280 mg/L. The chrysotile became noncrystalline silica after acid treatment (pH = 0). At pH 8.6 and 9.5, the precipitates were amorphous iron oxide and nesquehonite [Mg(HCO₃)(OH)·2(H₂O)] after reaction with CO₂. The particle size of the precipitates ranged from 2 to 500 nm. These results indicate that dissolution of chrysotile asbestos using HCl, H₂SO₄, and HNO3 can chemically alter chrysotile fibers. Also, the dissolved materials can be used as precursors for other materials such as silica, iron oxide, and carbonates. This process may be useful for the synthesis of silica and iron oxides and for mineral carbonation for carbon sequestration.