Asbestos Containing Material (ACM) generally refers to materials that contain chrysotile fibers. Chrystotile ((Mg,Fe)3Si2O5(OH)4)) provides heat resistance and mechanical strength to ACM but causes respiratory disorders due to its fibrous crystal structure. While safe and permanent disposal of asbestos may be a difficult environmental engineering challenge, it is essential for ensuring good public health standards. The fibrous structure of chrysotile can be altered by reacting it with CO2 to form mineral carbonates thereby rendering it safe for disposal while ensuring permanent storage of CO2 as carbonates. Direct carbonation experiments where ACM, pure chrysotile, serpentinite and olivine, reaction fluid and CO2 were stirred in a high pressure, high temperature reactor, were performed at various conditions of temperature (Tmax = 200�C) and partial pressure of CO2 (Pmax= 200 bar). The effect of various chemical additives such as oxalate, acetate etc., on enhancing ACM alteration/dissolution and formation of new phases such as carbonates was investigated. The effects of mineralogy and crystal structure on extent of carbonation were determined based on the carbonation of different magnesium silicate containing materials. One of the conventional methods of ensuring safe disposal of ACM is via heat treatment. The carbonation potential of heat treated asbestos is compared with that of untreated asbestos. Given the chemical and structural complexity of ACM, multiple analytical techniques were used to determine changes in its chemical and morphological structure. These include X-Ray Fluorescence (XRF) to determine the whole rock elemental compositions, estimation of extents of carbonation using Total Inorganic Carbon Analysis (TIC) and identification of changes in mineralogy using X-Ray Diffraction (XRD) and Electron MicroProbe Analysis (EMPA). Changes in the pore volume, particle size and morphological features were determined using BET, Particle Size Analyzer and Scanning Electron Microscopy - Energy Dispersion Spectroscopy (SEM-EDS), respectively.

CO<sub>2</sub> utilization for the treatment of asbestos containing material and its comparison to enhanced carbonation of magnesium silicate minerals

246th National Meeting (2013)

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CO2 utilization for the treatment of asbestos containing material and its comparison to enhanced carbonation of magnesium silicate minerals

CO₂ utilization for the treatment of asbestos containing material and its comparison to enhanced carbonation of magnesium silicate minerals