Physics
Scientific paper
Aug 2005
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005gecoa..69.4073d&link_type=abstract
Geochimica et Cosmochimica Acta, Volume 69, Issue 16, p. 4073-4083.
Physics
1
Scientific paper
The effect of lattice disorder and mineral surface area on the reactivity of finely ground fluorite was studied on ball-milled powders. Structural information was provided by X-ray whole powder pattern modeling (WPPM). The mean size of coherent scattering domains decreases with milling time from 70 nm to ˜20 nm, whereas the density of lattice defects increases with both time and intensity of milling treatment, from 4 × 1015 m-2 to 24 × 1015 m-2. High resolution transmission electron microscopy (HRTEM) of ground fluorite grains shows several line defects and a general tendency of nanometric crystalline domains to agglomerate in larger grains. Solution chemistry was investigated using batch reactors with free drift of solution saturation state with respect to fluorite. Total surface area was measured by the Brunaver, Emmet and Teller (BET) method, and dissolution rates were measured at pH = 2 (HCl) and T = 295 K. In far from equilibrium conditions, dissolution rates normalized by BET area do not increase with the dislocation density. In near-equilibrium condition, however, measured stationary ionic product clearly increases with both time and intensity of milling treatment. Thermodynamic predictions of the solubility constant indicate negligible or little effect of total surface area. Consequently, the observed increase in the stationary ionic product can be related to the increasing lattice defect content. This confirms the significant role of dislocation outcrops on mineral dissolution in close to equilibrium conditions.
Biddau Riccardo
D'Incau Mirco
de Giudici Giovanni
Leoni Matteo
Scardi Paolo
No associations
LandOfFree
Dissolution of nanocrystalline fluorite powders: An investigation by XRD and solution chemistry does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Dissolution of nanocrystalline fluorite powders: An investigation by XRD and solution chemistry, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dissolution of nanocrystalline fluorite powders: An investigation by XRD and solution chemistry will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-955659