title: Olivine dissolution from Indian dunite in saline water.
abstract: The rate and mechanism of olivine dissolution was studied using naturally weathered dunite FO98.21(Mg1.884Fe0.391SiO4) from an Indian source, that also contains serpentine mineral lizardite. A series of batch dissolution experiments were carried out to check the influence of temperature (30-75∘C), initial dunite concentration (0.5 and 20 g/L), and salinity (0-35 g/L NaCl) under fixed head space CO2pressure (P[Formula: see text] = 1 barg) on dunite dissolution. Dissolved Mg, Si, and Fe concentrations were determined by inductive coupled plasma atomic emission spectroscopy. End-product solids were characterized by scanning electron microscopy and X-ray diffraction. Initially, rates of dissolution of Si and Mg were observed to be in stoichiometric proportion. After 8 h, the dissolution rate was observed to decline. At the end of the experiment (504 h), an amorphous silica-rich layer was observed over the dunite surface. This results in decay of the dissolution rate. The operating conditions (i.e., salinity, temperature, and mineral loading) affect the dissolution kinetics in a very complex manner because of which the observed experimental trends do not exhibit a direct trend.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology - Bombay, Powai, Mumbai, 400076, India.
authors.forename: Amit Kumar
authors.initials: AK
authors.lastname: Agrawal
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology - Bombay, Powai, Mumbai, 400076, India. mehra@iitb.ac.in.
authors.forename: Anurag
authors.initials: A
authors.lastname: Mehra
mesh_terms: D002245:Carbon Dioxide / Q000737:chemistry; D058085:Iron Compounds / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry; D054712:Salinity; D017640:Silicates / Q000737:chemistry*; D012965:Sodium Chloride; D012995:Solubility; D013696:Temperature; D014961:X-Ray Diffraction
chemical_list: D058085:Iron Compounds; D017616:Magnesium Compounds; D008903:Minerals; D017640:Silicates; D002245:Carbon Dioxide; D012965:Sodium Chloride; C034475:olivine
keywords: Carbon dioxide capture; Indian dunite; Olivine dissolution; Salinity