title: Carbon dioxide sequestration using NaHSO4and NaOH: A dissolution and carbonation optimisation study.
abstract: The use of NaHSO4to leach out Mg fromlizardite-rich serpentinite (in form of MgSO4) and the carbonation of CO2(captured in form of Na2CO3using NaOH) to form MgCO3and Na2SO4was investigated. Unlike ammonium sulphate, sodium sulphate can be separated via precipitation during the recycling step avoiding energy intensive evaporation process required in NH4-based processes. To determine the effectiveness of the NaHSO4/NaOH process when applied to lizardite, the optimisation of the dissolution and carbonation steps were performed using a UK lizardite-rich serpentine. Temperature, solid/liquid ratio, particle size, concentration and molar ratio were evaluated. An optimal dissolution efficiency of 69.6% was achieved over 3 h at 100 °C using 1.4 M sodium bisulphate and 50 g/l serpentine with particle size 75-150 μm. An optimal carbonation efficiency of 95.4% was achieved over 30 min at 90 °C and 1:1 magnesium:sodium carbonate molar ratio using non-synthesised solution. The CO2sequestration capacity was 223.6 g carbon dioxide/kg serpentine (66.4% in terms of Mg bonded to hydromagnesite), which is comparable with those obtained using ammonium based processes. Therefore, lizardite-rich serpentinites represent a valuable resource for the NaHSO4/NaOH based pH swing mineralisation process.
authors.affiliation: Centre for Innovation in Carbon Capture and Storage (CICCS), Institute of Mechanical, Process and Energy Engineering (IMPEE), School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK. Electronic address: a.sanna@hw.ac.uk.
authors.forename: Aimaro
authors.initials: A
authors.lastname: Sanna
authors.affiliation: Centre for Innovation in Carbon Capture and Storage (CICCS), Institute of Mechanical, Process and Energy Engineering (IMPEE), School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
authors.forename: Luc
authors.initials: L
authors.lastname: Steel
authors.affiliation: Centre for Innovation in Carbon Capture and Storage (CICCS), Institute of Mechanical, Process and Energy Engineering (IMPEE), School of Engineering & Physical Sciences, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
authors.forename: M Mercedes
authors.initials: MM
authors.lastname: Maroto-Valer
mesh_terms: D001194:Asbestos; D002245:Carbon Dioxide / Q000737:chemistry; D057965:Carbon Sequestration; D002254:Carbonates / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D010316:Particle Size; D059027:Recycling; D012972:Sodium Hydroxide / Q000737:chemistry*; D012995:Solubility; D013431:Sulfates / Q000737:chemistry*; D013696:Temperature; D006113:United Kingdom
chemical_list: D002254:Carbonates; D013431:Sulfates; C012036:sodium sulfate; C046240:lizardite; D001194:Asbestos; D002245:Carbon Dioxide; C005686:sodium carbonate; D012972:Sodium Hydroxide
keywords: CCS; CO(2) fixation; Clean energy; Mineral carbonation; Sodium salts