Dataset for "Influence of clay minerals and associated minerals in alkali activation of soils"

Technical details and requirements:

For particle size distribution (Fig. 1): The particle size distribution was measured by a combination of wet-sieving, to measure particle grading from 2 mm – 63 μm, and hydrometer testing, to measure particle grading < 63 μm by using the principle of Stokes’ Law to measure particle size by the time taken for particles to fall out of suspension in water. For plastic limit (Fig. 2): Atterberg plastic limit measurements were taken for montmorillonite and illite over a range of sodium hydroxide solution concentrations, based on BS 1377-2:1990. From these data a best fit line was plotted to extrapolate the volume of solution required to reach plastic limit consistency for a given concentration. A correction was made to exclude the mass of the sodium hydroxide from the solids mass in the plastic limit calculations. For XRD (Figs. 4, 5, 6, 7, A2): Powder X-ray diffraction (PXRD) analysis was done to identify phases with a Bruker D8 Advance instrument using monochromatic CuKalpha1 L3 (λ = 1.540598 Å) X-radiation and a Vantec superspeed detector. A step size of 0.016° (2θ) and step duration of 0.3 seconds were used. Phase identification was done using Bruker EVA software. Patterns were corrected for sample height shift by calibrating to the most intense quartz reflection (101) at 26.6° (2θ). For FTIR (Figs. 11, 12, 13): Fourier Transform Infrared Spectroscopy (FTIR) was done to characterise molecular bonding, using a Perkin-Elmer Frontier with a diamond Attenuated Total Reflectance (ATR) head. Spectra were collected over a range of 4000-600 cm⁻¹ using a resolution of 4cm⁻¹ and 5 scans per spectrum. Corrections were made for ATR and background using Perkin-Elmer Spectrum software. For TGA/MAS (Figs. 14, 15, 16): Thermogravimetric analysis (TGA) was done to characterise thermal behaviour, using a Setaram Setsys Evolution TGA over a range of 30 to 1000 °C at a heating rate of 10 °C/minute. An air atmosphere was used, with a flow rate of 20 ml/minute. A connected mass spectrometer was used (Pfeiffer Omni) to identify whether evolved gas species contained OH, H2O, CO or CO2.