2. Materials and methods
2.1. Pulverised fuel ash
Class F fly ash (ASTM C618-92a) was obtained from the 2000 MW coal fired power station at West Burton, UK (EDF Energy). Table 1 gives representative chemical composition data. The loss on ignition
was determined by calcining 2 g pre-dried samples at 925 ◦C for 1 h.Particle size distribution data shown in Fig. 1 were obtained by laser diffraction using aMalvernMastersizer (Malvern Instruments,UK). This indicates that the as-received fly ash had an average particle size (d50) of approximately 33 m. X-ray diffraction (XRD) was completed on as-received fly ash that was ground to less than 150 m (Philips VW 1700 Series), using K radiation at an accelerating voltage of 40 kV and a current of 40 mA. The corresponding XRD data is given in Fig. 2 and this shows that quartz (SiO2) and mullite (3Al2O3·2SiO2) with some haematite (Fe2O3) are the major crystalline phases present.
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