Certain components of fuel oil ash have been tested against the refractory oxides silica and alumina. The solubility of alumina in vanadium pentoxide ranges from 1.4% at 750°C to 3.3% at 1050°C. The addition of sodium sulphate to this melt causes the solubility to rise to a slight maximum at 14 mole % Na2SO4 and from there decrease steadily to zero in the pure salt. The solubility of silica in vanadium pentoxide ranges from 1.8% at 750°C to 2.9% at 1050°C and the addition of sodium sulphate to this melt causes solubility to decrease until 18 mole % Na2SO4, from there it increases to a maximum at 58 mole % Na2SO4 and decreases to almost zero in the pure salt. The corrosion rates of alumina and silica in Na2SO4/V205 melts have been studied. The addition of sodium sulphate to vanadium pentoxide increases the corrosivity of the latter. The addition of vanadium pentoxide to sodium sulphate increases the corrosivity of the latter. At compositions between 30 and 70 mole % Na2SO4 in V205 corrosion rates are similar for both refractories. The diffusion coefficients for silica and alumina in these melts have been evaluated and for both systems a maximum occurs at 30 mole % Na2SO4. The kinetics of the reaction between sodium sulphate and vanadium pentoxide to produce vanadates have been investigated. Activation energies vary between 20 and 32 kcal/mole. Attempts were made to hot press firebrick to theoretical density. Results show that this should be possible at 1350°C under 1.15 kg/mm2. The mechanism is viscous flow, above 1100°C with an energy of activation of 55 kcal/mole.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:623025 |
| Date | January 1968 |
| Creators | Gravette, Nigel Charles |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/15828 |
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