Browsing by Author "Ingram, Malcolm D."

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Acid–base properties of molten oxides and metallurgical slags
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (06), 1978) Duffy, John A.; Ingram, Malcolm D.; Sommerville, Iain D.
    The application of the Lux–Flood concept to acid–base reactions in oxide systems is discussed in the light of spectroscopic information concerning the “state” of oxide ions. In slag systems (e.g. molten silicates) it is possible for the basicity to be expressed in terms of electron donor power as an optical basicity (Λ), and not in terms of the activity of O2– ions. CaO is chosen as the reference oxide of unit basicity; Λ-values are either measured spectroscopically or calculated from the equation Λ=ΣXiΛi, where Xi and Λi are equivalent fractions and (assigned) basicity values for slag components. The optical basicity scale provides a means for comparing acid–base indicators in oxide melts, rather analogous to the use of the Hammett acidity function (HO) in strong protonic acids and is applicable to multicomponent systems. Possible applications of optical basicity to metallurgy are exemplified by reference to the sulphide capacities (Cs) of iron and steelmaking slags. Data for ≈ 130 blast furnace slags show a good correlation between log Cs and Λ, even for slags which do not contain SiO2. Evidence is supplied that optical basicities can also be derived from ESCA measurements; Λ-values obtained in this way might be useful in assessing the properties of steel making slags.
  • No Thumbnail Available
    Item
    Diffusion of Trace Ions in Glass Forming Molten Nitrates
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (1-6), 1974) Ingram, Malcolm D.; Lewis, Geoffrey G.
    Diffusion coefficients of the ions Ag+, Cl– and Br– in molten KNO3+ Ca(NO3)2 of molar ratio 62 : 38 have been determined by chronopotentiometry. In the range 400–550 K the results fit a modified Fulcher equation, Di=AiT½ exp [(–ki)/(T–T0)], where T0= 316 K. The values of the Fulcher coefficients, ki, are all close to that previously found for electrical conductivity. The measured values of DBr– depart from the Fulcher equation below 400 K, and there are signs of a return to Arrhenius behaviour. It is suggested that in the Fulcher region the transport mechanism for diffusion and conductivity involves cooperative translations of both cations and anions, but that at lower temperatures there is a transition to a “glass-like” transport mechanism in which only certain ions are regarded as mobile.