Browsing by Author "Bultosa, Geremew"

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    Kinetics of the Thermal Decomposition of Cadmium Carbonate (CdCO3)
    (University of Dar es Salaam, 1993) Bultosa, Geremew
    Kinetics of the thermal decomposition of cadmium carbonate have been established by thermogravimetric method. Cadmium carbonate was prepared from cadmium chloride, ammonium carbonate and ammonia. Chemical analysis has been conducted on prepared sample product. The result of chemical analysis in in a good agreement with theoretical and with the one directly calculated from thermogram r-ray powder diffraction pattern obtained for sample cadmium carbonate and for corresponding oxide were consistent with standard diffraction pattern. The inflated spectral obtained for sample cadmium carbonate were typical of divalent metal carbonate vibrations. All these analysis show that the prepared product is of analytical acceptable purity. Kinetic studies were conducted on this product by both isothermal and non-isothermal methods under the purging with dry nitrogen gas. Under these conditions the decomposition kinetics were best described by two –dimensional reaction of phase bounder’s movement cylindrical symmetry.) rate controlling step. Activation of energy of 125.53/ml and frequency factory (inz) of 16.754 have been determinate by isothermal method after stimulating rate constants for nine isothermal temperatures (400, 390,380,370,360,350,340,320 and 320) Non-isothermal kinetic studies were conducted at the beating rates of 2,4,6,8 10 k/nin, activation energy and frequency factor determined for these heating rates were between 153,888-146 KJ/nol and 20.356-18.879 respectively, the value being large for low heating rate. Finally the effect of sample mass on kinetic parameters have been studied by using masses of 10.574,20.715, 30.530, 40.141, 50.368 mg. the values of both activation energy and frequency factor decreases as the sample mass increases.