Thermal reduction of barium sulphate with carbon monoxide: a thermogravimetric study

The kinetic parameters of the reduction of barium sulphate to barium sulphide using carbon monoxide fractions of 2.4–9.6% and temperatures of 850–1000 °C, using an isothermal thermogravimetric method, were obtained. This reaction has shown to be temperature and carbon monoxide concentration dependent. By variation in temperature, at constant CO fractions, an average activation energy of 149 (±10) kJ/mol was observed. By changing the CO fraction at constant temperature, it is suggested that the reduction reaction is first order in CO. An overall reaction rate equation is propose

A kinetic expression for the pyrolytic decomposition of polyterafluoroethylene

Despite the fact that the thermal decomposition of polytetrafluoroethylene has been extensively studied over the past six decades, some inconsistencies regarding the kinetic parameters, e.g. the order of the reaction, remain. Representative kinetic data are essential for practical purposes such as reactor design and scaling. In general the literature data refer to homogeneous bulk heating, whereas the case of the non-homogeneous heating of a single particle has not received attention. Data (reaction rate and pre-exponential factor) applicable to this latter case were experimentally determined from isothermal thermogravimetric analyses of the depolymerisation reaction of PTFE. The kinetic data obtained on coarse granules (800–1000 μm) are reported here. The rate law is consistent with a shrinking particle kinetic model, with chemical kinetics controlling phase-boundary movement. The mass loss rate is directly proportional to surface area. A rate law applicable to this case, and useable for geometries of arbitrary shape, is derive

Improved procedures for separating crystals from the melt: final report. Pt.2: final reports of the individual contractors

The influence of the crystallization pilameters on the shape and size of ecaprolactam formed in supercooled melts was investigated in the absence and in the presence of impurities