Thermal decomposition of potassium chlorate in the presence of various additives is studied using thermogravimetric analysis
and differential thermal analysis. Catalytic effects of metal oxides with comparable surface areas are compared, and the catalytic
effects of a number of nonoxide additives are also studied. The nonoxide additives show catalytic activities similar to the
corresponding metal oxides. Metal cations and their electron configurations determine the catalytic activity of various compounds.
Metal cations with partially filledd shells have the highest activity, transition metal cations with completely emptyd orbitals are moderated active, and metal cations with completely filledd shells or noble gas configurations have minimum activity.
Authors:S. Pourmortazavi, S. Hajimirsadeghi, and S. Hosseini
Thermogravimetry (TG) and differential thermal analysis
(DTA) in the non-isothermal mode have been used to examine the thermal behaviour
of the micron sized aluminum (Al) powder/potassium chlorate pyrotechnic systems
in air, in relation to the behaviour of the individual constituents. The effects
of different parameters of Al powder, such as particle size and its content
in the mixtures, on their thermal property were investigated. The results
showed that, the reactivity of Al powder in air increases as the particle
size decreases. Also, it was found that neat Al with 5 m particle sizes
(Al5) has a fusion temperature of about 647C,
that for 18 m powder (Al18) is 660C. Pure
potassium chlorate has a fusion temperature around 356C and decomposes
at 472C. DTA curves for Al5/KClO3
(30:70) mixture showed a maximum peak temperature for the ignition of mixture
at 485C. Also, by increasing the particle size of Al powder, the ignition
temperature of the mixture increased. On the other hand, the oxidation temperature
increased by enhancing the Al content of the mixtures. In this particular
study, we observed that the width of reaction peak for the mixtures corresponds
to their Al contents of samples.
The thermal decomposition of -irradiated KClO3 was studied by dynamic thermogravimetry. The reaction order, activation energy, frequency factor and entropy of activation were computed using the Coats-Redfern, Freeman-Carroll and Horowitz-Metzger methods and were compared with those of the unirradiated salt. The decomposition increases with the irradiation dose. The energy of activation decreases on irradiation. The mechanism for the decomposition of unirradiated and irradiated KClO3 follows the Avrami model equation, 1-(1-)1/3, and the rate controlling process is a phase boundary reaction assuming spherical symmetry.
The determination of thallium with potassium chlorate is chosen as an example for the earlier suggested new radio-oxidimetric
titration procedure, in which phase separation is achieved by means of a strongly basic anion exchanger in the solution. Concentrations
of thallium down to 2·10−6M have been determined. Special care has to be taken for concentrations lower than 10−5M as UV radiation is a disturbing factor. Other oxidizing agents have also been tested.
The catalytic activity of a series of iron oxides on the thermal decomposition of potassium chlorate was investigated by methods of thermal analysis. Structural and electronic defects were introduced into the oxide by doping, heat treatment in different atmospheres, and irradiation withγ-rays. These induced defects changed in a systematic way the conductive properties of the iron oxides and correspondingly, their catalytic activity. The results are consistent with ann-type semiconductive behavior of the oxides.
signal friendly forces and to mark positions. These are made of an oxidizer, frequently potassiumchlorate, a fuel such as lactose, and an organic dye such as 1,4-dihydroxy anthraquinone (orange), 1-( p -tolylamino)-4-hydroxy anthraquinone (violet), 1
. Thermal decomposition of pyrotechnic mixtures containing sucrose with either potassiumchlorate or potassium perchlorate . Combust Flame. 2005 ; 141 : 322 http://dx.doi.org/10.1016/j.combustflame.2005