Ammonium nitrate (AN) is one of the main nitrogen fertilizers used in fertilization programs. However, AN has some serious
disadvantages — being well soluble in water hardly 50% of the N-species contained are assimilated by plants. The second disadvantage
of AN is associated with its explosive properties. The aim of this paper was to clarify the influence of different lime-containing
substances — mainly Estonian limestone and dolomite — as internal additives on thermal behaviour of AN.
Commercial fertilizer grade AN was under investigation. The amount of additives used was 5, 10 or 20 mass%, or calculated
on the mole ratio of AN/(CaO, MgO)=2:1 in the blends. Experiments were carried out under dynamic heating condition up to 900°C
(10°C min−1) in a stream of dry air or N2 by using Setaram Labsys 2000 equipment coupled to Fourier transform infrared spectrometer (FTIR).
The results of analyses of the gaseous compounds evolved at thermal treatment of neat AN indicated some differences in the
decomposition of AN in air or in N2. At the thermal treatment of AN’s blends with CaCO3, MgCO3, limestone and dolomite samples the decomposition of AN proceeds through a completely different mechanism — depending on
the origin and the content of additives, partially or completely, through the formation of Mg(NO3)2 and Ca(NO3)2.
Authors:I. Alexandrova, K. Gjurova, and G. Iordanov
The thermal stabilities of PVC/poly(MMA-co-DVB) polymer systems and membranes prepared by the paste method were investigated.
The thermoanalytical curves were used to determine the main thermal stage of the decompositions. It was found that the thermal
properties of the polymer systems were affected by the divinylbenzene content. A membrane based on the PVC/poly(MMA-co-DVB)
system with 5 mass% DVB displays thermal stability up to 210C.
Authors:F. Chehimi-Moumen, D. Ben Hassen-Chehimi, M. Ferid, and M. Trabelsi-Ayadi
The preparation of a new acid lanthanide diphosphate is reported. The acid praseodymium diphosphate, obtained as a trihydrate salt, is investigated by chemical analysis, X-ray powder diffraction and IR spectroscopy. The study of the thermal behavior of HPrP2O7·3H2O shows that its dehydration begins at 367 K. A scheme of its decomposition is proposed.
Infrared spectra of a series of anhydrous (Rb, Cs) and hydrated (Na, K, Ca, Sr, Ba, Pb, Ag, Tl) salts of the complex anion VO(C3H2O4)2]2− were recorded and briefly discussed. The thermal behaviour of these compounds, as well as that of the corresponding diprotonated ethylenediamine cation, were investigated by TG- and DTA-methods in N2-atmosphere and complemented with studies carried out in crucible furnaces in air. Pyrolysis intermediates and residues were characterized by IR spectroscopy and overall stoichiometries for the degradation processes were proposed. In most cases orthovanadate/VO2 mixtures were obtained as final residues in N2, whereas the corresponding divanadates were produced in air.
Authors:J. M. Amigó, J. Garcia-González, and C. Miravitlles
The thermal behaviour of [CoCO3(NH3)4]2SO4 · 3H2O was studied using X-ray diffraction diagrams, DTA, TG and heating at constant temperatures for different periods of time. The X-ray study was made in order to characterize with the powder diagrams the phases obtained and to follow the reactions of the complex when heated in air up to 800‡. A parallel infrared spectral study was also made. The results obtained by the various experimental methods were compared with the theoretical weight losses.
Authors:Corina Duda-Seiman, T. Vlase, Gabriela Vlase, Rodica Cinca, Mariana Anghel, and N. Doca
screening drug-excipient interactions. The use of hyphenated techniques allows the identification of evolved volatile compounds resulted by thermodegradation process and an accurate determination of the differences in drug’s thermalbehavior induced by
The thermal behaviour ofγ-sulfur, monoclinicα-Se, S6Se2, S5Se3, S4Se4 and S3Se5, has been studied by hot-stage microscopy and differential scanning calorimetry. X-ray diffraction results show that S6Se2 and S5Se3 are isostructural with Sγ, but S4Se4 and S3Se5 are isostructural with monoclinicα-Se. The melting of Sγ, is accompanied by rapid crystallization of Sβ, which often occurs almost simultaneously with melting. The melting of S6Se2, S5Se3, S4S4 and S3Se5 is irreversible as the compounds decompose on melting. For monoclinicα-Se no phase transformation to monoclinicβ Se was observed at 110–120°, but it changes to hexagonalα-Se when the temperature is over 120°.
Authors:Liang Xue, Feng-Qi Zhao, Xiao-Ling Xing, Zhi-Ming Zhou, Kai Wang, Hong-Xu Gao, Jian-Hua Yi, and Rong-Zu Hu
thermodynamic of 3,4,5-triamino-1,2,4-triazole dinitramide is a basic task in the content of thermal process. The thermalbehavior of materials may be determined in a short time using thermal analysis techniques such as DSC, TG-DTG, but more intensive and
The optimum conditions for extraction of ion-associated complexes (IAC) formed from the tetrazolium salt-tetrazolium violet and Sb(V) in hydrochloric acid medium have been studied. An isotope of antimony (125Sb) was used for determination of the recovery factor (R%) and distribution ratio (DSb). The thermal behavior of the antimony complex with tetrazole violet was studied using differential thermal and thermogravimetric analysis.