The Effect of the Reaction pH on Properties of Lead(II) Azide.

Lead(II) azide is an initiating explosive; even a small amount can trigger an explosion caused by simple external stimuli, such as sparks, flames, friction or pinpricks, and is able to initiate the explosive reaction of rock-crushing explosives. Due to the fact that this initiating explosive triggers further reactions, the effect of priming detonators depends on the properties of its material. Its sensitivity is associated with the size of its crystals. For instance, it is used for mining detonators in the form of fine crystals. The quality of the crystals is also correlated to the safety of the production process, i.e., the crystals should be round-shaped rather than needle-like since breaking it would inevitably trigger an explosion. The process of lead(II) azide production on an industrial scale is based on the reaction of lead(II) nitrate with sodium azide with the presence of dextrin, which determines the desired shape of the crystals. The reaction pH affects the number of sediment particles formed in a periodical reactor. Changing the pH from 6.5 to 7.5 leads to the rapid growth of crystal particles.

Fluctuations of the elemental composition in the layers of mineral deposits formed on the elements of biogas engines.

The aim of the research was to compare the chemical composition and morphology of the surface of the backsheet growing on the metallic and surface substrate growing already on the prepared mineral substrate. Moreover the aim of this study was also to analyze the dispersion of chemical elements on the cross-sections of deposits formed on parts of landfill biogas-driven engines. The chemical composition of extreme layers of mineral deposits extracted from the engine piston and their cross-sections from four pistons and one head was examined by SEM-EDS. The bottom side showed a much smaller heterogeneity of the topography of the surface than the topside. The chemical composition of the deposit bottom side it primarily S (41%), Si (34%) and Al (17%). In the case of the top side, the dominated of Ca (52%) with a relatively high share of S (32%) and Si (14%). The presence of P and Mg it was also found, but only on the bottom side, and the share of Fe and Zn only on the top side. In the case of cross-sections, Ca, S and Si were the dominant elements. In general, there were higher Si participations in the zone of the bottom layer with a downward trend to the top sheet. The mass shares of S and Ca were lower in the zone of the bottom layer with the upward trend to the top sheet, also undergoing fluctuation.

Destruction of halogen-containing pesticides by means of detonation combustion.

Pesticides that contain a halogen functional group have been destructed by means of detonative combustion. The following compounds were examined: (1) atrazine-2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine-herbicide; (2) bromophos-O,4-bromo-2,5-dichlorophenyl O,O-dimethyl phosphorothioate-insecticide; (3) chloridazon-5-amino-4-chloro-2-phenylopyridazin-3(2H)-one-herbicide; (4) linuron-3-(3,4-dichlorophenyl)-1-metoxy-1-methylurea-herbicide; (5) metoxychlor-1,1,1-trichloro-2,2-bis(4-metoxyphenyl)ethane-insecticide and acaricide; and (6) trichlorfon-dimethyl 2,2,2-trichloro-1-hydroxyethylphosphonate-insecticide. Explosive material has been produced on the basis of ammonium nitrate, which served as an oxidizer while the pesticides were used as fuels. Composition of the explosive was adjusted in such a way as to respect thermodynamic parameters. Detonative decomposition of the mixtures has been carried out in shot-holes pre-drilled in soil. Efficiency of the pesticide decomposition has been examined with gas chromatography in order to determine pesticides residues in the environment. It was found that for some, the amount of pesticides in some compounds in the analyzed samples after decomposition was below the determination threshold of the applied method.

Neutralization of 4,6-dinitro-o-cresol waste pesticide by means of detonative combustion.

Neutralization of 4,6-dinitro-o-cresol, of which the best-before date had expired and which could not be used any longer, was carried out by means of the detonative combustion method. The pesticide comprises two nitro groups and is called DNOC. Composition of the applied explosive was designed on the basis of porous ammonium nitrate as an oxidizer and the pesticide as fuel. The thermodynamic parameters of such an explosive were estimated, and then three series of experiments with detonative decomposition of the material under a shield of sand were performed: in a steel chamber, in shot-holes in soil, and in shot-holes in a quarry. The efficiency of the pesticide decomposition was examined by determination of the residual remainder of the pesticide in the environment by means of gas chromatography. It was stated that pesticide content in the analyzed samples was below the determination threshold of the applied method. Biological tests with plants were carried out as well. Suggestion was made that the energy being produced during detonative combustion can be utilized for useful work, e.g. rock mining in a quarry.