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Components of Energetic Compositions
Published in John A. Conkling, Christopher J. Mocella, Chemistry of Pyrotechnics, 2019
John A. Conkling, Christopher J. Mocella
Other oxidizers—including barium chromate (BaCrO4), lead chromate (PbCrO4), sodium nitrate (NaNO3), lead dioxide (PbO2), lead tetroxide (Pb3O4), bismuth oxide (Bi2O3), copper oxide (CuO), and barium peroxide (BaO2)—will also be encountered in subsequent chapters. Several novel or non-legacy oxidizers are being looked at as “green pyrotechnics” alternatives to perchlorates and barium-based compounds. One such example is potassium ferrate—K2FeO4—which decomposes to red iron oxide—Fe2O3—upon combustion but is susceptible to acidic conditions and will generally have a much lower burning temperature than potassium perchlorate it is intended to replace (Wilharm, Chin and Pliskin 2014).
Synthesis of Solids
Published in Elaine A. Moore, Lesley E. Smart, Solid State Chemistry, 2020
Elaine A. Moore, Lesley E. Smart
Ignition is sometimes initiated by heating the whole volume evenly, and self-ignition can sometimes be achieved by ball milling. The method is now used commercially in Russia, Spain, and Korea because it is fast, economical, and gives high-purity products. The ferrite BaFe12O19 has been used in magnetic stripes on credit cards (Chapter 9). Thermal ignition of a mixture of BaO2, Fe2O3, Cr2O3, and Fe produces a Cr-substituted ferrite, BaFe12-xCrxO19. The exothermic reaction here is the oxidation of the metallic iron. Barium peroxide, BaO2, decomposes during the reaction and provides a source of oxygen. For x = 2, the reaction is BaO2(s)+2.5Fe2O3(s)+Cr2O3(s)+5Fe(s)+3.5O2(g)=BaFe10Cr2O19(s)
Preparatory Processes Before Printing
Published in Asim Kumar Roy Choudhury, Principles of Textile Printing, 2023
Bleaching with peroxides seems to have passed through three phases in its history, the first being the early use of barium peroxide and the solutions of hydrogen peroxide which could be made from it. This came to an end around 1912, when sodium peroxide became available in commercial quantities. Since about 1927, concentrated solutions of hydrogen peroxide have been manufactured from various routes. It is, in fact, the only oxidative bleaching agent for wool and silk, but is also safe for all textile fibers – hence the name “universal bleacher”.
Effects of CaCl2, Al(OH)3, And NH4H2PO4 on the Explosion Intensity of Pulverized Coal
Published in Combustion Science and Technology, 2023
Xiaofeng Ren, Jiangshi Zhang, Qi Zhang, Yongtun Li, Linquan Tong, Longhao Sun
Coal was obtained from the Buertai Coal Mine in Ordos, Inner Mongolia, China. Coal powders were screened through a 200-mesh sieve (particle size<75 μm). Zirconium powder (particle size<48 μm) was purchased from Shanghai Changbei Nano Materials Technology Co., Ltd., China. Barium nitrate (particle size<48 μm) was purchased from Chongqing Bemengsi Chemical Co., Ltd., China, whereas barium peroxide (particle size<48 μm) was purchased from Chongqing Huaqi Fine Chemical Co., Ltd., China. Zirconium powder, barium nitrate, and barium peroxide are materials used to make chemical igniters. The industrial characteristics of the coal samples were tested using an industrial analyzer (GF-A6) as per the ISO (2013). The test results are listed in Table 1. Then, the coal-dust explosion index was calculated using Equation (1) (Zhang et al. 2022):
Thermodynamic model of metallothermic smelting of ferromolybdenum
Published in Mineral Processing and Extractive Metallurgy, 2019
A very exothermic ignition mixture, consisting of aluminium powder and a strong oxidant such as sodium peroxide Na2O2 (Braithwaite and Haber 1994), potassium chlorate KClO3 (Suri and Gupta 1997) or barium peroxide Ba2O2 (Habashi 1997), is used to initiate the reaction. The smelting period varies from 30 to 60 min and, due to the high temperature and high volatility of MoO3, up to 1% of the molybdenum in the charge reports as dust (Habashi 1997). A relationship was found between reaction temperature and smelting time by Gasik et al. (2009) by varying the amount of aluminium in batch sizes of 1–3 t at the Tchelyabinsk Electrometallurgy Plant, as shown on Figure 4. This data, however, must be regarded as tentative due to the difficulty of measuring such high temperatures and accessing the reacting charge to take a measurement.
Montmorillonite Powder and Its Hydroxyl Modified Powder Experimental Study on the Inhibition of Lycopodium Powder Explosion
Published in Combustion Science and Technology, 2023
Qiyan Wu, Xiangbao Meng, Yansong Zhang, Yang Wu, Wenjiao Dai, Li Liu, Lei Shi, Tong Wang
Before the experiment, the lycopodium powder, Mt powder and O-Mt powder were put into a vacuum environment at 40°C and dried for 24 hours. During the experiment, the ignition tip was connected to the ignition electrode at the center of the explosion tank through a wire, and the ignition tip was prepared by zirconium powder, barium peroxide and barium nitrate in the ratio of 4:3:3. Experiment using a total mass of 0.48 g ignition tip, the total energy of 2000J, the experiment measured the tip can produce about 0.02MPa maximum explosion pressure. Then, the pre-weighed powder sample was put into the dust storage chamber, and the storage tank with a volume of 0.6 L was pressurized to 2MPa by a high-pressure gas cylinder, and the explosion tank was evacuated to 0.06MPa by a vacuum pump to ensure that the explosion tank pressure was 1 atmosphere at the time of dust ignition. Finally, the computer control system (activating the data logger, opening the solenoid valve, and dispersing the dust sample through the high-pressure air into the 20 L explosion tank via a diffuser, and igniting the dust cloud by the ignition tip after a delay of 60 ms) was used to collect the pressure data by computer (Liu et al. 2022, 2022). After each experiment, the post-explosion products were collected and the explosion tank was thoroughly cleaned to avoid interference with the next experimental data. At the end of each explosion experiment, the inner wall of the tank, the inner wall of the sealing cover and the umbrella-shaped powder spray are cleaned with a wool brush and a dry towel, and the residual samples after the explosion are sucked out with a vacuum cleaner. This process is repeated many times until the experimental device is completely cleaned.