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Air Purification
Published in O. Nelson Gary, Gas Mixtures, 2018
Compressed gases may also contain acid gases (hydrogen cyanide, sulfur dioxide, chlorine, and hydrogen chloride), carbon monoxide, and carbon dioxide. Acid gases and carbon dioxide can be removed with soda lime, a mixture of calcium and sodium hydroxides. Soda lime with various moisture contents is available in sizes of 4 to 14 mesh, in either the regular or the indicating form, and can absorb up to 25% of its own weight in carbon dioxide. The rate at which acid gases are absorbed depends on the condition of the lime. As the lime becomes spent, a thin film of calcium carbonate covers the surface of the soda-lime particles and cannot be removed by regeneration. Acid gases can be removed by several types of treated carbons. The usual impregnation materials are metal salts of copper and chrome. These materials are also commonly used in air-purifying, respiratory-protective cartridges and canisters.
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Published in James P. Lodge, Methods of Air Sampling and Analysis, 2017
Compressed gases may also contain acid gases, carbon monoxide, and carbon dioxide. The acid gases are those that produce hydrogen ions either by direct dissociation or by hydrolysis and include hydrogen cyanide, hydrogen chloride, and sulfur dioxide. Both acid gases and carbon dioxide can be filtered out by soda lime, a mixture of calcium and sodium hydroxides. Soda lime with various moisture contents is available in sizes from 4 to 14 mesh, in either the regular or the indicating form, and can absorb up to 25% of its weight of carbon dioxide. The rate at which acid gases are absorbed by soda lime depends on the condition of the lime. As the lime becomes spent, a thin film of calcium carbonate covers the surface of the soda lime particles and cannot be removed by regeneration.
Effect of glass powder on the rheological and mechanical properties of slag-based mechanochemical activation geopolymer grout
Published in European Journal of Environmental and Civil Engineering, 2022
Mukhtar Hamid Abed, Israa Sabbar Abbas, Hanifi Canakci
Slag and glass powder (GP) were used in this research to produce a mechanochemical geopolymer. The slag is obtained from the iron and steel industry (Iskenderun Iron and Steel Plant in Hatay province, Turkey), and the GP is obtained from green soda-lime bottles collected primarily from shops in Gaziantep, Turkey. The waste green soda-lime bottles were first washed with tap water to remove labels from the exterior of the glass and then cleaned inside to remove impurities. The waste green soda-lime bottles were naturally dried in the laboratory for 24 hours and grounded to powder using a Los Angeles abrasion machine. Finally, the glass powder passed the No. 35 sieve with a particle size less than 0.5 mm and was adapted for the mechanochemical activation process. Also, CEM I-42.5R Portland cement in accordance with ASTM C150 was used to produce Portland cement grout for comparison purposes. The combination of NaOH and sodium silicate as alkaline activators was chosen in this research. Sodium hydroxide pellets with a purity of 98% were locally obtained. The ratio of sodium metasilicate powder (Na2SiO3-Penta) to sodium hydroxide is 0.5. Table 1 summarises the physicochemical characteristics of the OPC, precursor components (slag and GP) and Na2SiO3.
Growth of β-NaGaO2 thin films using ultrasonic spray pyrolysis
Published in Journal of Asian Ceramic Societies, 2022
Issei Suzuki, Shunichi Suzuki, Tatsuya Watanabe, Masao Kita, Takahisa Omata
Sodium is one of the most attractive elements for use in materials because it is nontoxic, environment friendly, and abundant. Although elemental sodium and simple sodium-containing compounds such as sodium oxide cannot be used directly because they are highly reactive to moisture and carbon dioxide and are unstable in the atmosphere, they can be used as constituents in materials including soda-lime silicate glass for windows [1–3]. In addition to these conventional applications, various sodium-containing complex oxides have recently attracted attention for application as functional material in thermoelectric devices [4–6], photocatalysts [7–9], sensors [10–12], and rechargeable batteries [13–18]. The usage of sodium for future material development will continue to increase because of its above-mentioned desirable properties.
Exploration of boron removal from molten silicon by introducing oxygen resources into ammonia blowing treatment
Published in Canadian Metallurgical Quarterly, 2019
Zhiyuan Chen, Yuliu You, Kazuki Morita
Boron-doped silicon was prepared with solar-grade silicon (purity: ∼7 N), to which known concentration of boron (Soekawa Chemicals Co. in Japan, purity: ≥ 99.9 mass%) was added. For this study, 2 g of pure silicon and 163 or 146 ppmw of boron were placed in a high purity graphite crucible and pre-melted at 1450°C in pure argon atmosphere for 2 h. The reactant gas used to remove B was diluted ammonia, which is prepared by diluting the Ar + 3 vol.-% ammonia gas (Sumitomo Seika Chemicals Company Ltd. in Japan) with high purity argon gas (Jyotou Gas Co. in Japan). The reactant gas passed through soda lime, CaO and Mg(ClO4)2 to remove CO2 and water, respectively, before introduced into the reaction furnace. The gas feeding rate was set at 300 mL min−1. Before the reaction, the B-doped silicon was held in a pure argon atmosphere at the reaction temperature for 20 min. In the experiments of combined gas blowing and slagging, pre-melted slag with CaO:SiO2 = 0.75 in mass ratio was added into the graphite crucible (inner diameter 13 mm) on the top of the silicon. The mass ratio of slag:Si was 1.25. Reaction continues for 6 h at 1500°C. In the experiments of the moist gas blowing treatment, no slag was added, and the reaction time was controlled as 2 h at 1500°C. The samples were quenched and picked out after the reaction. The boron content in the samples was detected using an inductively coupled plasma atomic-emission spectroscopy (ICP-AES, SII SPS7700 or SPS 3500, Hitachi High-Tech Science Corporation in Japan).