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Land Contamination
Published in Daniel T. Rogers, Environmental Compliance Handbook, 2023
Acids or bases are only toxic if they are strong, meaning they are of relatively low or high pH. Exposure to strong acids and bases causes respiratory irritation and burning and skin burns. Significant exposure may cause severe burns and even death (USEPA 2021c). Currently, adequate information is not available to evaluate the potential carcinogenic effects of common acids and bases (USEPA 2021c). Ammonia is a common basic chemical widely used as a household cleaning agent and in many industrial applications (ATSDR 2018f). Ammonia is present naturally throughout the environment in air, soil, and water. Exposure to high levels of ammonia may cause lung, skin, and throat irritation. Some people with asthma may react more negatively to the inhalation of ammonia (ATSDR 2018f). Hydrochloric acid (also referred to as hydrogen chloride) is a common acid widely used in industry as a cleaning agent, in the manufacturing of PVC, in making steel, and in making leather. Hydrochloric acid is also present in humans and other organisms as a gastric acid and sometimes exists as an acid mist. This mist may cause skin and lung irritation, and skin burns can occur if you are exposed to a highly concentrated mist for a prolonged period (ATSDR 2002b).
Applied Chemistry and Physics
Published in Robert A. Burke, Applied Chemistry and Physics, 2020
Most acids are produced by dissolving a gas or a liquid in water. For example, hydrochloric acid is derived from dissolving hydrogen chloride gas in water. All acids contain hydrogen. This hydrogen is an ion (H+) and can be measured by using the pH scale (Figure 3.138), which, in simple terms, measures the hydrogen ion concentration of a solution. Acids as a group have high hydrogen ion concentration. Bases have very low hydrogen ion concentrations and high hydroxyl (OH−) concentrations. The strength or weakness of an acid or base is the amount of hydrogen ions or hydroxyl ions that are produced as the acid or base is produced. If the hydrogen ion concentration in an acid is high, then the acid is a strong acid. If the hydroxyl concentration is high, then it is a strong base. In both cases, there is almost total ionization of the material dissolved in water to make the strong acid and base. For example, hydrochloric acid is a strong acid with a pH of 1.1; almost all of the hydrogen chloride gas is ionized in the water. If the hydrogen ion concentration is low, then the acid is a weak acid. Acetic acid is a weak acid with a pH of 3; only about 2% ionization has occurred in producing the compound.
Contamination
Published in Daniel T. Rogers, Urban Watersheds, 2020
Hydrochloric acid (also referred to as hydrogen chloride) is a common acid widely used in industry as a cleaning agent, in the manufacturing of PVC, in making steel, and making leather. Hydrochloric acid is also present in humans and other organisms as a gastric acid (ATSDR 2002b), and sometimes exists as an acid mist. This mist may cause skin and lung irritation, and skin burns can occur if you are exposed to a highly concentrated mist for a prolonged period (ATSDR 2002b).
Halogenation of used aluminum matrix test reactor fuel – a bench-scale demonstration with surrogate materials
Published in Journal of Nuclear Science and Technology, 2022
Steven D. Herrmann, Haiyan Zhao, Meng Shi, Matthew M. Jones, Michael N. Patterson
While not related to the EMT of used ATR fuel, researchers from the European Union (EU) used aluminum as a cathode in a uranium electrorefiner to exploit the thermodynamic stability and associated co-deposition of not only uranium but also transuranium metals onto an aluminum metal cathode in a chloride electrolyte [17–20]. The use of an aluminum cathode to form actinide-aluminum alloys in a uranium electrorefiner has an advantage in an improved separation of actinides from lanthanides over other reactive cathodes, such as a liquid cadmium cathode. However, an additional step is required to separate and recover actinides from the actinide-aluminum alloy, which the same EU researchers demonstrated using chlorination. They conducted experiments with uranium-aluminum alloys that were exposed to pure chlorine gas [17–19] and hydrogen chloride gas [20]. Specifically, they conducted several experiments with the chlorination of gram and sub-gram quantities of pulverized UAl3/UAl2 with varying extents of excess pure chlorine gas in a range of 150–170°C, yielding a UCl4/UCl3 and AlCl3 product per the following reaction mechanisms.
Extraction of Scandium and Iron from Red Mud
Published in Mineral Processing and Extractive Metallurgy Review, 2022
Ding Wei, Xiao Jun-Hui, Peng Yang, Shen Si-Yue, Chen Tao, Zou Kai, Wang Zhen
The course of segregation roasting involves the chlorination reaction of iron oxide and scandium and the subsequent reduction reaction. During the heating process, the chlorinating agent reacts with water vapor and silica in the ore to generate hydrogen chloride. Then, reaction of hydrogen chloride with metal oxides (Fe2O3) and adsorbed scandium to generate the respective metal chloride (FeCl3, ScCl3). Finally, the metal chloride (FeCl3, ScCl3) is reduced to metal on the surface of coke and the HCl is regenerated. It is a remarkable fact is that metal scandium will be converted into scandium oxide in the air, but scandium in a separate form favorable for acid leaching extraction of scandium from magnetic separation tailings. The iron reduction mechanism and scandium conversion during the roasting process are shown below (Dean 1999; Halmann, Epstein and Steinfeld 2012; Xiao et al. 2020b; Xiao and Zhang 2020c).
Catalytic Effect of Added Fe2O3 Amount on Thermal Decomposition Behaviors and Burning Characteristics of Ammonium Nitrate/Ammonium Perchlorate Propellants
Published in Combustion Science and Technology, 2020
Ammonium nitrate (AN)-based composite propellants are popular for application in gas generators, side thrusters, and military devices as they are eco-friendly, less hazardous, and generate a minimal amount of smoke. However, these propellants face several major problems, such as low burning rates, poor ignitability, and low energy. On the other hand, ammonium perchlorate (AP)-based propellants are used most widely because of their excellent burning characteristics. However, they have some serious drawbacks, such as the release of hydrogen chloride, chlorine, and chlorine oxides, which cause atmospheric pollution. AN/AP propellants are prepared with AN and AP as an oxidizer, and therefore, the drawbacks of AN are mitigated by the advantages of AP and vice versa. The burning characteristics of AN/AP-based propellants have been reported (Doi and Kuwahara, 2015; Kohga and Togo, 2018; Kohga et al., 2008; Sinditskii et al., 2008; Takahashi et al., 2013).