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The Use of Small Particle Catalysts in Pursuit of Green and Sustainable Chemistry
Published in Ahindra Nag, Greener Synthesis of Organic Compounds, Drugs and Natural Products, 2022
As a primary process in hydrometallurgy, leaching transfers desired metals from a mineral or ore containing metals to an aqueous solution provides a means to concentrate the metals. The term lixiviant is used in hydrometallurgy to describe a liquid medium that can selectively extract the desired metal from an ore or metal mixture. It has been discovered that lixiviant compositions of dihalogen/S,S-ligands, N,N′-dimethylperhydrodiazepine-2,3-dithione (Me2dazdt) in the presence of iodine (I2) for recovery of precious and noble metals from a non-ferrous metal fraction derived from shredded waste electronic equipment (Scheme 9.22).242
Effect of Metal Complexation on the Solubility of Rare Earth Compounds
Published in Abhilash, Ata Akcil, Critical and Rare Earth Elements, 2019
The introduction of hydrometallurgy to extractive metallurgy dates back many centuries. It is believed that about 1,000 years ago, the effective combination of leaching with cementation for copper was practiced. The main thrust of hydrometallurgy can be found in leaching of minerals bearing valued metals in either acidic solutions or alkaline media. Hydrometallurgical extraction is a low-temperature process that occurs in water and is now favored over pyrometallurgical process. Especially suitable for low-grade ores, the popularity of hydrometallurgy is evident by the fact that selective recovery of various metals is possible. It frequently produces sulfur or sulfate as undesirable products, whereas sulfur dioxide gas is an undesirable product in pyrometallurgical operation.
Recovery of Metal from Electronic Waste for Sustainable Development (through Microbial Leaching/Bioprocesses)
Published in V. Sivasubramanian, Bioprocess Engineering for a Green Environment, 2018
Shankar Nalinakshan, Aneesh Vasudevan, J. Kanimozhi, V. Sivasubramanian
Hydrometallurgy, that is, the leaching and cementation process, was first mentioned in 1907 in the Serbian mine Bor when 200 tons of copper were produced. In general, hydrometallurgy is a process that uses aqueous solutions to extract metals from ores. The most significant step in the hydrometallurgical process is leaching, which involves dissolving the metals into the aqueous solution or a suitable solvent (acids or halides are used as leaching agents) followed by various purification and concentration processes such as distillation, precipitation, adsorption, solvent extraction, and the cementation electrometallurgical process. At times, the electrometallurgical process may be carried out directly on the material without pretreatment.
The effect of ultrasound on the sulfuric acid leaching of uranium by use of MnO2 as a oxidant
Published in Geosystem Engineering, 2021
Kyeong Woo Chung, Ho-Sung Yoon, Chul-Joo Kim, Ho-SeoK Jeon
Nuclear power generation has been increased world-wide, giving rise to the much consumption of uranium as a raw material. It has resulted in the progressive depletion of high-grade uranium reserves. Low-grade ore of uranium has attracted much attention, and a novel hydrometallurgical process has been studied for its development (Li et al., 2020; Mirjalili & Roshani, 2007). In the hydrometallurgy of ore, leaching is a core process that determines valuable elements’ degree of recovery. Therefore, economic leaching technology is required to develop low-grade uranium ore.
Factorial design for process optimization and generation of kinetic data for yttrium and europium leaching
Published in Mineral Processing and Extractive Metallurgy, 2021
Amit Anand, Randhir Singh, Malay Kumar Ghosh, Kali Sanjay
The chemical forms in which REMs are present in phosphors limit the application of pyro or electrometallurgy and make hydrometallurgy the most suitable route for extracting these metals (Tunsu et al. 2015). In hydrometallurgy, leaching is the first step which involves selective dissolution of targeted metals into aqueous phase. Several researchers have carried out leaching studies of Y and Eu from phosphor. Optimum leaching conditions suggested by some of these studies are listed in Table 2.
Hydrometallurgical processes for heavy metals recovery from industrial sludges
Published in Critical Reviews in Environmental Science and Technology, 2022
Viraj Gunarathne, Anushka Upamali Rajapaksha, Meththika Vithanage, Daniel S. Alessi, Rangabhashiyam Selvasembian, Mu. Naushad, Siming You, Patryk Oleszczuk, Yong Sik Ok
Hydrometallurgy can be defined as a metal recovery method used to obtain metals from ores and waste materials using aqueous media by combining water, oxygen, and other chemical reagents with or without the use of a pressurized environment. Hydrometallurgical metal recovery is typically performed in three main stages: metal dissolution, concentration and purification, and metal recovery (Gupta, 2006) (Figure 4).