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Sustainability Issues in the Engineering and Construction Industry
Published in J.K. Yates, Daniel Castro-Lacouture, Sustainability in Engineering Design and Construction, 2018
J.K. Yates, Daniel Castro-Lacouture
Half the rare earth minerals are extracted from mining operations in China because the toxic nature of the extraction process results in strip-scarred and toxic reservoirs containing radioactive wastewater. Due to environmental regulations in the United States, many of the rare earth mines closed down in the 1970s. In 2010, one of the rare earth mines was reopened in the United States at a cost of $500 million to clean up the mine and additional costs were incurred to recycle the wastewater produced at the mine to generate hydrochloric acid and sodium hydroxide, which is required during the separation process for rare earth minerals. New processes have been developed for reducing water consumption at the mine to 10% of the amount of water required when the mine was operating in the 1970s. Additional rare earth mines might also be reopened in the future in the United States that use newer, more sustainable extraction processes.
Rare Earths
Published in S. Komar Kawatra, Advanced Coal Preparation and Beyond, 2020
REEs are a set of 17 elements on the periodic table covering the 15 lanthanides plus scandium and yttrium. These elements play an essential role in many technologies, including but not limited to catalysts, permanent magnets, lamp phosphors, and rechargeable batteries. As such the REEs are becoming increasingly important as a strategic resource. With China currently exporting more than 90% of the global REE output and its increasingly tight export regulations, the rest of the world faces a risk to their ability to access REEs (Binnemans et al., 2013). While the United States has significant reserves of rare earth minerals, it is necessary to develop efficient processing technologies to extract these elements at low cost.
Wave energy converter systems – status and perspectives
Published in Dezhi Ning, Boyin Ding, Modelling and Optimization of Wave Energy Converters, 2022
Robert Mayon, Dezhi Ning, Boyin Ding, Nataliia Y. Sergiienko
Notwithstanding the challenges to the commercialisation of wave energy outlined above, harvesting energy from ocean waves has many advantages over other forms of renewable energy [132]. In contrast with both wind and solar power, it is a relatively constant source of energy with comparatively little temporal variation. Solar power plants cannot operate at night-time, and during overcast days they do not operate efficiently. Wind power faces the same problems with regards to temporal variability in wind speeds. Solar power-plants require large tracts of land to install photovoltaic arrays, often up to 4 hectares per MW [811]. Onshore wind turbine arrays also require vast areas of land. Modern onshore wind turbines have an average capacity of about 2 MW and a rotor diameter of about 100 meters. The turbines are usually spaced at a minimum of 6 rotor diameters from each other in the streamwise direction and 4 to 5 rotor diameters in the cross-wind direction [795]. This necessitates an extensive land area for the installation of a wind turbine array. Photovoltaic arrays require the mining of rare earth minerals, which has a significant, detrimental environmental impact. Furthermore, construction of solar power plants and onshore wind farms are often opposed by local residents, as they can have a negative visual (and sometimes auditory in the case of wind farms) impact on the landscape and its ecology, a phenomenon referred to as the “not in my backyard (NIMBY)” effect [832]. Additionally, whilst offshore wind turbines generate significantly more power than their onshore counterparts, they are significantly more expensive to install and maintain. Most of these listed disadvantages associated with other forms of renewable energy are relatively minor for WEC devices.
Collector Chemistry for Bastnaesite Flotation – Recent Developments
Published in Mineral Processing and Extractive Metallurgy Review, 2019
Weiping Liu, Xuming Wang, Jan D. Miller
The rare earth minerals are mainly concentrated by gravity, magnetic, electrostatic, and froth flotation separation techniques. The typical gravity separation of rare earth minerals is found in the beneficiation of monazite from heavy mineral sands which is based on the differences in specific gravities (Gupta and Krishnamurthy 1992). Furthermore, gravity separation equipment, such as shaking tables, spiral concentrators, and conical separators, is used together with froth flotation in many rare earth separation plants in China. Magnetic separation is a common unit process to remove highly magnetic invaluable minerals, such as Fe-bearing minerals, or to concentrate paramagnetic rare earth minerals, such as monazite or xenotime (Gupta and Krishnamurthy 1992). Electrostatic separation is mainly used to separate monazite and xenotime from invaluable minerals with similar specific magnetic and gravity properties and to concentrate ultrafine coal particles containing rare earth elements (Higashiyama and Asano 1998). Froth flotation, which is the main separation technology for bastnaesite, as reviewed in this paper, is commonly used in Bayan Obo, China, and Mountain Pass, United States (Liu et al. 2016).
Investigation on the Sulfadiazine Schiff Base Adsorption Ability of Y(III) Ions from Nitrate Solutions, Kinetics, and Thermodynamic Studies
Published in Solvent Extraction and Ion Exchange, 2023
Amal E. Mubark, Samar E. Abd-El Razek, Ahmed A. Eliwa, Sabreen M. El-Gamasy
There are 169 kinds of rare earth minerals discovered, and more than 250 kinds of minerals contain these rare earth elements. But based on the latest industrial production technology, there are about 50 kinds of rare earth minerals with industrial and commercial value, and only about 10 of them are used to produce rare earth products, such as Bastnaesite, Monazite, Xenotime, Fergusonite, Ion-absorbed-type rare earth ores, Gadolinite, Euxenite, and Allanite, and only the first five rare earth minerals are the main minerals in the rare earth industry.[8]
Safe, clean, proliferation resistant and cost-effective Thorium-based Molten Salt Reactors for sustainable development
Published in International Journal of Sustainable Energy, 2022
Finally, thorium is not commercially used as nuclear fuel. It is left as radioactive waste after mining for rare earth minerals and – metals, which become environmental and social issues within the resource-rich countries (Kamei 2011). It is important to note that thorium has very low radioactivity. As (Martin 2009) writes; ‘It’s only slightly radioactive; you can carry a lump of it in your pocket without harm’. Nevertheless, by using thorium as nuclear fuel this issue is also solved.