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2 for Energy-Efficient Windows
Published in Yi Long, Yanfeng Gao, Vanadium Dioxide-Based Thermochromic Smart Windows, 2021
Gao et al. reported for the first time the synthesis of W-doped VO2 snowflake powders by using V2O5 and oxalic acid mingled with a small amount of tungstic acid by one-step hydrothermal reactions at 240°C for 7 days. The adulterating agent tungstic acid plays a key role in the synthesis of rutile-phase VO2, and the W-doped VO2 shows a reduced Tc [82]. VO2 with both high-crystallinity-star-shape and hollow-sphere-shape morphologies was produced via direct hydrothermal techniques by Ban et al., and the VO2 films displayed significant thermal stability (about 300°C) and strong optical modulation in the IR region [83]. The star-shaped VO2(D) was synthesized by the hydrothermal treatment of ammonium metavanadate and formic acid, which can be further transformed into VO2(M) through mild annealing treatment. The IR modulation amplitude, phase transition temperature, and hysteresis width of VO2 can be regulated by changing the annealing conditions [36]. By similar a hydrothermal-calcination method, Gao et al. prepared VO2(D) with various micronanostructures that can be converted to VO2(M). The obtained VO2(M) has a low Tc (about 41°C) and a small hysteresis width (6.6°C), and can be a suitable candidate for smart windows [38].
Heavy Metals
Published in Abhik Gupta, Heavy Metal and Metalloid Contamination of Surface and Underground Water, 2020
Vanadium has an atomic number of 23, an atomic weight of 50.942, and a density of 6.11 g cm–3. The major ores of vanadium include patronite or vanadium sulfide, which occurs in Peru, and descloizite or lead-zinc vanadate, found in southern Africa. Vanadinite [Pb5(VO4)3Cl], roscoelite [K(V3+, Al)2(AlSi3O10)(OH)2], and carnotite [K2(UO)2(VO4)2·3H2O] are the other important vanadium-containing ores. Of these, carnotite is a radioactive mineral containing uranium. Other sources comprise crude petroleum, flue-gas deposits from oil-fired furnaces, and slags from ferrovanadium. The most important use of vanadium is in making ferrovanadium, which finds use in high-speed steel and tool-grade steel. Vanadium augments tensile strength and improves the rust resistance of steel. Several vanadium compounds including sulfates and tetrachlorides are used as mordant, silicates as catalysts, and dioxides and trioxides in metallurgy. Vanadium pentoxide (V2O5) is used as an industrial catalyst, in photography, textile, and ceramics, while ammonium metavanadate (NH4VO3) acts as a catalyst, in the photographic and textile industries, and as a reagent in analytical chemistry.
Extraction of Vanadium(V) from Mixed Chloride/Thiocyanate Solutions with Two Commercial Solvating Extractants
Published in Solvent Extraction and Ion Exchange, 2018
Soad. E. Rizk, Naglaa. E. El-Hefny, Jacqueline. A. Daoud
Vanadium was finally recovered from the strip solution by precipitation as ammonium metavanadate and then converted into V2O5 of commercial grade (>98%) by calcination of the dried precipitate.[32] The flow chart of the proposed process for the efficient separation of V(V) from spent catalyst leach liquor used in the production of sulfuric acid industry is given in Fig. 10.
A Novel Process for Manufacturing Vanadium Dioxide(VO2) as a resource of Vanadium Electrolyte from Vanadium Pentoxide(V2O5)
Published in Geosystem Engineering, 2022
Byung-Su Kim, Tae-Gong Ryu, Jihyuk Choi, Tae Jun Park, Hankwon Chang, JeongHyun Yoo, Chang-Youl Suh, Sung-Wook Cho, Kimin Roh
As described in the previous experimental method, Figure 2 shows the XRD analysis result of the powder prepared from industrial vanadium pentoxide (V2O5) chips by the wet process. As shown in Figure 2, the prepared powder was confirmed to be ammonium metavanadate (NH4VO3). Thus, all subsequent experiments used the prepared ammonium metavanadate powder.