Spent V2O5-WO3/TiO2 catalyst processing for valuable metals by soda roasting-water leaching

Choi, In-Hyeok; Kim, Hyerim; Moon, Gyeonghye; Jyothi, Rajesh Kumar; Lee, Jin Young

doi:10.1016/j.hydromet.2017.12.010

Cited by 74 publications

(18 citation statements)

References 26 publications

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“…As compared with gray samples, the peak between 925 and 1000 cm −1 of yellow samples was broader and higher, meaning that there is much stronger interaction among W, V, and Ti species [20]. The stronger interaction between W species and TiO2 anatase lattice could result in lower W leaching efficiency [5]. Thus, the stronger interaction among V-W-Ti and the less content of surface W species of yellow area samples might result in their lower W leaching efficiency.…”

Section: Raman Analysismentioning

confidence: 95%

“…Thus, various approaches have been developed for recovering valuable metals from spent SCR catalysts. As compared with high-temperature roasting or high-pressure leaching method, which means high energy cost and leads to a high concentration of impurities in leaching solutions, such as silicon, Na 2 TiO 3 , Na 2 Ti 3 O 7 [5][6][7], direct leaching with alkali solution under ambient pressure seems more economically acceptable. There are only a few research studies on direct leaching by alkali under ambient pressure (Table 1); all the researches are carried out with specific catalyst, and the leaching efficiency is quite different among the various researches.…”

Section: Introductionmentioning

confidence: 99%

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A Comparative Study in Vanadium and Tungsten Leaching from Various Sources of SCR Catalysts with Local Difference

Miao

et al. 2020

Sustainability

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Direct leaching with NaOH can be an economically acceptable method for vanadium (V) and tungsten (W) recovery from spent selective catalytic reduction (SCR) catalysts. However, different chemical-physical characteristics of catalysts would affect the V and W leaching. In this paper, the V and W leaching behavior of various sources of SCR catalysts with a local difference (yellow and gray color) were systematically investigated with alkali leaching solution under ambient pressure. Different leaching efficiencies from yellow and gray color areas were correlated with oxidation states and species of V and W on catalyst surfaces, as characterized by X-ray photoelectron spectroscopy (XPS), Raman, Fourier transform infrared spectroscopy (FTIR), and other analytic methods. For the V leaching efficiency, the samples from a gray area of catalysts (40.0-51.0%) were lower than that from the yellow area (66.8-69.8%). The higher molar ratio of V 3+ and a lower molar ratio of V 5+ , and the lower total V content on the surface of the samples from the gray area could be the main reasons for the lower V leaching efficiency. As for the W leaching efficiency, the samples from the gray area (44.6-57.3%) were slightly higher than that from the yellow area (38.0-52.6%) of catalysts. The less total W content of surface species and stronger interaction among V-W-Ti of yellow area samples resulted in the lower leaching efficiency. These differential leaching efficiencies needed to be taken into consideration for recovering V and W from spent SCR catalysts.

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Section: Raman Analysismentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

A Comparative Study in Vanadium and Tungsten Leaching from Various Sources of SCR Catalysts with Local Difference

Miao

et al. 2020

Sustainability

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show abstract

“…Several studies have been conducted for the recovery of V and tungsten (W) from a spent SCR catalyst. Soda-roasting and water leaching [8], pressure leaching [9,10] or alkaline leaching [11,12] are employed to extract V and W from a spent SCR catalyst. It is, however, worth noting that about 70-80% of the amount of a spent SCR catalyst feed processed will be generated as a waste if only V and W are recovered.…”

Section: Introductionmentioning

confidence: 99%

Recent Developments in the Recycling of Spent Selective Catalytic Reduction Catalyst in South Korea

et al. 2020

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Spent selective catalytic reduction (SCR) catalyst installed in power and incineration plants is used to convert nitrogen oxide (NOx) gas to nitrogen (N2) gas. Currently, most spent SCR catalyst in South Korea is eventually discarded in landfills. Recently, a novel and efficient recycling process has been developed to recover tungsten (W), vanadium (V) and titanium (Ti) from spent SCR catalyst. In this process, after soda-melting reactions between the spent SCR catalyst and sodium carbonate (Na2CO3) at 1273 K, hydrometallurgical treatments were carried out for the production of high-purity products, such as 99.3% sodium tungstate (Na2WO4), 99.3% vanadium oxide (V2O5) and 99.6% titanium dioxide (TiO2). On the basis of the fundamental investigation of this novel recycling process, process scale-up has been attempted to establish a commercial process. In this paper, recent developments in the recycling process for spent SCR catalyst and the results obtained using the scaled-up process will be discussed. Therefore, this study will provide a practical method for the recovery of W, V and Ti from spent SCR catalyst.

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“…Choi et al . 5 proposed a soda roasting and water leaching process to dissolve vanadium and tungsten. According to their results, vanadium and tungsten from spent SCR catalyst were dissolved with increasing Na 2 CO 3 addition amount and roasting temperature.…”

Section: Introductionmentioning

confidence: 99%

Alkali fusion using sodium carbonate for extraction of vanadium and tungsten for the preparation of synthetic sodium titanate from spent SCR catalyst

Choi

Moon

Lee

et al. 2019

Sci Rep

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Alkali fusion method to extract vanadium and tungsten from spent SCR catalyst and to simultaneously prepare synthetic sodium titanate for the purpose of preparation of feedstock for TiO 2 manufacturing by hydrometallurgical processing was investigated. Based on the Na 2 O-TiO 2 phase diagram and experimentally obtained results, appropriate alkali-fusion temperature and molar ratio (MO x /Na 2 O + MO x ) were determined to prepare soluble vanadium, tungsten salts, and sodium titanate. As results, the extraction efficiency of vanadium and tungsten was >99% and sodium titanate as feedstock for making TiO 2 was obtained under the following alkali fusion conditions: Temperature, 950 °C; reaction time, 20 min; molar ratio, 0.5. When the molar ratio (MO x /Na 2 O + MO x ) was less than 0.5, complete liquidized product (eutectic melt of the feedstock and Na 2 CO 3 ) was obtained at the given conditions. This method, compared to conventional alkali roasting, is advantageous for rapid synthesis of water-soluble compounds for leaching of vanadium and tungsten, and for use as feedstock for the preparation of TiO 2 by hydrometallurgical route.

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Spent V2O5-WO3/TiO2 catalyst processing for valuable metals by soda roasting-water leaching

Cited by 74 publications

References 26 publications

A Comparative Study in Vanadium and Tungsten Leaching from Various Sources of SCR Catalysts with Local Difference

A Comparative Study in Vanadium and Tungsten Leaching from Various Sources of SCR Catalysts with Local Difference

Recent Developments in the Recycling of Spent Selective Catalytic Reduction Catalyst in South Korea

Alkali fusion using sodium carbonate for extraction of vanadium and tungsten for the preparation of synthetic sodium titanate from spent SCR catalyst

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