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Spent catalyst, containing vanadium and tungsten oxide in a TiO2 glass fiber matrix, pose a risk of environmental contamination due to the high toxicity of its metal oxides if leached into the soil when disposed in landfills. Due to the increasing demand of metals and the continuous depletion of primary resources there is an growing necessity for recycling and reprocessing of spent catalysts and other secondary metal sources for environmental and economical reasons. Study of spent SCR catalyst soda roasting process with dissolved NaOH compared with the usual NaOH dry roasting and its influence in the subsequent water leaching. After optimization, the ideal parameters are roasting with 40% NaOH solution for 2h at 973K and DI water leaching for 30minutes, at 298K with a pulp density of 30%. The research results show an important reduction of the roasting temperature and leaching time during the processing of spent SCR catalyst with the objective to recover vanadium and tungsten. Silicon compounds are one of the main impurities leached alongside the valuable metals and in this work, the silicon compounds leached are reduced significantly avoiding the de-silication post-processing of the leach liquor. The main advantage of the proposed process is the increase of the leaching efficiency of vanadium and tungsten in a shorter time regardless of the leaching temperature.
Jong Hyuk Jeon; Ana Belen Cueva Sola; Jin-Young Lee; Rajesh Kumar Jyothi. Novel Eco-friendly Roasting and Leaching Process Development to Recycle Valuable Metals from Spent SCR deNOX Catalyst. 2021, 1 .
AMA StyleJong Hyuk Jeon, Ana Belen Cueva Sola, Jin-Young Lee, Rajesh Kumar Jyothi. Novel Eco-friendly Roasting and Leaching Process Development to Recycle Valuable Metals from Spent SCR deNOX Catalyst. . 2021; ():1.
Chicago/Turabian StyleJong Hyuk Jeon; Ana Belen Cueva Sola; Jin-Young Lee; Rajesh Kumar Jyothi. 2021. "Novel Eco-friendly Roasting and Leaching Process Development to Recycle Valuable Metals from Spent SCR deNOX Catalyst." , no. : 1.
An environmentally sound process was investigated as feasible to extract and separate rare earths from the synthetic leach liquors prepared based on waste permanent magnets composition analogs. Solvent extraction methods were used to screen different extractants to optimize and suggest the proper extraction system to recovery the different rare earth elements (REEs). Various experimental factors, equilibrium pH and impact of the extractant concentration were studied to select the optimum extraction system. Waste permanent magnets were treated in the initial stages with plating separation, sulfuric acid leaching and double salt precipitation. A second leaching process was implemented by hydrochloric acid; the leach liquor was treated by hydrometallurgy processes for the reprocessing and separation of rare earths present. Three phosphorous based commercial extractants Cyanex 272 (bis (2, 4, 4-trimethylpentyl) phosphinic acid), D2EHPA (bis (2, 4, 4-tri-methyl-pentyl) phosphinic acid) and PC 88A (2-ethyl-hexyl-phosphonic acid mono-2-ethyl-hexyl ester) were applied in the present study. Initial experiments suggested that Cyanex 272 is the best reagent for recovery and potential separation between REs, therefore the crowding studies were carried on. From this study appropriate experimental conditions for crowding were optimized to maximize the enrichment of rare earths while separating them.
Jong Hyuk Jeon; Ho-Sung Yoon; Chul-Joo Kim; Kyeong Woo Chung; Rajesh Kumar Jyothi. Environmentally sound technology development for processing of rare earth elements from waste permanent magnets synthetic leach solutions: recovery and separation perspectives. Separation and Purification Technology 2021, 275, 119225 .
AMA StyleJong Hyuk Jeon, Ho-Sung Yoon, Chul-Joo Kim, Kyeong Woo Chung, Rajesh Kumar Jyothi. Environmentally sound technology development for processing of rare earth elements from waste permanent magnets synthetic leach solutions: recovery and separation perspectives. Separation and Purification Technology. 2021; 275 ():119225.
Chicago/Turabian StyleJong Hyuk Jeon; Ho-Sung Yoon; Chul-Joo Kim; Kyeong Woo Chung; Rajesh Kumar Jyothi. 2021. "Environmentally sound technology development for processing of rare earth elements from waste permanent magnets synthetic leach solutions: recovery and separation perspectives." Separation and Purification Technology 275, no. : 119225.
Rare earth elements, by virtue of their role in technological advancements, have become critical commodities over the last few decades. The emerging awareness of environmental pollution associated with primary ore mining and the need for processes to preserve these non-renewable minerals, coupled with the attempt to break China’s monopoly of the REEs production and commercialization, has led to research into alternative sources. The crusade for beneficial use of coal combustion products and the proposal that these CCPs are REE-rich sources have therefore received a widespread attention among other alternatives. This chapter seeks to explain the feasibility of the extraction of REEs from CCPs using ionic liquids. The ability to modify ILs to suit the application necessities allows for extraction at better experimental conditions reducing the overall waste generation of the process. Different types of ionic liquids have been studied for rare earth elements recovery and recycling from secondary sources (scraps, electronic waste) using nonfunctional, monofunctional, and bifunctional ionic liquids. However, the recovery of REEs from the by-products of coal combustion has not been studied in depth despite of them being a rich source of these technological key elements.
Isaac Kwabena Danso; Ana Belen Cueva-Sola; Zubair Masaud; Jin-Young Lee; Rajesh Kumar Jyothi. Ionic Liquids for the Recovery of Rare Earth Elements from Coal Combustion Products. Clean Coal Technologies 2021, 617 -638.
AMA StyleIsaac Kwabena Danso, Ana Belen Cueva-Sola, Zubair Masaud, Jin-Young Lee, Rajesh Kumar Jyothi. Ionic Liquids for the Recovery of Rare Earth Elements from Coal Combustion Products. Clean Coal Technologies. 2021; ():617-638.
Chicago/Turabian StyleIsaac Kwabena Danso; Ana Belen Cueva-Sola; Zubair Masaud; Jin-Young Lee; Rajesh Kumar Jyothi. 2021. "Ionic Liquids for the Recovery of Rare Earth Elements from Coal Combustion Products." Clean Coal Technologies , no. : 617-638.
Rare earth elements (REEs) have obtained a greatest significant in human lives owing to their important roles in various high technology applications. The present method development was deal technology important REEs such as neodymium, terbium and dysprosium, selective extraction with possible separation and recovery studies, successfully. The chloride mediated mixed aqueous solution containing 1500 mg/L each of REEs such as Nd, Tb and Dy was subjected at selective separation of Nd from other associated REEs. Three organo-phosphorous based commercial extracting agents such as Cyanex 272, PC 88A and D2EHPA, were employed for the extraction, possible separation and recovery of rare earth elements. A comparative extraction behavior of all these three extractants as function of time, pH influence, extractant concentration, temperature and diluents were systematically investigated. The extraction tendency of organo-phosphorus reagents towards the extraction of either of the REEs follows of the sequence as: D2EHPA > PC 88A > Cyanex 272. The thermodynamic behavior of either of the extractants on liquid–liquid extraction processing of REEs was investigated and thermodynamic calculations were calculated and presented. Substantial recovery of neodymium oxalate followed by its calcined product as neodymium oxide was ascertained from XRD study and SEM–EDS analysis.
Verónica Cristina Arellano Ruiz; Rambabu Kuchi; Pankaj Kumar Parhi; Jin-Young Lee; Rajesh Kumar Jyothi. Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives. Scientific Reports 2020, 10, 1 -13.
AMA StyleVerónica Cristina Arellano Ruiz, Rambabu Kuchi, Pankaj Kumar Parhi, Jin-Young Lee, Rajesh Kumar Jyothi. Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives. Scientific Reports. 2020; 10 (1):1-13.
Chicago/Turabian StyleVerónica Cristina Arellano Ruiz; Rambabu Kuchi; Pankaj Kumar Parhi; Jin-Young Lee; Rajesh Kumar Jyothi. 2020. "Environmentally friendly comprehensive hydrometallurgical method development for neodymium recovery from mixed rare earth aqueous solutions using organo-phosphorus derivatives." Scientific Reports 10, no. 1: 1-13.
A complete extraction and stripping process to obtain enriched vanadium and tungsten concentrate from spent SCR catalyst leach liquor.
Ana Belen Cueva Sola; Pankaj Kumar Parhi; Jin-Young Lee; Hee Nam Kang; Rajesh Kumar Jyothi. Environmentally friendly approach to recover vanadium and tungsten from spent SCR catalyst leach liquors using Aliquat 336. RSC Advances 2020, 10, 19736 -19746.
AMA StyleAna Belen Cueva Sola, Pankaj Kumar Parhi, Jin-Young Lee, Hee Nam Kang, Rajesh Kumar Jyothi. Environmentally friendly approach to recover vanadium and tungsten from spent SCR catalyst leach liquors using Aliquat 336. RSC Advances. 2020; 10 (34):19736-19746.
Chicago/Turabian StyleAna Belen Cueva Sola; Pankaj Kumar Parhi; Jin-Young Lee; Hee Nam Kang; Rajesh Kumar Jyothi. 2020. "Environmentally friendly approach to recover vanadium and tungsten from spent SCR catalyst leach liquors using Aliquat 336." RSC Advances 10, no. 34: 19736-19746.
Rare earth elements (REEs) are vital components of high-tech electrical and electronic based materials. In the global scenario, the deposits of natural rare earth elements (REEs) are limited except for countries such as China. This has led to a dependence on major secondary rare earth-bearing sources such as battery waste, scrap alloy, spent magnets, spent catalysts, waste light-emitting diodes (LEDs), and fly ash for a substantial recovery of REEs for their use. Recycling REEs from these secondary waste sources by hydrometallurgical routes appears to be a sustainable approach with low waste generation, few emissions, low energy consumption, economically feasible, and environmentally friendly. In most of the reported studies, secondary waste is subjected to chemical and or bioleaching followed by solvent extraction processes for clean separation of REEs. Subsequently, rare earth compound(s) are recovered through precipitation. Solvent extraction (liquid-liquid extraction) is one of the most vital stages in the overall process as REEs (light and heavy rare earths) exhibit a low separation tendency while being extracted with various solvent reagents from corresponding aqueous media. This review provides an in-depth discussion on the recycling strategies implemented to obtain REEs from numerous secondary wastes; extraction behavior of REEs; challenges, advantages, and disadvantages of the proposed methodologies; as well as proposed flowsheets for clean separation and recovery of REEs. In addition, the role of REEs in renewable and green energy technologies and the future aspects of the reprocessing technology of secondary REE sources are summarized and reported.
Rajesh Kumar Jyothi; Thriveni Thenepalli; Ji Whan Ahn; Pankaj Kumar Parhi; Kyeong Woo Chung; Jin-Young Lee. Review of rare earth elements recovery from secondary resources for clean energy technologies: Grand opportunities to create wealth from waste. Journal of Cleaner Production 2020, 267, 122048 .
AMA StyleRajesh Kumar Jyothi, Thriveni Thenepalli, Ji Whan Ahn, Pankaj Kumar Parhi, Kyeong Woo Chung, Jin-Young Lee. Review of rare earth elements recovery from secondary resources for clean energy technologies: Grand opportunities to create wealth from waste. Journal of Cleaner Production. 2020; 267 ():122048.
Chicago/Turabian StyleRajesh Kumar Jyothi; Thriveni Thenepalli; Ji Whan Ahn; Pankaj Kumar Parhi; Kyeong Woo Chung; Jin-Young Lee. 2020. "Review of rare earth elements recovery from secondary resources for clean energy technologies: Grand opportunities to create wealth from waste." Journal of Cleaner Production 267, no. : 122048.
Separation and purification of thorium from monazite leach liquors was investigated by counter current extraction process. The Primene JM-T (mixture of highly branched C16 to C22 tertiary alkyl primary amine isomers) was used as an extractant and kerosene as a diluent for the present investigation. Extraction isotherm was plotted at the condition: 0.1 mol/L Primene JM-T, A:O = 3:1, which predicted on requirement of 3 stages for quantitative extraction of thorium. A 99.9% extraction of thorium from the leach liquor was achieved at the optimum conditions leaving 0.1 mg/L of the metal in the raffinate phase. The predicted three counter current stripping stages from the stripping were validated using 0.5 mol/L HCl + 0.5 mol/L NH4Cl as the stripping agent. XRD analysis proved the high purity thorium oxalate precipitated and recovered from monazite.
Kyeong Woo Chung; Ho-Sung Yoon; Chul-Joo Kim; Rajesh Kumar Jyothi. Separation, purification and recovery of thorium from monazite leach liquors by counter-current extraction process. Journal of Radioanalytical and Nuclear Chemistry 2020, 324, 245 -255.
AMA StyleKyeong Woo Chung, Ho-Sung Yoon, Chul-Joo Kim, Rajesh Kumar Jyothi. Separation, purification and recovery of thorium from monazite leach liquors by counter-current extraction process. Journal of Radioanalytical and Nuclear Chemistry. 2020; 324 (1):245-255.
Chicago/Turabian StyleKyeong Woo Chung; Ho-Sung Yoon; Chul-Joo Kim; Rajesh Kumar Jyothi. 2020. "Separation, purification and recovery of thorium from monazite leach liquors by counter-current extraction process." Journal of Radioanalytical and Nuclear Chemistry 324, no. 1: 245-255.
The scrap magnet contains significant amounts of rare earth metals such as neodymium, praseodymium, dysprosium, and terbium. In the twenty-first century, faster growing rate of hi-tech industrialization leads to the generation of the secondary wastes across the globe, which is becoming an environmental concern. To resolve the environmental issue vis-à-vis to meet the demand for rare earth metals, this investigation is focused on the development of a suitable process for extraction of Nd, Dy, Pr, and Tb from the scrap permanent magnet using leaching followed by solvent extraction. During leaching, oxidation roasting process was adopted to minimize the dissolution of iron. The resulted leach liquor was subjected to liquid–liquid extraction of Nd, Pr, Dy, and Tb using organophosphorus derivatives reagents. Process optimization followed by extraction isotherm study was carried out to obtain quantitative extraction of these metals from the aqueous media. The crowding effect was further investigated to improve the separation factor of the RE metals and reported.
Rajesh Kumar Jyothi; Kyeong Woo Chung; Chul-Joo Kim; Ho-Sung Yoon. Recovery of Rare Earth Elements from Waste Permanent Magnets Leach Liquors. The Minerals, Metals & Materials Series 2020, 335 -345.
AMA StyleRajesh Kumar Jyothi, Kyeong Woo Chung, Chul-Joo Kim, Ho-Sung Yoon. Recovery of Rare Earth Elements from Waste Permanent Magnets Leach Liquors. The Minerals, Metals & Materials Series. 2020; ():335-345.
Chicago/Turabian StyleRajesh Kumar Jyothi; Kyeong Woo Chung; Chul-Joo Kim; Ho-Sung Yoon. 2020. "Recovery of Rare Earth Elements from Waste Permanent Magnets Leach Liquors." The Minerals, Metals & Materials Series , no. : 335-345.
The technology for extraction and recovery of the thorium from its source is one of the significant areas of research Present investigation deals on development of a process for extraction of thorium and its separation from the uranium and rare earths contained Korean monazite leach liquor. In the preliminary study, sulfuric acid treatment of monazite concentrate followed by water leaching was carried out. Furthermore double salt precipitation and acid leaching lead to produce thorium rich leach liquor. Various commercial extractants accomplishing D2EHPA, PC88A, Amine and Primene JM-T were tested and optimized for selective separation of thorium. The effective extraction behavior of thorium followed the order as; Primene JM-T > D2EHPA > PC88A and high separation factor was resulted at high acidity (2.5 mol/L) of leach liquor, ensuring on high selectivity of Primene JM-T towards loading of Th. The co-extraction of cerium was prevented by changing thorium oxidation state using Fe2+ and H2O2 and reported. The co-extraction of other associated rare earths was scrubbed with sulfuric acid solutions. Subsequently, stripping studies were carryout with two different types of mineral acids and it was quantitative using high acid concentration (5 mol/L).
Kyeong Woo Chung; Ho-Sung Yoon; Chul-Joo Kim; Jin-Young Lee; Rajesh Kumar Jyothi. Solvent extraction, separation and recovery of thorium from Korean monazite leach liquors for nuclear industry applications. Journal of Industrial and Engineering Chemistry 2019, 83, 72 -80.
AMA StyleKyeong Woo Chung, Ho-Sung Yoon, Chul-Joo Kim, Jin-Young Lee, Rajesh Kumar Jyothi. Solvent extraction, separation and recovery of thorium from Korean monazite leach liquors for nuclear industry applications. Journal of Industrial and Engineering Chemistry. 2019; 83 ():72-80.
Chicago/Turabian StyleKyeong Woo Chung; Ho-Sung Yoon; Chul-Joo Kim; Jin-Young Lee; Rajesh Kumar Jyothi. 2019. "Solvent extraction, separation and recovery of thorium from Korean monazite leach liquors for nuclear industry applications." Journal of Industrial and Engineering Chemistry 83, no. : 72-80.
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 TiO2 manufacturing by hydrometallurgical processing was investigated. Based on the Na2O-TiO2 phase diagram and experimentally obtained results, appropriate alkali-fusion temperature and molar ratio (MOx/Na2O + MOx) 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 TiO2 was obtained under the following alkali fusion conditions: Temperature, 950 °C; reaction time, 20 min; molar ratio, 0.5. When the molar ratio (MOx/Na2O + MOx) was less than 0.5, complete liquidized product (eutectic melt of the feedstock and Na2CO3) 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 TiO2 by hydrometallurgical route.
In-Hyeok Choi; Gyeonghye Moon; Jin-Young Lee; Rajesh Kumar Jyothi. Alkali fusion using sodium carbonate for extraction of vanadium and tungsten for the preparation of synthetic sodium titanate from spent SCR catalyst. Scientific Reports 2019, 9, 1 -8.
AMA StyleIn-Hyeok Choi, Gyeonghye Moon, Jin-Young Lee, Rajesh Kumar Jyothi. Alkali fusion using sodium carbonate for extraction of vanadium and tungsten for the preparation of synthetic sodium titanate from spent SCR catalyst. Scientific Reports. 2019; 9 (1):1-8.
Chicago/Turabian StyleIn-Hyeok Choi; Gyeonghye Moon; Jin-Young Lee; Rajesh Kumar Jyothi. 2019. "Alkali fusion using sodium carbonate for extraction of vanadium and tungsten for the preparation of synthetic sodium titanate from spent SCR catalyst." Scientific Reports 9, no. 1: 1-8.
Rajesh Kumar Jyothi; Hae-Rim Kim; Joon Soo Kim; Kyeong-Woo Chung; Jin-Young Lee. Diluents Role in Extraction and Possible Separation of Light Rare Earth Elements from Chloride Solutions by using Cyanex® 272 used as an Extractant. Korean Journal of Metals and Materials 2018, 56, 763 -771.
AMA StyleRajesh Kumar Jyothi, Hae-Rim Kim, Joon Soo Kim, Kyeong-Woo Chung, Jin-Young Lee. Diluents Role in Extraction and Possible Separation of Light Rare Earth Elements from Chloride Solutions by using Cyanex® 272 used as an Extractant. Korean Journal of Metals and Materials. 2018; 56 (10):763-771.
Chicago/Turabian StyleRajesh Kumar Jyothi; Hae-Rim Kim; Joon Soo Kim; Kyeong-Woo Chung; Jin-Young Lee. 2018. "Diluents Role in Extraction and Possible Separation of Light Rare Earth Elements from Chloride Solutions by using Cyanex® 272 used as an Extractant." Korean Journal of Metals and Materials 56, no. 10: 763-771.
This paper presents the direct extraction, which works by means of pressure leaching, of vanadium and tungsten from the spent SCR catalysts using a caustic soda. The experimental parameters were concentration of NaOH (aq), the particle size of the feedstock, the temperature, and the S/L ratio. The results of an assessment of the proposed method found that pressure leaching using a caustic soda can more effectively dissolve vanadium and tungsten from the spent SCR catalysts than atmospheric alkaline leaching. The dissolution efficiency of vanadium and tungsten tended to increase with an increase in the concentration of NaOH (aq), a higher temperature and a decrease in the particle size of the feedstock used. The S/L ratio, which affected the dissolution efficiency of vanadium and tungsten, differed depending on the concentration of NaOH (aq). The optimum conditions for the extraction of vanadium and tungsten by pressure leaching were as follows: concentration of NaOH (aq), 3 mol/L; temperature, 250°C; particle size distribution; <150 μm; S/L ratio, 0.4. With these optimum conditions, the dissolution efficiency of vanadium and tungsten were found to be 91.5% and 87%, respectively. The established method for the direct extraction of vanadium and tungsten from spent SCR catalysts is effective and environmentally sound compared to atmospheric alkaline leaching.
In-Hyeok Choi; Gyeonghye Moon; Jin-Youn Lee; Rajesh Kumar Jyothi. Extraction of tungsten and vanadium from spent selective catalytic reduction catalyst for stationary application by pressure leaching process. Journal of Cleaner Production 2018, 197, 163 -169.
AMA StyleIn-Hyeok Choi, Gyeonghye Moon, Jin-Youn Lee, Rajesh Kumar Jyothi. Extraction of tungsten and vanadium from spent selective catalytic reduction catalyst for stationary application by pressure leaching process. Journal of Cleaner Production. 2018; 197 ():163-169.
Chicago/Turabian StyleIn-Hyeok Choi; Gyeonghye Moon; Jin-Youn Lee; Rajesh Kumar Jyothi. 2018. "Extraction of tungsten and vanadium from spent selective catalytic reduction catalyst for stationary application by pressure leaching process." Journal of Cleaner Production 197, no. : 163-169.
Currently, spent V2O5–WO3/TiO2 catalysts contribute significant amounts of solid waste following increasing levels of global demand. V2O5–WO3/TiO2 catalysts usually consist of TiO2 anatase as a supporting oxide, vanadium as a catalytic agent, and other promoters such as tungsten, silicon, and calcium. Although vanadium is the main catalytic agent, a relatively high content of tungsten (WO3, 7–10 wt%) typically exists compared to vanadium (0.5–1.5 wt%). Considering the irreplaceable properties and industrial importance of tungsten, a feasible method for the recycling of spent V2O5–WO3/TiO2 catalyst should be established to utilize it as a secondary source. This paper presents a process to recover tungsten from spent V2O5–WO3/TiO2 catalyst. The processes proposed here involving roasting, decomposition using HCl, ammonia leaching, and crystallization. Within the process, ammonium paratungstate (71 wt% as WO3) is obtained as a final product. The total yield rate of tungsten from feedstock was found to be 96.3%.
In-Hyeok Choi; Gyeonghye Moon; Jin-Young Lee; Rajesh Kumar Jyothi. Recovery of Tungsten from Spent V2O5–WO3/TiO2 Catalyst. Proceedings of the International Conference on Martensitic Transformations: Chicago 2018, 2455 -2469.
AMA StyleIn-Hyeok Choi, Gyeonghye Moon, Jin-Young Lee, Rajesh Kumar Jyothi. Recovery of Tungsten from Spent V2O5–WO3/TiO2 Catalyst. Proceedings of the International Conference on Martensitic Transformations: Chicago. 2018; ():2455-2469.
Chicago/Turabian StyleIn-Hyeok Choi; Gyeonghye Moon; Jin-Young Lee; Rajesh Kumar Jyothi. 2018. "Recovery of Tungsten from Spent V2O5–WO3/TiO2 Catalyst." Proceedings of the International Conference on Martensitic Transformations: Chicago , no. : 2455-2469.
This paper deals with the recovery of tungsten as synthetic CaWO4 from spent V2O5-WO3/TiO2 (selective catalytic reduction, SCR) catalyst. The newly developed process included the systematic experimental steps (roasting, decomposition (using HCl solution), leaching (using NaOH), and precipitation) to recover tungsten as CaWO4. The results revealed that the effect of roasting of spent SCR catalyst was significant for the extraction of tungsten. Furthermore, CaO addition in the roasting process promoted chemical equilibrium for the formation of CaWO4, and extraction efficiency of tungsten was increased simultaneously. Decomposition process revealed that 4 mol·L−1 of HCl solution was the best condition with considerable degree of removal (92.5%) of vanadium along with negligible loss of tungsten. The most appropriate concentration of NaOH (aq) to dissolve tungstic acid (H2WO4) from the decomposed sample was 1 mol L−1 (>99% tungsten yield) in accordance with minimized concentration of foreign metals (Si, Al, Fe). The maximum amount of tungsten (>99%) was obtained from the sodium tungstate solution as synthetic CaWO4 using CaCl2 (molar ratio (CaCl2/WO3): 1). The best experimental conditions for the precipitation were under following conditions: temperature, 50 °C; equilibrium pH, 8–10; molar ratio (CaCl2/WO3), “1”. The content of CaWO4 in the final product was 96.1 wt%. The overall yield of tungsten from the feedstock using the proposed process was 96.4%.
In-Hyeok Choi; Gyeonghye Moon; Jin-Young Lee; Rajesh Kumar Jyothi. Hydrometallurgical processing of spent selective catalytic reduction (SCR) catalyst for recovery of tungsten. Hydrometallurgy 2018, 178, 137 -145.
AMA StyleIn-Hyeok Choi, Gyeonghye Moon, Jin-Young Lee, Rajesh Kumar Jyothi. Hydrometallurgical processing of spent selective catalytic reduction (SCR) catalyst for recovery of tungsten. Hydrometallurgy. 2018; 178 ():137-145.
Chicago/Turabian StyleIn-Hyeok Choi; Gyeonghye Moon; Jin-Young Lee; Rajesh Kumar Jyothi. 2018. "Hydrometallurgical processing of spent selective catalytic reduction (SCR) catalyst for recovery of tungsten." Hydrometallurgy 178, no. : 137-145.
Modeling uranium dioxide pellet process from ammonium uranyl carbonate - derived uranium dioxide powder (UO2 ex-AUC powder) and predicting fuel rod temperature distribution were reported in the paper. Response surface methodology (RSM) and FRAPCON-4.0 code were used to model the process and to predict the fuel rod temperature under steady-state operating condition. Fuel rod design of AP-1000 designed by Westinghouse Electric Corporation, in these the pellet fabrication parameters are from the study, were input data for the code. The predictive data were suggested the relationship between the fabrication parameters of UO2 pellets and their temperature image in nuclear reactor.
Nguyen Trong Hung; Le Ba Thuan; Tran Chi Thanh; Hoang Nhuan; Do Van Khoai; Nguyen Van Tung; Jin-Young Lee; Rajesh Kumar Jyothi. Modeling the UO2 ex-AUC pellet process and predicting the fuel rod temperature distribution under steady-state operating condition. Journal of Nuclear Materials 2018, 504, 191 -197.
AMA StyleNguyen Trong Hung, Le Ba Thuan, Tran Chi Thanh, Hoang Nhuan, Do Van Khoai, Nguyen Van Tung, Jin-Young Lee, Rajesh Kumar Jyothi. Modeling the UO2 ex-AUC pellet process and predicting the fuel rod temperature distribution under steady-state operating condition. Journal of Nuclear Materials. 2018; 504 ():191-197.
Chicago/Turabian StyleNguyen Trong Hung; Le Ba Thuan; Tran Chi Thanh; Hoang Nhuan; Do Van Khoai; Nguyen Van Tung; Jin-Young Lee; Rajesh Kumar Jyothi. 2018. "Modeling the UO2 ex-AUC pellet process and predicting the fuel rod temperature distribution under steady-state operating condition." Journal of Nuclear Materials 504, no. : 191-197.
In-Hyeok Choi; Hye-Rim Kim; Gyeonghye Moon; Rajesh Kumar Jyothi; Jin-Young Lee. Spent V2O5-WO3/TiO2 catalyst processing for valuable metals by soda roasting-water leaching. Hydrometallurgy 2018, 175, 292 -299.
AMA StyleIn-Hyeok Choi, Hye-Rim Kim, Gyeonghye Moon, Rajesh Kumar Jyothi, Jin-Young Lee. Spent V2O5-WO3/TiO2 catalyst processing for valuable metals by soda roasting-water leaching. Hydrometallurgy. 2018; 175 ():292-299.
Chicago/Turabian StyleIn-Hyeok Choi; Hye-Rim Kim; Gyeonghye Moon; Rajesh Kumar Jyothi; Jin-Young Lee. 2018. "Spent V2O5-WO3/TiO2 catalyst processing for valuable metals by soda roasting-water leaching." Hydrometallurgy 175, no. : 292-299.
Nguyen Trong Hung; Le Ba Thuan; Nguyen Van Tung; Nguyen Thanh Thuy; Jin-Young Lee; Rajesh Kumar Jyothi. The UO 2 ex-ADU powder preparation and pellet sintering for optimum efficiency: experimental and modeling studies. Journal of Nuclear Materials 2017, 496, 177 -181.
AMA StyleNguyen Trong Hung, Le Ba Thuan, Nguyen Van Tung, Nguyen Thanh Thuy, Jin-Young Lee, Rajesh Kumar Jyothi. The UO 2 ex-ADU powder preparation and pellet sintering for optimum efficiency: experimental and modeling studies. Journal of Nuclear Materials. 2017; 496 ():177-181.
Chicago/Turabian StyleNguyen Trong Hung; Le Ba Thuan; Nguyen Van Tung; Nguyen Thanh Thuy; Jin-Young Lee; Rajesh Kumar Jyothi. 2017. "The UO 2 ex-ADU powder preparation and pellet sintering for optimum efficiency: experimental and modeling studies." Journal of Nuclear Materials 496, no. : 177-181.
Nguyen Trong Hung; Le Ba Thuan; Do Van Khoai; Jin-Young Lee; Rajesh Kumar Jyothi. Modeling conversion of ammonium diuranate (ADU) into uranium dioxide (UO2) powder. Journal of Nuclear Materials 2016, 479, 483 -488.
AMA StyleNguyen Trong Hung, Le Ba Thuan, Do Van Khoai, Jin-Young Lee, Rajesh Kumar Jyothi. Modeling conversion of ammonium diuranate (ADU) into uranium dioxide (UO2) powder. Journal of Nuclear Materials. 2016; 479 ():483-488.
Chicago/Turabian StyleNguyen Trong Hung; Le Ba Thuan; Do Van Khoai; Jin-Young Lee; Rajesh Kumar Jyothi. 2016. "Modeling conversion of ammonium diuranate (ADU) into uranium dioxide (UO2) powder." Journal of Nuclear Materials 479, no. : 483-488.
Macrocyclic compounds (crown ethers), specifically 18-crown-6 (18-C-6), benzo-15-crown-5 (B-15-C-5), di-benzo-18-crown-6 (DB-18-C-6) and di-cyclohexano-18-crown-6 (DC-18C-6), are used as extractants as well as synergists with amine-group extractants. Platinum and rhodium belong to platinum-group metals (PGMs) and have very similar ionic radii and similar properties. The separation of PGMs is most useful for the preparation of functional materials. Macrocyclic compounds are tested for platinum and rhodium separation and are found to achieve marginal separation. Amines (used as extractants) are paired with macrocyclic compounds (used as synergists), and the separation factor between platinum and rhodium is increased with synergistic enhancement from a chloride solution. The present study discusses extraction chemistry, separation factors and the synergy between platinum and rhodium from chloride solutions. To ensure accurate data, the aqueous samples in this study are analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES).
Rajesh Kumar Jyothi; Jin-Young Lee. The role of macrocyclic compounds in the extraction and possible separation of platinum and rhodium from chloride solutions. Scientific Reports 2016, 6, 27668 .
AMA StyleRajesh Kumar Jyothi, Jin-Young Lee. The role of macrocyclic compounds in the extraction and possible separation of platinum and rhodium from chloride solutions. Scientific Reports. 2016; 6 (1):27668.
Chicago/Turabian StyleRajesh Kumar Jyothi; Jin-Young Lee. 2016. "The role of macrocyclic compounds in the extraction and possible separation of platinum and rhodium from chloride solutions." Scientific Reports 6, no. 1: 27668.
The aim of the present study is to investigate the extraction, separation and recovery of the indivisible metals of dysprosium and neodymium from permanent magnets scrap (PMS) leach liquor solutions. Organo-phosphorous extractant namely 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (PC 88A) was employed and optimised various experimental parameters to recover dysprosium. The present experimental development focused on Dy separation from Nd and recovery by suitable mineral acids. Fundamental studies of the effect of time, pH and extractant concentration on the metal separation were conducted followed by proposal of a mechanism for extraction. Process development included generation of McCabe–Thiele diagrams and counter current extraction (CCE) studies. Generation of loaded organic phase from the CCE process was followed by scrubbing studies and final recovery of Dy. Comparisons were made between two types of phase ratios as well as with already reported methods on title metal ions extraction and separation processing. For the metal content analysis in the aqueous samples, advanced analytical instrument such as inductively coupled plasma spectrometer (ICP-OES) was used to obtain sensitive and accurate data.
Hye Sun Yoon; Chul Jin Kim; Kyeong Woo Chung; Soo Dong Kim; Jyothi Rajesh Kumar. Process development for recovery of dysprosium from permanent magnet scraps leach liquor by hydrometallurgical techniques. Canadian Metallurgical Quarterly 2015, 54, 318 -327.
AMA StyleHye Sun Yoon, Chul Jin Kim, Kyeong Woo Chung, Soo Dong Kim, Jyothi Rajesh Kumar. Process development for recovery of dysprosium from permanent magnet scraps leach liquor by hydrometallurgical techniques. Canadian Metallurgical Quarterly. 2015; 54 (3):318-327.
Chicago/Turabian StyleHye Sun Yoon; Chul Jin Kim; Kyeong Woo Chung; Soo Dong Kim; Jyothi Rajesh Kumar. 2015. "Process development for recovery of dysprosium from permanent magnet scraps leach liquor by hydrometallurgical techniques." Canadian Metallurgical Quarterly 54, no. 3: 318-327.