HYDROMETALLURGY
·
2019
·
IF 3.465
Xuexin Chen,Hui Wang,Baijun Yan
In order to recover vanadium from vanadium-bearing black shale efficiently, a hydrometallurgical process is developed in this paper to treat the concentrate beneficiated from stone coal ore, in which the vanadium mainly occurs in the form of Fe 3- x V x O 4 spinel. At the first step, the leaching behaviors of Fe and V from the concentrate by using sulfuric acid solution are investigated in detail. The extraction rates of vanadium and iron could reach 92.5% and 98.5% respectively under the optimum leaching conditions of leaching temperature of 90 °C, sulfuric acid concentration of 25 wt%, leaching time of 90 min, L/S mass ratio of 30 and stirring speed of 600 rpm. Secondly, the iron impurity in the pregnant solution is removed efficiently by the precipitation method with Fe 2 O 3 as nucleating agent. The effect of pH value, the amount of Fe 2 O 3 nucleating agent and the precipitating time on the removal of iron and losing of vanadium are systematically investigated, and thereby >99.7% iron impurity can be removed with the loss rate of vanadium not higher than 2.5%. Finally, vanadium is precipitated from the purified leach solution as ammonium poly-vanadate by adding ammonium sulfate , and then the product of V 2 O 5 is obtained by calcining the ammonium poly-vanadate. The purity of V 2 O 5 powder can reach 92.0% approximately.
研究领域:
冶金学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2022
·
IF 9.136
Linquan Sun,Xukun Zhang,Lina Wang,Hongdong Yu,Fancheng Meng,Tao Qi,Yihe Peng
A fluoride-free solvent extraction method for niobium separation in leached sulfuric mother liquor of ilmenorutile was proposed in this paper. The extraction system comprising trioctyl tertiary amine (N235) and 4-methyl-2-pentanone (MIBK) demonstrated good extraction efficiency and selectivity of niobium over titanium and iron impurities in sulfuric acid–oxalate solutions. Details of extraction, scrubbing, and stripping processes were investigated herein, and its practical effectiveness in both batch and multi-stage simulated counter-current modes was verified. Over 73.8% niobium was extracted under optimum conditions, and only 2.8% titanium and 1.7% iron were co-extracted. The recovery of niobium reached 99.1% in the four-stage simulated counter-current extraction tests. In the three-stage simulated counter-current stripping tests, the stripping efficiency of niobium reached 99.7% with 2.0 mol/L HNO 3 . Qualified niobium oxide products were prepared. The enthalpy change, entropy change, and the standard Gibbs free energy change (Δ H o , Δ S o , and Δ G o , respectively) corroborated the exothermicity, orderliness, and spontaneity of the reaction. The possible composition of the extraction complex was [NbO(C 2 O 4 ) 2 (H 2 O) 2 ] − , as supported by a Fourier transform infrared spectroscopy and ultraviolet–visible spectrophotometry. The extraction mechanism was inferred to be the outer-sphere complexation through physical binding which was the association of R 3 NH + in N235 with the [NbO(C 2 O 4 ) 2 (H 2 O) 2 ] − . A preliminary mass balance indicated that 203.92 g Nb 2 O 5 was generated from 1000 g raw material ilmenorutile.
研究领域:
冶金学
·
化学工程
✓ 已验证
DOI
高影响因子
Silicon
·
2020
·Vol. 13
·期 2
·531-541
·
IF 1.499
Li Feifei,Jiang Xuesong,Zuo Qiuxia,Li Jingwei,Ban Boyuan,Chen Jian
Iron is a major impurity in quartz sand and must be strictly removed in many applications. However, the iron removal rate in most of the conventional purification process is not high enough. In this study, a fast, low-energy consuming, environment-friendly and simple process for purifying quartz is demonstrated by a combination of microwave heating and ultrasound-assisted acid leaching treatment. Using the characteristics of selective heating of microwave, the micro-inclusions burst and generate cracks in the surrounding quartz matrix far below the α/β phase transition temperature, which enables removal of the impurities in the subsequent processing steps and reduces iron diffusion into the quartz matrix. Microwave process sequence, time, and temperature are all important factors, and appropriate parameters need to be explored. Ultrasound can assist acid leaching removal of Fe impurities through the cracks. Under optimized conditions, the iron content can be reduced to below 0.167 ppmw with one single purification pass.
研究领域:
材料科学
·
环境工程
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产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE ELECTROCHEMISTRY
·
2024
·Vol. 28
·期 8
·2547-2560
·
IF 2.6
Wan Huan,Wang Wei,Bu Lu-xia
In this study, Al-Fe and Al-Fe-Mn alloy anodes are prepared and examined. The influence of impurity Fe on the microstructure and properties of Al alloy anodes is investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and electrochemical testing techniques. The results reveal that the presence of impurity Fe in Al alloys significantly shifts the open-circuit potential of the Al anode towards the positive side and reduces its discharge efficiency. However, the adverse impact of impurity Fe is mitigated by alloying with Mn. Specifically, the open-circuit potential of Al-0.20%Fe-0.20%Mn anodes is observed to shift negatively by 70 mV when compared to that of Al-0.20%Fe in a 3 M KOH solution. Furthermore, the anode utilization of Al-0.20%Fe-0.20%Mn anodes, following continuous discharge at 30 mA·cm −2 and 100 mA·cm −2 for 30 min, is found to be 70% and 52% higher, respectively, than that of Al-0.20%Fe anodes. This highlights the effectiveness of Mn modification as a preferable approach to ameliorate the detrimental effects of impurity Fe.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 9
·期 8
·1819-1829
·
IF 7.779
Jinghua Liu,Hualan Li,Jiayang Cai,Jingyan Liu,Yansheng Liu,Zijun Sun,Xiong He,Dezhi Qu,Xin Li
Herein, we employ a partial phase conversion strategy to transform cobalt/nickel carbonate hydroxide (CoxNiyCH) nanosheet arrays in an Fe-containing KOH electrolyte. The optimized sample exhibits remarkable electrocatalytic activity (η50 = 256 mV, 51 mV dec−1) and good stability (18 h) with negligible morphology change in a 1 M KOH solution, outperforming most reported cobalt–nickel-based electrocatalysts. From our research, it is found that the Fe impurity in the KOH electrolyte plays an important role in achieving high OER performance. The heterostructure caused by the partial phase transformation of CoxNiyCH can enhance the conductivity and stability along with providing more effective active sites.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2022
·
IF 8.047
Jiang Li,Heyang Liu,Zhidong An,Yue Kong,Lei Huang,Delong Duan,Ran Long,Piaoping Yang,Yuan-Ye Jiang,Jiaxing Liu,Junjie Zhang,Tong Wan,Jiayi Fu,Runze Pan,Xintian Wang,Dionisios G. Vlachos
Heteroatoms-doped carbon materials have recently emerged as effective catalysts for various chemical and electrochemical reactions. The free of metals especially noble metals reduces cost and eliminates issues like sintering or leaching of metals at elevated temperatures in solvents. In this work, selective hydrodeoxygenation (HDO) of 5-hydroxymethylfurfural (HMF) to 2,5-dimethylfuran (DMF) is for the first time achieved over simple nitrogen-doped carbon (N-C) catalysts. At optimal reaction conditions, a 91% yield of DMF is obtained with excellent catalyst stability. Extensive characterization, including extended X-ray absorption fine-structure (EXAFS) and soft X-ray absorption spectroscopy (sXAS), model reactions, basic data science analysis, and DFT calculations suggest that ppm of Fe in particular FeN 3 sites formed in pyrolysis, rather than non-metallic elements, drive key steps such as H 2 activation and deoxygenation of –OH during HMF HDO.
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
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