HYDROMETALLURGY
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2020
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IF 3.338
Jia Lipan,Zhao Zhongwei,Liu Xuheng,He Lihua
Selective precipitation is the main process used to remove molybdenum from tungstate solutions by the tungsten industry in China. The process exploits the fact that molybdenum is a sulfophile whereas tungsten is an oxyphile. First, the sulfur ions replace oxygen and convert the molybdate to thiomolybdate, then a moderate amount of additives (copper compounds) are reacted with the thiomolybdate to form complex precipitates. We call the filtered wet precipitate “molybdenum-removal sludge”. The main components of the sludge are molybdenum, copper and sulfur, infiltrated by some amount of tungsten due tomechanical entrainment. Based on the fact that copper is a typical sulfophile, it is possible that copper ions can react withthe sulfur of the thiomolybdate, thus converting it to soluble molybdate. This is actually the reverse of molybdenum sulfuration process, so we therefore call it the “reverse sulfuration process.” Based on the leaching thermodynamics and structure characteristics of this kind of sludge, a new treatment process was developed in this work. About 90% of tungsten and 15% of molybdenum were washed out with ammonia water when the pH > 9. The recovery rate of molybdenum was close to 70% when a stoichiometric amount of copper ions (with sodium hydroxide 4 mol/L) were utilized for the reverse sulfurization leaching. The leaching rate of molybdenum obtained on leaching with 2 mol/L sodium hydroxide for 120 min at 80 °C and then fixing with copper chloride was 94.4%, and 87.67% of sulfur ions were fixed in the form of an amorphous Cu S compound.
研究领域:
冶金学
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环境科学
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DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2024
·Vol. 55
·期 6
·5221-5234
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IF 2.4
Sun Hu,You Mengyu,Hou Yanrui,Luo Jun,Rao Mingjun,Han Guihong,Li Guanghui
The mainstream oxidative roasting method is facing challenges in processing low-grade molybdenite (MoS 2 ) concentrates, calling for deep understandings toward the behaviors of impurities. This study took pure minerals and reagents as the objects and conducted elaborate experiments and theoretical calculations into the formations of molybdates and their influences on MoS 2 oxidation. The emphasis are on the reactions under local O 2 -absent conditions and the sintering of MoS 2 caused by molybdates of Ca, Fe, Cu, or Pb. It was found that molybdates could directly form from MoO 2 or MoS 2 without O 2 at 600 °C to 650 °C, due to the promotion of reactivity and reducibility of MoO 2 when combining with impurity metals. The produced molybdates would lower the melting point, dissolve in liquid MoO 3 , and migrate to oxidation interface to form a sintering layer that inhibits O 2 diffusion. Overall, this study has discovered new pathways of molybdates formation and new effects of segregation on the sintering and established evolution patterns of bulk MoS 2 concentrate during roasting, which may be significant complements to the fundamentals of classical molybdenum metallurgy.
研究领域:
冶金学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Xuheng Liu,Zhigang Cao,Xingyu Chen,Jiangtao Li,Lihua He,Fenglong Sun,Zhongwei Zhao
The presence of iron (Fe) and copper (Cu) negatively impacts molybdenum (Mo) recoveries in existing metallurgical processes. This study investigated the speciation of Mo in highly acidic solutions, exploring the removal of Fe and Cu from low-grade molybdenum calcine through acid washing. The species distribution diagram for the Mo-H 2 O system indicated that Mo predominantly existed as a monomeric and dimeric species at pH < 0. Acid washing experiment results indicated that 92 % of Fe and 97 % of Cu were removed, and the Mo loss rate remained <4 %. Furthermore, optimized conditions included 3 M H 2 SO 4 , 150 min, 90 °C, and a liquid–solid ratio of 2:1. Characterization through X-ray diffraction (XRD) and scanning electron microscopy- energy dispersion spectrum (SEM-EDS) analysis of the acid washing residue indicated that Mo existed in the form of MoO 3 . Furthermore, solvent extraction successfully recovered over 97 % of Mo from the acid washing solution. Recycling the raffinate into the acid washing process was found to reduce overall process costs. This study offered a practical and economical approach, optimizing the utilization of Mo resources by addressing challenges associated with Fe and Cu contents in existing processes.
研究领域:
冶金学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
JOM
·
2025
·
IF 2.3
Che Wenfang,Deng Rongdong,Xiao Shijie,Zhang Jing,Wu Siyuan,Jiao Fen
To address the challenges associated with the agglomeration and encapsulation of chalcopyrite by molybdenite in flotation slurries, which hinder the effective separation of copper and molybdenum, this study investigated the effects of various dispersants on the dispersion behavior of chalcopyrite and molybdenite, along with the underlying mechanisms. Optical microscopy, focused beam reflectance measurements (FBRM), infrared spectroscopy, zeta potential analysis, and other analytical techniques were employed. The results revealed that the dispersion behaviors of chalcopyrite and molybdenite align with the EDLVO theoretical model. At a slurry pH of 12, the dispersant effectively dispersed molybdenite and minimized its agglomeration around chalcopyrite. The dispersive capabilities of the tested dispersants followed the order: sodium carbonate (Na 2 CO 3 ) > sodium hexametaphosphate (SHMP, (NaPO 3 ) 6 ) > sodium silicate (Na 2 O·nSiO 2 ) > ammonium bicarbonate (NH 4 HCO 3 ). Specifically, carbonate ions produced by the hydrolysis of Na2CO3 were chemically adsorbed onto the molybdenite surface, while hexametaphosphate primarily adhered through physical adsorption. This adsorption enhanced the dispersion of molybdenite particles by increasing electrostatic repulsion between them. Mixed ore flotation experiments demonstrated that both Na 2 CO 3 and SHMP significantly reduced the copper grade in the molybdenum concentrate, from 3.95% to 2.69% and 2.67%, respectively.
研究领域:
矿物加工工程
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Tingting Liu,Heng Liu,Xiuju Wu,Yanli Niu,Bomin Feng,Wei Li,Weihua Hu,Chang Ming Li
Molybdenum (Mo) based materials including its phosphides, carbides, nitrides , oxides, dichalcogenides and metallic alloys have received particular interest in recent years for sustainable hydrogen evolution reaction (HER) electrocatalysis . In this study, a novel Mo 2 C/MoP hybrid nanoparticle embedded N, P co-doped carbon nanofibers on carbon fiber paper (Mo 2 C-MoP NPC/CFP-800) is successfully prepared as a highly efficient hierarchical HER electrocatalyst . Benefitting from its structural advantages and compositional merits, this Mo 2 C-MoP NPC/CFP-800 electrocatalyst displays remarkable catalytic activity as well as excellent durability for HER. Only 85 and 146 mV overpotential is required to drive a HER current density of 10 mA cm −2 in acidic and alkaline solution, respectively. Remarkably, this electrocatalyst is also able to fulfill efficient HER even in seawater . Further, this work reveals that the Mo 2 C/MoP hybrid nanoparticle is superior to MoP nanoparticle under present system in HER electrocatalysis, which may offer valuable clues on further design and synthesis of HER electrocatalysts.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
Materials Today Communications
·
2023
·
IF 3.8
Yuhui Chen,Ruihua Zhang,Zhenhua Hao,Yongchun Shu,Jilin He
In this study, MoO 2 was reduced by an unmixed carbon reduction method. Effects of reduction temperature, reduction time and distance between carbon and MoO 2 on the phase composition of reduction products were investigated. Results show that the phase change during the reduction process are MoO 2 →Mo 2 C→Mo with the increase of temperature. The reduced product is Mo 2 C when reduction temperature is 1000 °C and 1050 °C. Pure Mo can be obtained when the reduction temperature increases to 1100 °C. The reduced product changed from nearly spherical Mo particles with fine molybdenum dioxide particles attached on surface to polyhedron Mo particles with smooth surface when the distance between carbon and MoO 2 decreases from 10 mm to 1 mm. The reaction showed a similar change with the changes of the reaction time. The difference is that there will be residual Mo 2 C in reduced product when reduction time was 1 h. This method of carbon reduction can provide low carbon concentration by controlling the carbon distance to avoid the existence of molybdenum carbide in the product of molybdenum preparation.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2020
·
IF 3.795
Hai Yan,Bingqiao Yang,Mengyuan Zeng,Pengliang Huang,Aiping Teng
Molybdenite and chalcopyrite is generally separated through the selective depression of chalcopyrite using potentially toxic depressants such as sodium sulfide and cyanides. In this work, xanthan gum (XG), a polymer polysaccharide, was investigated as a potential molybdenite depressant in copper-molybdenum sulfides separation. Single mineral flotation tests indicated that molybdenite could be effectively depressed by XG, while chalcopyrite was slightly affected. The artificial mixed minerals flotation tests proved that molybdenite and chalcopyrite could be selectively separated with the addition of XG. The adsorption mechanism was studied through zeta potential and infrared spectroscopy measurements. The results revealed that XG mainly adsorbed on molybdenite surfaces other than chalcopyrite. In a word, the experiments results illustrated that XG could be applied as a promising depressant in the selective flotation separation of molybdenite and chalcopyrite, which has the advantage of environment compatibility over conventional copper depressants.
研究领域:
矿物加工工程
·
环境科学
✓ 已验证
DOI
高影响因子
FUEL
·
2020
·
IF 5.578
Hao Qu,Sihui He,Yue Su,Yulong Zhang,Haiquan Su
Direct synthesis of ethanol from syngas (a mixture of H 2 and CO) is considered as an eco-friendly and industrially important process to produce renewable fuels and chemicals. The current non-noble metal catalyst systems suffer from either low selectivity or multiple processes with high energy consumption. Here, we report a novel molybdenum diselenide-based catalyst system for high-selective conversion of syngas into ethanol. For a series of K-promoted MoSe 2 catalysts with different K/Mo ratios (K x -MoSe 2 , x = 0.25-1.00), K 1.00 -MoSe 2 surprisingly exhibits excellent ethanol selectivity up to 58.7 C mol % in total alcohols and 31.1 C mol % in the total product, which is higher than the highest selectivity value for the non-noble metal catalysts reported in the literature. The high ethanol selectivity is attributed to the formation of K-Mo-Se active phase and the synergistic effect of the Mo IV , Mo V and Mo VI multivalent species in the active phase. This study opens up a highly selective non-noble metal catalyst system for the direct synthesis of ethanol by syngas, which is of practical significance for the catalytic conversion of hydrogen-poor syngas.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Yang Li,Shouwei Zuo,Qiaohong Li,Huawei Huang,Xin Wu,Jing Zhang,Huabin Zhang,Jian Zhang
Hierarchical structures with a complex interior and a functional exterior are highly advantageous for energy-related electrocatalysis. Herein, a carbon-supported molybdenum carbide/sulfide heterostructure interior is covered with a defect-rich MoS 2 nanosheet exterior. The resulting hierarchical structure (C–MoCS x @MoS 2 ) is a promising nanoreactor for seawater splitting. X-ray absorption spectroscopy demonstrates that MoC and MoS 2 are chemically integrated into the C–MoCS x core, providing abundant C–Mo–S sites for hydrogen evolution. Experimental studies and theoretical calculations show that the defect-rich MoS 2 exterior exhibits a high capability for repelling salt deposition, allowing the penetration of low-saline water into the inner C–MoCS x to accelerate the water-splitting reaction. As expected, the obtained C–MoCS x @MoS 2 is remarkably active and exceptionally stable in natural seawater. This work opens new avenues for developing effective electrocatalysts for seawater splitting and other energy-related applications.
研究领域:
材料科学
·
能源化学
·
表面科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Ruizhuo Liu,Jian Cao,Zhongwei Zhao,Yongli Li
Solvent extraction with organophosphorus extractants has potential as a low-cost method for efficient Mo recovery for acidic leaching solutions. However, improved selectivity is required to obtain high-purity Mo products. In this study, various acidic organophosphorus extractants were compared, and 2-ethylhexylphosphonic acid mono-(2-ethylhexyl) ester (P507) was found to be optimal for efficient Mo extraction and Fe separation from acidic leaching solutions. Under the optimized conditions (40 vol% P507, 3:1 organic/aqueous, 20 °C, 5 min), the Mo and Fe extraction efficiencies reached 98.1 % and 35.2 %, respectively, with a separation factor of 90.1. The Mo/Fe separation efficiency was further improved using a two-stage countercurrent extraction method. The Mo extraction efficiency was attributed to coordination bonds (P = O → Mo) formed between Mo(VI) oxycations and P507 dimers, as well as covalent bonds (P O Mo) formed by substituting the hydrogen ions in P507. Increasing the H 2 SO 4 concentration in the leaching solution gradually transformed MoO 2 2+ into Mo 2 O 5 2+ dimers, which formed MoO 2 (HA 2 ) 2 and Mo 2 O 5 (HA 2 ) 2 metal complexes during the extraction process. HCl scrubbing of the loaded organic phase effectively removed Fe. For subsequent ammonia stripping of the HCl-scrubbed organic phase, the optimal ammonia concentration was 1.25 mol/L. Further increasing the ammonia concentration promoted the saponification reaction of ammonia with P507, thereby reducing the Mo stripping efficiency. In summary, using multistage countercurrent extraction, increasing the H 2 SO 4 concentration in the leaching solution, and scrubbing the loaded organic phase with HCl facilitate efficient Mo/Fe separation, providing a feasible approach for the preparation of high-purity ammonium molybdate with broad application prospects.
研究领域:
冶金化学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2025
·
IF 8.2
Rui Jiang,Bowen Deng,Huijun Liu,Wen Lei,Liu Pi,Liangyou Hu,Xuhui Mao,Xinyu Li,Yaxu Wen,Dihua Wang
A facile synthesis process that facilitates the industrial-scale production of catalysts is the prerequisite of the hydrogen evolution reaction (HER) industry. Molybdenum-based catalysts are ideal alternatives for precious-metal-based HER materials; however, they remain challenging in scale-up preparation due to the costly and complex Mo sources. Herein, we propose a molten salt paired electrolysis approach to synthesize transition-metal-doped Mo2C catalysts directly from molybdenite (mainly consisting of micrometer-scale MoS2 bulks), an earth-abundant natural Mo ore. Unlike Fe-doped Mo2C in which those transition metal dopants are inclined to diffuse into inner planes of Mo2C, this unique synthesis approach leverages the differences in transition metal diffusion energy barriers, ultimately leading to the development of Ni-doped Mo2C catalytic materials with specific Ni-enriched interfaces. Owing to the unique design and structures of the catalyst, the interfacially Ni-enriched Ni-doped Mo2C exhibited promising HER performance and long-term stability. Very interestingly, MoS2 nanoflakes, as side products, can be collected at the anode side while interfacially Ni-enriched Mo2C was concurrently obtained at the cathode side during the electrolytic synthesis process. This work not only deepens our knowledge on constructing active-site-enriched interfaces that are beneficial to HER but also gives clues to upcycling raw materials.
研究领域:
材料科学
·
电化学
·
能源催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
HYDROMETALLURGY
·
2021
·
IF 4.156
Yubiao Li,Qihang Xiao,Zhiming Li,Andrea R. Gerson
The slow leaching rate of molybdenite (MoS 2 ), due to its inert nature, and low recovery hinders the application of traditional hydrometallurgical processing. This study investigated the effects of grinding speed and time, molar ratio of sodium chlorate (NaClO 3 , oxidant) to MoS 2 , leaching time and temperature on the leaching efficiency of molybdenum (Mo). Grinding at low speeds via mechanical activation decreased particle size. However, at speeds over 450 rpm for 1.0 h, or at lower speeds but with longer time, it triggers a solid-state reaction (mechanochemistry) producing soluble Na 2 Mo 2 O 7 . This may be due to the existence of an energy threshold for the solid-state reaction. The most suitable activating conditions were 600 rpm for 0.5 h, with a molar ratio of NaClO 3 : MoS 2 = 5, leached in 0.1 M NaOH solution for 2.0 h at 348 K, giving rise to a Mo recovery of 74.8%. The initial acid leaching stage of the ground mixture is dominated by the dissolution of Na 2 Mo 2 O 7 , giving rise to elevated Mo recovery. The later stage is controlled by the dissolution of MoS 2 , slowing down the increase in Mo extraction. As compared to alkaline conditions, acidic leaching of MoS 2 ground at low speeds (non solid-state reaction) gives greater Mo recovery, due to the greater activity of NaClO 3 to MoS 2 under acidic conditions. However, the greatest Mo recovery is achieved in alkaline solution for MoS 2 ground at high speed (solid-state reaction) due to the occurrence of mechanochemical reaction.
研究领域:
冶金化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）