SEPARATION AND PURIFICATION TECHNOLOGY
·
2025
·
IF 9
Junyi Xiang,Xi Lu,Hongru Rao,Luwei Bai,Qingyun Huang,Xuewei Lv
The separation of vanadium and chromium from vanadium-chromium slag constitutes the greatest bottleneck in the exploitation and utilization of high-chromium vanadium-titanium magnetite, which mainly results from the insufficient understanding of the behavior of similar elements vanadium and chromium during the extraction process. In this research, a series of spinels FeV x Cr 2- x O 4 (0 ≤ x ≤ 2) were synthesized via the high-temperature solid-state method, and their sodium roasting and leaching behavior were comprehensively analyzed. The transformation rules of sodium vanadate and chromate were investigated by XRD, SEM-EDS, FTIR, and thermodynamic calculation. The results indicate that in the FeV x Cr 2- x O 4 (0 ≤ x ≤ 2) − Na 2 CO 3 system, at 300°C, a portion of chromium spinel phase is preferentially and slowly oxidized to Cr 2 O 3 , while the vanadium spinel rapidly oxidizes to form NaVO 3 at 400°C. Above 500°C, NaVO 3 further reacts with Na 2 CO 3 to form Na 4 V 2 O 7 , and Na 2 CrO 4 also begins to form concurrently. As the proportion of Cr in FeV x Cr 2- x O 4 increases, both the leaching efficiencies of vanadium and chromium from the sodium-roasted samples decrease, with the leaching efficiency of chromium decreasing more significantly. Significant competitive and synergistic effects between vanadium and chromium are observed in the roasting of FeV x Cr 2- x O 4 with Na 2 CO 3 . This study is expected to provide theoretical support for the development of efficient vanadium-chromium extraction processes.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ENVIRONMENTAL MANAGEMENT
·
2024
·
IF 8
Shengjian Zhao,Hualong Yang,Xuehui Liu,Siqi Ma,Peigang He,Zhenlin Sun,Dechang Jia,Paolo Colombo,Yu Zhou
Metakaolin-based geopolymers are very promising materials for improving the safety of low and intermediate level radioactive waste disposal, with respect to ordinary Portland cement , due to their excellent immobilization performance for Cs + and superior chemical stability. However, their application is limited by the fact that the leaching behavior of Cs + is susceptible to the presence of other ions in the environment. Here, we propose a way to modify a geopolymer using perfluorodecyltriethoxysilane (PDFS), successfully reducing the leaching rate of Cs + in the presence of multiple competitive cations due to blocking the diffusion of water. The leachability index of the modified samples in deionized water and highly concentrated saline water reached 11.0 and 8.0, respectively. The reaction mechanism between PDFS and geopolymers was systematically investigated by characterizing the microstructure and chemical bonding of the material. This work provides a facile and successful approach to improve the immobilization of Cs ions by geopolymers in real complex environments, and it could be extended to further improve the reliability of geopolymers used in a range of applications.
研究领域:
材料科学
·
放射性废物管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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
Journal of Cleaner Production
·
2025
·
IF 10
Jialin Chen,Jingfei Zhou,Shoukai Chen,Haibo Shi,Qingfeng Hu,Yingdong Tang
It is anticipated that this would address the underlying reasons of the disposal challenges and associated safety hazards if Cr-containing tannery waste from the tannery industry could be produced into stabilized sustainable construction materials. In this paper, the geopolymer was prepared employing solid waste furnace slag (FS) and tannery sludge powder (TSP) and evaluated for mass loss rate, appearance, residual compressive strength, pore properties, phase transformation and Cr leaching behavior after different thermal exposure (200 °C, 400 °C, 600 °C, 800 °C, and 1000 °C) for 2 h. The results revealed that the compressive strength increased and then dropped with increasing thermal exposure temperature, with the residual compressive strength of geopolymer being the maximum (63.00 MPa) at 200 °C. Dehydroxylation and phase transition disrupted the pore structure, and the hydration products, mostly C-(A)-S-H, underwent depolymerization and repolymerization to create new crystalline phases including akermanite and gehlenite. Even at 600 °C, which has the greatest impact on the safety of geopolymers, the leaching concentrations of total Cr and Cr (Ⅵ) were only 1.39 mg/L and 0.074 mg/L, respectively, which were still far below the standard requirements. The possible Stabilization-Migration-Restabilization (SMR) route of Cr was identified as follows: Cr was physically encapsulated by C-(A)-S-H at 20 °C–400 °C; C-(A)-S-H was destroyed at 600 °C–800 °C, and Cr migrated and was oxidized to Cr (Ⅵ) by CaO; it was then probably reduced to Cr(V) by heat and Mg-O at 1000 °C and finally immobilized in akermanite by chemical bonding.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Xiaoao Shi,Hao Rong,Jinping Li,Yifan Zhao,Lu Ren,Si Chen,Jingxin Liu,Meng Mei,Yongjie Xue,Teng Wang
Whether the presence of microplastics (MPs) affects the clean incineration of dyeing sludge (DS), especially focusing on the leaching behavior of Cu and Zn from their incineration bottom ashes (BAs), has become an emerging issue. This study tries to explore the effects of typical polyethylene terephthalate (PET) and polyvinyl chloride (PVC) MPs on leaching behavior of Cu and Zn in BAs, and reveal its inner mechanism. Results showed the presence of MPs raised the leaching rate, namely, both MPs accelerated the leaching of Cu and Zn, which eliminated the risk to human health and to the environment. The regulating mechanism to the Cu and Zn leaching behavior in DS-MPs BAs could be attributed to their amorphous structure. It included: (1) Under low MPs content, Cl and polarity actions derived from MPs destroyed the amorphous structure and promoted Cu and Zn leaching. (2) Under high MPs content, the generation of the amorphous Si/Al structure relieved the Cu and Zn leaching, where Cu and Zn were tightly bonded to [SiO 4 ] or [AlO 4 ] and existed stably in BAs. Despite 30% MPs could relief the release of HMs to a certain extent, the existence of MPs still aggravated the HMs threat of DS BA in actual scene.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Hongru Jin,Chong Wei,Haozhen Li,Xiaoqiang Li
Internal crystallization is a significant process in the preparation of glass-ceramics (GCs). The glass phase is one of the important factors affecting the internal crystallization process within GCs. In this study, Gd 2 Ti 2 O 7 pyrochlore GCs with different borosilicate glass systems were prepared via an oxide route and consolidated via a cold-pressing and sintering process to be used as waste forms for actinide immobilization. After sintering at 1250°C, it was confirmed that the pyrochlore phase (Gd 2 Ti 2 O 7 ) was the major immobilization phase, while the apatite phase (Gd 9.33 (SiO 4 ) 6 O 2 ) was a minor phase. The influence of glass composition on the minor phase formation and pyrochlore grain growth was also investigated. The content of the minor phase (Gd 9.33 (SiO 4 ) 6 O 2 ) in GCs showed a positive correlation with the content of non-bridging oxygen (NBO) in the glass systems. Meanwhile, the average grain size of the pyrochlore phase also exhibited a positive correlation with the NBO content, highlighting the influence of glass composition on the grain growth process. In addition, static leaching tests confirmed that all GCs exhibited high chemical durability with normalized Gd and Ti leach rates ranging from ∼10 -4 -10 -5 g m -2 d -1 after 28 days. However, preferential leaching of the glass phase was observed in GCs during the leaching tests. Glasses with higher NBO content exhibited more severe alterations from leaching, evidenced by significantly higher leach rates of glass-forming elements such as Si and B. Surface analysis revealed that the GCs surface experienced breakage and peeling, with damage on the glass phase ranging from ∼200 nm to 700 nm.
研究领域:
材料科学
·
核废料管理
✓ 已验证
DOI
高影响因子
Minerals
·
2024
·Vol. 14
·期 4
·352
·
IF 2.2
Zujiang Pan,Cuo Jian,Zaihua Peng,Xinzhuang Fu,Rui He,Tong Yue,Wei Sun
The Yulong copper deposit in Tibet is a typical porphyry copper deposit, with about 30 million tons of copper oxide ore in the surface layer. However, more than 40% of the copper resources are in a combination state, resulting in an extraction efficiency of only 50% for copper via the hydrometallurgical process. In this study, the process mineralogy of the combined copper oxide ore was systematically investigated and a calcium fluoride-enhanced leaching process is proposed to increase the leaching efficiency of the combined copper ore. The process mineralogy of the combined copper oxide ore was analyzed using various testing techniques, including chemical analysis, X-ray diffraction, and a process mineralogy parameter testing system (Mineral Liberation Analysis). The results revealed that limonite accounted for 86.12% of the sample, and 63.51% of the copper resource existed in the form of combined copper oxide in limonite. However, it is difficult for the uniformly distributed combined copper oxide in limonite to sufficiently make contact with sulfuric acid, which is the leaching agent, resulting in low copper leaching efficiency. The enhanced leaching behavior of the combined copper oxide ores was also investigated, thereby determining effective and economical enhanced leaching conditions. Under optimal conditions, at a grinding fineness ratio of −0.074 mm (accounting for 85%), liquid-solid ratio of 4:1, sulfuric acid concentration of 50 g/L, temperature of 30 °C, CaF2dosage of 1% of the ore mass, and leaching time of 4 h, the copper leaching efficiency increased to 60.57%, which was 7.34% higher than that of atmospheric pressure leaching. Finally, the enhanced leaching slag was analyzed using an electron probe microanalyzer. It indicated that fluorine ions can erode the combined copper oxide ore and facilitate the diffusion of hydrogen ions inside the limonite, thereby achieving a strengthening effect.
研究领域:
冶金学
·
矿物学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2021
·Vol. 105
·期 2
·1459-1471
·
IF 3.784
Shengtai Zhang,Baoliang Xu,Jingkai Cheng,Shilin Luo,Yi Ding,Shiyin Ji,Tao Duan,Jianjun Ma,Cairong Jiang
Molten salt provides a fast mass transfer and nucleation process, so the ceramic solid solution for immobilization of high-level nuclear waste (HLW) can be synthesized at lower temperatures. The chemical stability in the process of interaction with groundwater determines the ability of the matrix phase to prevent radionuclides from entering the biosphere. Nd-doped Y 3 Fe 5 O 12 ceramics were prepared by the molten salt method at different sintering temperatures (1000℃, 1100℃, 1200℃) and different m (eutectic salt): m (oxide) ratios (2:1, 3:1, 4:1). The sintered ceramic is Y 3-x Nd x Fe 5 O 12 , where x is the solubility of Nd in YIG. The results show that the optimum mass ratio of molten salt to oxide is 3:1. The solubility of Nd in garnet is 33.3 mol% ( x = 1.1) and 56.7 mol% ( x = 1.6) at 1100℃ and 1200℃, respectively. In the neutral medium, Nd does not transfer to the liquid phase. Acid leaching promotes the strong dissolution of the garnet matrix. In this case, the leaching rate of Nd from ceramics to the liquid phase is two to three orders of magnitude higher than that in a neutral medium. The experimental results suggest that garnet matrices can reliably immobilize actinides in subsurface repositories.
研究领域:
材料科学
·
核废料管理
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Zixu Chen,Peigang He,Wanlin Li,Shengjian Zhao,Dechang Jia,Paolo Colombo,Yu Zhou
Geopolymers with zeolite-like structures can effectively immobilize radioactive ions through their three-dimensional cage-like framework. This study investigated the synthesis of geopolymers via cold reaction sintering using metakaolin, anhydrous and nonahydrate sodium metasilicate for Cs + immobilization. Optimizing the Si/Al molar ratio to 1.5:1 and water content to 20 wt% yielded the best mechanical properties and near-complete reaction. The transient liquid phase formed by the dehydration of sodium metasilicate nonahydrate facilitated densification. CsCl incorporation resulted in a predominantly amorphous phase with the formation of NaCl crystals. Toxicity leaching tests demonstrated Cs + immobilization rate exceeding 91 % for CsCl content below 12 wt%. Short-term leaching tests confirmed low leaching rates (< 4 × 10⁻³ cm/day after 4 days), and leachability indices well above the typically required value of 6 for cement-based matrices. These results establish the viability of cold reaction sintered geopolymers for Cs + immobilization, highlighting their promise for nuclear waste management applications.
研究领域:
材料科学
·
核废物管理
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Lei Yu,Kuibao Zhang,Kui Liu,Baozhu Luo
In this study, the chemical durability of Gd 2 Zr 2 O 7 transparent ceramics was investigated under different pH environments. The influence of acidic and alkaline environments on the leaching behavior of Gd 2 Zr 2 O 7 immobilization matrix were studied to simulate the disposal of nuclear waste forms in deep geological landfills. The measured results demonstrate that the normalized leaching rates in acidic environments are higher than those in alkaline and neutral environments. The macroscopic color of all samples fades after leaching, and the visible range in-line transmittance of the leached transparent ceramics decreases slightly at pH ≤ 9. The leaching behavior leads decrement of lattice volume and increment of surface roughness, but it exhibits no significant effect on the surface elemental distribution. Never the less, Gd 2 Zr 2 O 7 transparent ceramic exhibits excellent chemical durability in weak alkaline environment, and the leaching process leads to the discoloration of Gd 2 Zr 2 O 7 transparency.
研究领域:
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Wenlong Zhang,Weixue Wang,Zhimin Yao,Tengyue Zhang,Huifeng Jiao,Hongjie Wang
Extensive research has been conducted on the leaching behavior and risks of the leachate of tire wear particles (TWPs) in aquatic environments. However, the leaching-driven transformations of TWPs and the subsequent environmental impacts have been largely overlooked. This work examines the changes in physicochemical properties of TWPs during leaching in several water bodies, thereby facilitating a more thorough assessment of the environmental impacts. The results revealed that the environmental behavior related properties of TWPs, including surface morphology, pores, contact angel, zeta potential, functional groups, and surface adsorption sites varied at different levels during leaching. The ionic strength and organic matter content of water body highly determine the above transformations. The carbon index (CI) and O/C ratio of TWPs increased by 55.40 % and 14.27 % after leached in the water for 30 days, while the adsorption capacity of the TWPs for tetracycline (TC) and oxytetracycline (OTC) decreased by 27 % and 24.63 %, respectively. Herein, the changes in the functional groups and polarity during leaching highly influenced the adsorption performance of leached-TWPs. This study provides novel insight into understanding the leaching behavior of TWPs in aquatic environments and highlights an urgent need to assess the environmental implications of leaching-driven transformations of TWPs.
研究领域:
环境科学
·
水污染控制
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2021
·Vol. 29
·期 8
·11267-11280
·
IF 4.223
Yang Renhe,He Tingshu
High-fluorine alkali-free liquid accelerator (AF -hf , F − concentration was about 2.31g/L) was still used in engineering because of its low cost, excellent stability, and coagulation-promoting effect. The main purpose of this study was to explore the leaching behavior of fluorine ions in shotcrete for tunnel lining with high-fluorine alkali-free liquid accelerator and whether there was fluoride pollution. The setting time and mechanical properties of cement paste and mortar with AF -hf were tested. Under different environmental conditions, F − leaching concentration from sprayed concrete was studied comparatively. Moreover, XRD and SEM were used to analyze the crystal composition and micro morphology of hydration products. The experimental results showed that with the increase of AF -hf dosage, the setting time of cement paste was greatly shortened, and later strength of mortar and shotcrete could meet the construction requirements. In addition, when the leaching solution type (including Na 2 CO 3 , Na 3 PO 4 , Na 2 SO 4 , and NaNO 3 ) and testing conditions (particle size, soaking temperature, leaching solutions) were different, F − leaching concentration changed regularly, and the minimum value was more than 20 mg/L, which might cause fluorine pollution to groundwater and soil. After shotcrete samples were soaked, the CaF 2 peaks’ intensity was relatively weaker and Ca(OH) 2 decreased obviously. Meanwhile, cement hydration products became looser and abundant of flaky C-S-H gel transformed into fibrous and chained structure.
研究领域:
土木工程
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）