MATERIALS CHEMISTRY AND PHYSICS
·
2023
·
IF 4.6
Yun Liu,Yueyue Rui,Bingyan Yu,Lihu Fu,Gang Lu,Jie Liu
Negative air ions are becoming increasingly popular as they purify the air by adsorbing dust and hazardous substances, which are beneficial to people's health. The ternary composites of tourmaline and monazite with graphene, germanium , cerium oxide , lanthanum oxide, and titanium oxide were prepared by the ball milling process, and the release of negative oxygen ions was investigated. The enhanced mechanism of tourmaline is analyzed systematically by hysteresis loop with monazite and other substances. The results indicate that monazite relies on its thorium element to generate radioactive energy to excite negative ions . It was discovered that the T/10%M/15%CeO 2 composites exhibited the optimum negative ion release performance of 6580 ions/cm 3 , which is approximately 5–6 times compared to tourmaline. The results of conductivity and hysteresis loop tests demonstrate that tourmaline stimulates negative oxygen ions due to its spontaneous polarization effect and the formation of a polarized electric field. The spontaneous polarization effect of tourmaline is positively correlated with the release amount of negative oxygen ions.
研究领域:
材料科学
·
环境科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2023
·
IF 4.8
Yan Wang,Donghui Wang,Longhua Xu,Kai Xue,Xi Zhang,Xinzhang Shi,Chang Liu,Jinping Meng
Hydroxamic acid collectors display excellent selectivity but poor collecting ability in bastnaesite flotation . Improving the collecting capacity of hydroxamic acid collector appropriately become an effective method to enhance the performance of flotation reagents. A novel oleate hydroxamic acid (OLHA) as a collector was synthesized and applied to bastnaesite flotation in this work. The structure of OLHA was characterized by Fourier transform infrared spectrometry (FTIR) and nuclear magnetic resonance spectroscopy (NMR). The single mineral and artificial mixed minerals flotation experiments results show that OLHA achieved efficient flotation separation of bastnaesite and barite when odium hexametaphosphate (SHMP) was used as depressant. The contact angle, zeta potential, FTIR and X-ray Photoelectron Spectroscopy (XPS) measurements were performed to investigate the adsorption mechanism of OLHA. The contact angle results show that OLHA significantly improved the surface hydrophobicity of bastnaesite. Zeta potential and FTIR results show that in the presence of SHMP, OLHA selectively adsorbs to the surface of bastnaesite. Over all, OLHA adsorbs on the surface of bastnaesite through chemically adsorption, and strengthen the hydrophobicity of bastnaesite surface. Therefore, OLHA is a promising collector for bastnaesite flotation.
研究领域:
矿物加工工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Xiaofeng Zhao,Weipeng Wang,Yuancheng Teng,Yuxiang Li,Xue Ma,Yang Liu,Rajeev Ahuja,Wei Luo,Zhengjun Zhang
Rhabdophane is an important permeable reactive barrier to enrich radionuclides from groundwater and has been envisaged to host radionuclides in the backend of the nuclear fuel cycle. However, understanding of how An4+ and Sr2+ precipitate into rhabdophane by wet chemistry has not been resolved. In this work, Th4+ and Sr2+ incorporation in the rhabdophane/monazite structure as La1–2xSrxThxPO4·nH2O solid solutions is successfully achieved in the acid solution at 90 °C. Some specific issues such as lattice occupation of Th4+ and Sr2+, precipitation reaction kinetics, and crystal growth affected by starting stoichiometry are discussed in detail, along with investigating the chemical stability of La1–2xSrxThxPO4·nH2O precipitations and associated La1–2xSrxThxPO4 monazite. The results reveal that the excess of Sr2+ appears to be a prevailing factor with a suggested initial Sr: Th ≥ 2 to obtain the stability domain of La1–2xSrxThxPO4·nH2O (x = 0∼ 0.1). A rapid ion removal associated with a nucleation process has been observed within 8 h, and Th4+ can be removed more than 98% after 24 h in 0.01 mol/L solutions. From structural energetics based on density functional theory, the lattice occupation of Th4+ and Sr2+ is energetically favorable in nonhydrated lattice sites of [LaO8], although two-thirds of lattice sites are associated with [LaO8·H2O] hydrated sites. Intriguingly, the crystal transformation from rhabdophane to monazite associated with the transformation from [SrO8] to [SrO9] polyhedra can greatly improve the leaching stability of Sr2+.
研究领域:
核化学与放射化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PROGRESS IN NUCLEAR ENERGY
·
2016
·
IF 1.184
Cheng Meng,Xingeng Ding,Junchuan Zhao,Wenqi Li,Chunrong Ren,Hui Yang
Monazites are of considerable interest for immobilization of minor actinides . In this work, the Gd 1-x Ce x PO 4 (0 ≤ x ≤ 1) series is synthesized via conventional solid–state reaction using Ce as the surrogate for minor actinide americium (Am), with microstructure/phase structure characterized by XRD , HRTEM, μ-Raman, and SEM as well. The optimized temperature for preparation of monazite-type Gd 0.4 Ce 0.6 PO 4 solid solution is more than 1300 °C. At 1400 °C, the GdPO 4 ceramic is essentially monazite with little metastable xenotime phase. The metastable xenotime (GdPO 4 ) to monazite transformation occurs during the immobilizing phase of Ce element. The formation of monazite-type Gd 1-x Ce x PO 4 solid solutions in the range 0.1 ≤ x ≤ 1 is confirmed by the Rietveld refinement and Raman spectra . The change of Ce content has no significant influence on the morphology of the monazite-type Gd 1-x Ce x PO 4 compounds.
研究领域:
材料科学
·
核废料管理
·
陶瓷
·
固体化学
✓ 已验证
产品关联
DOI
高影响因子
Minerals
·
2024
·Vol. 14
·期 9
·870
·
IF 2.2
Jieliang Wang,Wenda Lu,Zhao Cao,Xu Wu,Peng Wang,Xiaoping Wang,Wenli Liu
The surface properties of bastnaesite and parisite are similar to their associated gangue mineral, fluorite, which makes the flotation separation of these two rare earth minerals from fluorite one of the industry’s most significant challenges. This study systematically investigates the inhibitory effects and mechanisms of sodium silicate (SS) on bastnaesite, parisite, and fluorite in an octyl hydroxamic acid (OHA) collector system through flotation experiments, various modern analytical methods, and DFT simulations. The flotation test results indicate that the inhibition effects of SS on the three minerals are in the order: fluorite > parisite > bastnaesite. Detection and analysis results indicate that SS forms hydrophilic complexes with Ca atoms on the surfaces of fluorite and parisite, enhancing surface hydrophilicity and inhibiting OHA adsorption, but its impact on bastnaesite is relatively minor. DFT simulation results show that OHA forms covalent bonds with metal ions on mineral surfaces, favoring five-membered hydroxamic-(O-O)-Ce/Ca complexes, and reacts more strongly with Ce atoms than Ca atoms. SS primarily forms covalent bonds with metal atoms on mineral surfaces via the SiO(OH)3−component, and OHA and SS compete for adsorption on the mineral surfaces. OHA has a stronger affinity for bastnaesite, whereas SS shows the highest affinity for fluorite, followed by parisite, and the weakest affinity for bastnaesite.
研究领域:
矿物加工工程
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2024
·
IF 5.2
Weiwei Wang,Zhengyao Li,Erdou Li,Weiyao Zhu,Shaochun Hou,Yuanyuan Wang
Heavy rare earth elements (HREEs) have extensive applications in critical industries. Xenotime (YPO 4 ) is an important phosphatic mineral rich in HREEs. The application of 2-hydroxy-3-naphthyl hydroxamic acid (NHA) as a collector in the flotation of xenotime has rarely been been explored previously. This study reveals the effect of NHA on the flotation behavior and adsorption mechanism of xenotime. The high-grade rare earth concentrate with significant recovery is achieved at the optimized flotation conditions. Techniques such as Fourier transform-infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS), and first-principles calculations were employed to clarify the adsorption mechanism of NHA on xenotime. These studies disclose that chemical adsorption occurs through the interaction between N-bonded and carbonyl O atoms, creating a bidentate bond with an Y 3+ ion on the xenotime surface. These findings underscore the potential of NHA for selective flotation of xenotime, providing valuable insight into xenotime processing.
研究领域:
矿物加工工程
·
材料科学与工程
·
理论化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Peixiong Zhang,Enhui Wang,Chunyu Guo,Tao Yang,Xinmei Hou
High-entropy rare earth phosphates (HE REPO 4 , RE = Ho, Tm, Yb, Lu, Dy, Er and Y) with xenotime structure have been successfully synthesized and comprehensively characterized to evaluate their feasibility as thermal/environmental barrier coatings (T/EBCs) applied in SiC f /SiC ceramic matrix composites (SiC-CMCs). HE REPO 4 show good chemical compatibility with SiO 2 at 1400 °C and excellent high-temperature stability up to 1750 °C. The thermal expansion coefficient (TEC) of HE (6RE 1/6 )PO 4 is 5.9 × 10 −6 /°C ranging from room temperature to 900 °C, which is close to that of SiC-CMCs. Compared with single-component REPO 4 , the thermal conductivity of HE (6RE 1/6 )PO 4 (from 5.1 W·m −1 ·K −1 at 100 °C to 2.8 W·m −1 ·K −1 at 1300 °C) is significantly reduced benefiting from larger lattice distortion. These allow HE REPO 4 to be a potential candidate as T/EBCs applied in SiC-CMCs.
研究领域:
材料科学
·
陶瓷
·
涂层
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 9
·6366-6377
·
IF 2.993
Li Wenqi,Ding Xingeng,Meng Cheng,Ren Chunrong,Wu Huating,Yang Hui
Rare earth phosphates (REPO 4 ) are considered as promising materials to immobilize the high-level radioactive waste. In the paper, Gd 1− x Yb x PO 4 ( x = 0, 0.1, 0.2, 0.4, 0.6, 0.8 and 1.0) series were prepared via the solid-state reaction using Gd as the surrogate for minor actinide Am and Cm, and the structure, phase transformation and morphology were characterized by XRD, Raman, TEM and SEM. With the calcination temperature ranging from 1200 to 1500 °C, the coexisted phases of monazite- and xenotime-type structure are observed in Gd 0.9 Yb 0.1 PO 4 . The monophasic xenotime-type Gd 0.9 Yb 0.1 PO 4 is obtained at 1600 °C. The monazite → xenotime transformation of Gd 1− x Yb x PO 4 depends on the substitution of Gd 3+ by Yb 3+ ions. With the decrease in Gd 3+ content, the gradual changes of FWHM and the hypsochromic shift of P-O symmetrical stretching vibration (Vs) are observed in the Raman spectra, indicating that the distortion of PO 4 tetrahedra occurs during the phase transformation process. The chemical durability test is measured by the ASTM product consistency test leaching method, and the normalized mass loss (NL Gd ) of Gd and (NL Yb ) of Yb is extremely low and shown in the order of 10 −6 –10 −7 g/m 2 for all the ceramics.
研究领域:
材料科学
·
核废料管理
·
固态化学
·
辐射化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）