JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2021
·
IF 6.064
Yuxi Lu,Shuai Wang,Hong Zhong
Wolframite is often associated with calcium bearing minerals, leading to low grade, while conventional anionic collectors are hard to realize their efficient flotation separation, thus the effective structural modification of cationic collectors provides a new insight into enhancing the comprehensive development of wolframite resources. In this study, a surfactant 3-dodecyloxy propyl amidoxime (DOPA) was designed and first used as the collector in flotation separation of wolframite from fluorite and calcite. Computational calculations basically proved the correctness of predictions about the performances of DOPA. Micro-flotation tests indicated that compared to DDA and conventional anionic collector benzohydroxamic acid (BHA), DOPA possessed superior collecting ability to wolframite and excellent selectivity against fluorite and calcite at low concentration, with no frother or activator employed, which is supposed to be an efficient collector for separating wolframite from calcium bearing minerals. The separation mechanisms of DOPA between wolframite and fluorite/calcite were further probed, revealing that besides the electrostatic attraction between DOPA and wolframite, DOPA could chemisorb onto wolframite surfaces by forming five-membered ring toward the surface cation site Fe or Mn, with no significant interaction observed on fluorite/calcite surfaces, resulting to the excellent separation performance.
研究领域:
矿物加工工程
·
材料科学与工程
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DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2019
·
IF 3.372
Jianjun Wang,Wenheng Li,Zihan Zhou,Zhiyong Gao,Yuehua Hu,Wei Sun
Fluorite is usually separated from calcite by froth flotation method using large amounts of sodium silicate depressant, which can cause trouble in the loss of fluorite and wastewater treatment. In this study, green and low-cost 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP or H 4 L) was used as pH-dependent switch to initially depress fluorite for calcite pre-removal at pH 6.0, and then activate fluorite for further upgrading fluorite concentrate at pH 8.0. The depressing behavior and mechanism were reported in this work. H 2 L 2− was the dominant form of HEDP, and a stronger chemical adsorption of H 2 L 2− on fluorite hindered the subsequent adsorption of sodium oleate (NaOL), while that of the calcite showed the opposite result. Two active O atoms in H 2 L 2− could well match in interatom distance with two Ca sites on fluorite to form Ca-H 2 L complexes. The pH-dependent switch reagent reported here may open a new avenue for more selective separation among mixed mineral systems.
研究领域:
矿物加工工程
·
环境科学
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Sara Adeeba Ismail,Lulu Jiang,Peng Zhong,Truls Norby,Donglin Han
La 2 Ce 2 O 7 is known to be a disordered fluorite, i.e., 50% La-doped CeO 2 , exhibiting oxide ion conduction with contributions from protons in wet atmospheres and minority electrons under reducing conditions. Here, we report the effect of additional doping by partial substitution of La 3+ with divalent alkaline earth cations A 2+ ( A = Ca, Sr, Ba) on the hydration behavior and electrical conductivity of La 2 Ce 2 O 7 . A single-phase cubic fluorite structure was obtained for La 2 Ce 2 O 7 , (La 1- x Ca x ) 2 Ce 2 O 7-δ ( x = 0–0.3), (La 1- x Sr x ) 2 Ce 2 O 7-δ ( x = 0–0.2), and (La 1- x Ba x ) 2 Ce 2 O 7-δ ( x = 0–0.05). Substitution by A 2+ enhanced the degree of hydration, which may be attributed to increased concentration of hydratable oxygen vacancies and coordination of oxide ions by A 2+ in addition to La 3+ , while the basicity of the different A 2+ seemed unimportant. The doping increased ionic conductivity slightly, while the n-type electronic conductivity under reducing atmospheres increased considerably. XPS analyses indicated that the concentration and binding energy of Ce 3d electrons decreased with increasing doping level of Ca, implying an enhanced mobility of electrons which may be attributed to an observed decrease in lattice parameter .
研究领域:
材料科学
·
电化学
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DOI
高影响因子
Journal of Spectroscopy
·
2015
·
IF 0.538
Y. J. Li,F. Y. Sun,Y. Zhou,L. Zeng
Different dispersants were added in the dispersion process to improve the efficiency of fluorite flotation. The types and dosage of dispersant on the improvement of fluorite flotation were investigated; when the sodium polyacrylate (SPA) was used as the dispersant and its addition is 0.5%, the concentrate grade of CaF2 increased from 90% to 98% and the fluorite recovery increased from 81% to 85%. Methods of X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), and Energy dispersive X-ray spectrometer (EDX) were used to characterize the sample. According to the analysis of results, the optimal sample consisted of CaF2 and very little CaCO3 in the size range of 0–5 μm. It could be concluded that the mechanism of improvement for the concentrate grade and recovery of CaF2 was attributed to the change of potential energy barrier which caused the separation of particles with different charge. All results indicate that SPA has a great potential to be an efficient and cost-effective dispersant for the improvement of fluorite flotation.
研究领域:
矿物加工工程
·
材料科学与工程
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DOI
高影响因子
JOURNAL OF NUCLEAR MATERIALS
·
2014
·
IF 2.016
Xin Wang,Kuo Jiang,Liang Zhou
Powders of (Nd 1− x Ce x ) 2 Zr 2 O 7+ y ( x = 0–1) with pyrochlore structure were prepared by sol-spray pyrolysis and subsequent graphite reduction at 1200 °C. The effects of cerium content on crystal structure, phase stability and microstructure of the (Nd 1− x Ce x ) 2 Zr 2 O 7+ y ( x = 0–1) inert matrix materials were studied. XRD and Raman results presented that all samples were in a single pyrochlore phase. XPS results indicated the cerium was in a single oxidation state of +4. After sintering at 1500 °C for 24 h in air, the sample of x = 1 underwent a phase segregation to Zr 1− x Ce x O 2 solid solutions of tetragonal, metastable tetragonal and cubic phases, the sample of x = 0.9 contained a few tetragonal phase in addition to fluorite phase, the samples of x = 0.5–0.8 had a single phase fluorite structure, the samples of x = 0–0.4 maintained the pyrochlore structure.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2025
·
IF 5
Lijia Zhu,Yimin Zhu,Wenliang Xiong,Zheng Zhou,Peng Gao,Yuexin Han
Metal ions, naturally present in flotation pulp, are commonly employed in flotation reagents, serving as vital reagents in mineral separation processes. This study investigated the impact of ASS, a blend of AlCl 3 , sulfuric acid, and sodium silicate (SS), on the flotation separation efficiency of fluorite from dolomite, as well as the underlying interaction mechanism. Micro flotation tests revealed that ASS significantly decreased the flotation recovery of dolomite while exerting negligible influence on that of fluorite. The difference in flotation recovery rates among the two minerals reached 92.00 % with the addition of 103 mg/L of ASS. The artificial mixed mineral flotation tests were also carried out, the recovery rate and grade of F in the concentrate were 86.47 % and 42.79 %, respectively. The formation of the metal complex ASS, resulting from the combination of Al with Si(OH) 4 , facilitated the adsorption of their hydrolysis products on the surface of dolomite. Within the flotation pulp system, the Ca 2+ and Mg 2+ on the dolomite surface selectively interact with the –OH groups in ASS. At the same time, the Al 3+ in ASS selectively bonds with the O atom of the carbonate group exposed on the dolomite surface. This interaction promotes the adsorption of ASS onto the dolomite surface, thereby hindering the adsorption of sodium oleate. The fluorite surface exhibited weaker interactions with ASS, leading to more sodium oleate adsorbed on the surface of fluorite, thereby increasing the hydrophobicity of the fluorite particles, which floated up. As a result, the selective adsorption of the reagents facilitated the flotation separation of fluorite from dolomite.
研究领域:
矿物加工工程
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材料化学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Yuangan Chen,Bo Feng,Huashan Yan,Liangzhu Zhang,Chunhui Zhong,Tao Wang,Huihui Wang,Longhua Xu
In this work, dextrin , an effective and eco-friendly organic compound, was used to separate fluorite from calcite . The depression performance and adsorption mechanism of it on the calcite surface were investigated by flotation experiments, contact angle measurements, Fourier transform infrared spectroscopy (FTIR) measurements, and X-ray photoelectron spectroscopy (XPS) analyses. The results showed that fluorite can be selectively separated from calcite with 10 mg/L dextrin and 2 × 10 −5 mol/L sodium laurylsulfonate (SLS). Additionally, the contact angle, FTIR and adsorption measurements indicated that the –OH group of dextrin might be adsorbed on Ca sites on the surface of calcite through chemical bonds. The inner electron binding energy of Ca 2+ in fluorite is larger than the inner electron binding energy of Ca 2+ in calcite, which makes it more difficult to form chemical bonds. Therefore, the chemical adsorption of dextrin on the surface of calcite is stronger than that on the surface of fluorite. Both SLS and dextrin can be adsorbed on the surface of calcite. However, dextrin is a strong hydrophilic compound, the hydrophilicity caused by dextrin is stronger than the hydrophobicity caused by SLS, so dextrin can selectively depress calcite.
研究领域:
矿物加工工程
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环境科学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Bo Ma,Zhiqin Wen,Jiedong Qin,Zhenyu Wu,Junxiao Liu,Yunming Lv,Junjie Yu,Yuhong Zhao
In this work, single-phase (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 2-δ high-entropy fluorite oxides (HEFOs) were successfully prepared by conventional solid-phase reaction method and crystal structure and microstructure were studied in-depth. Single-phase (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 2-δ is formed at 1600 °C for 12 h, and five cationic elements are uniformly distributed without any segregation at the micrometer and nanometer scales. And the XRD patterns with Rietveld refinement reveal the formation of single-phase fluorite structure of (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 2-δ . The SAED patterns on the [0 1 ‾ 1] band axes are similar to the diffraction patterns of face-centered cubic fluorite structure, and the standard deviation of the cation radius (coordination VIII) distribution of the specimens is 0.1277, which is again identified as forming a single-phase fluorite structure. The bulk specimens are solid compacts free of obvious cracks with randomly distribution porosity at a rare level, and the powder specimens are irregular fragmented shapes with an average particles size of 5.41 μm. The average cation radius and interplanar spacings becomes larger compared with standard fluorite structure of CeO 2 due to the cation radius of La 3+ , Sm 3+ and Nd 3+ are larger than that of Ce 4+ , leading to an increase in lattice parameters of the HEFOs. In addition, the concentration of Ce 3+ in the Ce cation is only 8.1 %, and the δ -value is calculated to be 0.3081 based on the content of all cations per mole of the substance, which indicates that the composition of the prepared specimen is (Ce 0.2 Zr 0.2 La 0.2 Sm 0.2 Nd 0.2 )O 1.6919 .
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
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
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2021
·
IF 4.539
Wenxing Zhu,Jianhua Pan,Xinyang Yu,Guichun He,Cheng Liu,Siyuan Yang,Yuhui Zeng,An Zeng,Taotao Liu
The effect of hydroxypropyl starch (HPS) on the flotation separation of fluorite from calcite using sodium oleate (NaOl) as a collector was studied. Micro-flotation results of single minerals showed that both fluorite and calcite presented good floatability in the presence of NaOl. However, by adding HPS before NaOl, the calcite flotation recovery was selectively reduced. The flotation of artificially mixed minerals confirmed that an efficient separation of fluorite from calcite could be achieved using the reagents scheme of HPS/NaOl. Zeta potential measurements demonstrated that HPS prevented the NaOl adsorption onto the calcite surface while it did not inhibit the interaction of NaOl with the fluorite surface. Fourier Transform Infrared (FT-IR) analysis was also revealed that the selective adsorption of HPS onto the calcite surface.
研究领域:
矿物加工工程
·
表面化学
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产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2019
·
IF 3.315
Cheng Liu,Shaoxian Song,Hongqiang Li
In this paper, trisodium phosphate (TSP) was utilized for the flotation separation of fluorite from barite. Micro-flotation results showed that good floatability of both fluorite and barite was obtained at around pH 8.5 using sodium oleate (NaOL) as a collector. TSP showed a selective depression for barite, and flotation separation of fluorite from barite was achieved using TSP as a depressant and NaOL as a collector. Zeta potential measurements indicated that the addition of TSP prior to NaOL did not prevent the adsorption of NaOL on fluorite surface while it prevented NaOL to adsorb on barite surface.
研究领域:
矿物加工工程
·
化学工程
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产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 105
·期 8
·5490-5500
·
IF 4.186
Liang Xu,Lei Su,Hongjie Wang,Min Niu,Lei Zhuang,Kang Peng,Xingyu Fan,Hongfei Gao,De Lu
Pursuing novel thermal barrier–coating materials with lower thermal conductivity and high-temperature stability can simultaneously improve the working efficiency and service temperature of a gas turbine. In this study, a series of high-entropy RE 2 (Y 0.2 Yb 0.2 Nb 0.2 Ta 0.2 Ce 0.2 ) 2 O 7 (RE = La, Nd, Sm, Gd, Dy, and Er) oxides were prepared though solid-state reaction. Through tuning the rare-earth cations, an order–disorder transition occurs from certain partially ordered weberite structure ( C 222 1 ) to disordered defective fluorite structure ( Fm 3 ¯ $\bar{3}$ m ). All the high-entropy RE 2 (Y 0.2 Yb 0.2 Nb 0.2 Ta 0.2 Ce 0.2 ) 2 O 7 oxides possess low thermal conductivity in the range of 0.91–1.34 W m −1 K −1 at room temperature, which can be attributed to increased lattice anharmonicity and disorder, resulting in additional phonon scattering. Herein, we proved that the incorporation of heterovalent cations at B-sites in high-entropy A 2 B 2 O 7 crystals is an effective strategy to reduce the thermal conductivity without compromising the decrease of oxygen vacancy. Moreover, the high-entropy RE 2 (Y 0.2 Yb 0.2 Nb 0.2 Ta 0.2 Ce 0.2 ) 2 O 7 oxides show the relatively higher thermal expansion coefficients of 10.3–10.7 × 10 −6 °C −1 and excellent phase stability at elevated temperatures.
研究领域:
材料科学
·
热力学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）