COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2024
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IF 4.9
Yanjun Ou,Shuhua Ma,Xiaohui Wang,Hao Wu,Helong Hui,Yi Zhang
China produces over 50 % of global alumina , but its dependence on imported bauxite is as high as 65 %. Local bauxite in China is of low grade. During mining, high-grade ores were sold, while low-grade ores were left piled up on site. This practice not only occupied a large land area but also caused serious pollution. Additionally, kaolinite and diaspore are embedded in a complex and dispersed distribution on the micron scale. The physical separation and ore phase dissociation of these two (kaolinite and diaspore) are very difficult, thereby preventing the economical and efficient utilization of Chinese bauxite using existing mineral flotation and sintering technologies. Based on the analysis of the molecular structure of kaolinite , this study found a significant difference in the dissolution rates of kaolinite and diaspore in a low-alkali solution. This conclusion was drawn through a combination of kinetic analysis and experimental exploration. Therefore, a new chemical pre desilication method of diaspore bauxite rich in kaolinite was proposed. The experiment found that at temperature of 180 ℃ and Na 2 O concentration of 20 g/L, the solubility of kaolinite in a low alkali solution was 3.3 g/L. After 40 minutes of reaction, the maximum dissolution of kaolinite reached 4.2 g/L. Under the same conditions, the solubility of diaspore was 0.064 g/L. The results of kinetic study showed that the activation energy of pure kaolinite dissolution reaction was 26.77 kJ/mol, which belongs to diffusion control. Conversely, the dissolution reaction activation energy of pure diaspore was 84.30 kJ/mol, which belongs to chemical reaction control . In low alkali systems, there was a significant difference in dissolution rate between the two. By optimizing the process conditions, the optimal process conditions were found. Under the optimal conditions, the aluminum silicon ratio increased from 3.22, 2.91, and 2.68–7.92, 8.42, and 8.17, respectively, by processing three types of low-grade bauxite with different particle sizes. It is noteworthy that this method can achieve a significant increase in bauxite A/S only requiring two simple processing steps: alkali dissolution and liquid-solid separation. This study not only fills the research and application gap of low alkali solutions in the field of bauxite beneficiation, but also helps to support the green and sustainable development of the world's alumina industry.
研究领域:
矿物加工工程
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材料科学与工程
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DOI
高影响因子
Minerals
·
2020
·Vol. 10
·期 7
·594
·
IF 2.38
Pengyu Zhang,Wencai Zhang,Leming Ou,Yuteng Zhu,Zicheng Zhu
An innovative self-designed medium was packed in a bench-scale flotation column to study its influence on the flotation recovery of bauxite. Computational fluid dynamics (CFD) simulation was conducted to reveal the impact of the packing medium on the turbulent characteristics of collection zone in the column. Simulation results show that multilayer packing of the medium divides the collection zone into small units having different turbulent intensities, which is more suitable for flotation separation. The packing medium decreases the turbulence kinetic energy (from 1.08 × 10−2m2/s2to 2.1 × 10−3m2/s2), turbulence eddy dissipation (from 3.71 × 10−2m2/s3to 9.8 × 10−3m2/s3) and axial fluid velocity of fluid in the column. With three layers of packing, the recovery of Al2O3increased by 2.11% and the aluminum to silicon content ratio of the concentrate improved from 5.16 to 9.72.Keywords:flotation column;multilayer packing;bauxite;CFD
研究领域:
矿物加工工程
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化工工程
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DOI
高影响因子
Materials
·
2023
·Vol. 16
·期 9
·3506
·
IF 3.4
Cheng Chen,Chaoyi Chen,Junqi Li,Gangan Wang,Xin Lin,Deyang Ning
By utilizing low-grade bauxite desilication solution as raw material and adding lime after thermal reaction, adsorbent MCS was synthesized. X-ray diffraction, Brunauer–Emmett–Teller, Fourier transform infrared spectroscopy, and scanning electron microscopy were used to characterize the MCS, MCS-Pb, and MCS-Cu. The Freundlich model was found to be more suitable for isothermal adsorption, suggesting that the adsorption of Cu2+and Pb2+by MCS is not limited to monolayer adsorption. According to the results of the experiment, the maximum adsorption capacities of lead ion and copper ion were found to be Pb2+(1921.506 mg/g) > Cu2+(561.885 mg/g), and the adsorption was controlled by chemical reactions following pseudo-second-order kinetics. Electrolyte study results indicated that the presence of background electrolyte did not affect the adsorption of Cu2+and Pb2+by MCS.Keywords:calcium mesoporous silicate;heavy metal;low grade bauxite;adsorption
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Hang Liu,Shengqiang Song,Pin-Wen Guan,Guixuan Wu,Mithun Nath
Despite great potential in several applications, the pseudo-ternary system Al 2 O 3 –CaO–Cr 2 O x is an overlooked phase diagram due to the formation of a few toxic, carcinogenic, and water-soluble Cr 6+ compounds. In the research paper, equilibrium experimentation of selected compositions was conducted at 1073, 1373, and 1673 K and investigated using XRD , SEM-EDS, and leaching tests. Further, thermodynamic modeling of limited databases of the pseudo-ternary system Al 2 O 3 –CaO–Cr 2 O x was validated using DFT calculations. Including the recently discovered novel phase CaAl 2 Cr 2 O 7 (wuboraite), the seven phases not available in the SGTE SUBstance (SSUB) database, along with the CaCrO 4 and CaCr 2 O 4 phases existing therein, were modeled using Density Functional Theory (DFT). Based on the above experiments and the present CALPHAD model, we have calculated the isothermal sections (1073, 1373, and 1673 K) of the Al 2 O 3 –CaO–Cr 2 O x system for different oxygen partial pressures ( P (O 2 )= 0.21 atm and P (O 2 )= 10 −8 atm).
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
Microorganisms
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2025
·Vol. 13
·期 3
·612
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IF 4.2
Wenming Wang,Liling Xie,Lin Zhao,Qilin Yu
Alum mining leads to significant heavy metal and acid pollution within soils. Phytoremediation is a common strategy used to treat alum mine soils, but its efficiency is frequently compromised by the alum-mining-induced impairment of plant growth. To improve the strength of plants against mine pollution, this study constructed the artificial yeast strain ScHB (heavy metal-binding protein-containingSaccharomyces cerevisiae) expressing the de novo designed protein HBGFP (heavy metal-binding green fluorescence protein) and investigated its effect on the phytoremediation of alum mine soils with soil physiochemical assays and heavy metal quantification. This protein was composed of an N-terminal signal peptide, an HB (heavy metal-binding) domain, and a GFP (green fluorescence protein) domain, as well as a C-terminal glycolphosphatidylinositol-anchoring fragment. The exposure of the HBGFP on the ScHB surface increased the growth rate of the yeast cells and enhanced cadmium capture from the cadmium-containing medium. After culturingMedicago sativain the alum mine soils for 30 days, ScHB remarkably increased the plants’ average height from 17.5 cm to 27.9 cm and their biomass from 3.03 g/plant to 4.35 g/plant, as well as increasing the accumulation of antioxidant agents in the plants. Moreover, the ScHB cells strongly improved the soil quality, with an increase in the soil pH values from 5.47 to 6.21 to 6.9, and increased the levels of soil organic matter, total nitrogen, available phosphorus, and living bacteria. Furthermore, ScHB efficiently improved the plants’ abilities to remove soil heavy metals, decreasing the levels of cadmium, lead, chromium, and copper by 90%, 86%, 97%, and 88%, respectively. This study developed a genetic engineering method to improve the efficiency of phytoremediation against pollution from alum mining.
研究领域:
环境科学
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遗传工程
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植物学
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DOI
PubMed
高影响因子
Journal of Inorganic and Organometallic Polymers and Materials
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2022
·Vol. 32
·期 9
·3496-3507
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IF 3.518
Yang Nana,Gou Lizheng,Bai Zhitao,Cheng Fangqin,Guo Min,Zhang Mei
Zeolite Y was successfully synthesized by a hydrothermal method using bauxite tailings as starting materials to effectively remove Pb(II) from wastewater. It was shown that pure zeolite Y with typical octahedral microstructure was obtained when n(SiO 2 /Al 2 O 3 ) was 7, n(H 2 O/Na 2 O) was 35, hydrothermal at 100 °C for 10 h. The results of N 2 adsorption–desorption showed that the prepared samples possessed relatively high BET surface areas of 875 m 2 /g. The adsorption capacity of Pb(II) by the zeolite Y in aqueous solutions reached 443.87 mg/g, and the maximum removal efficiency was 99.95%. In addition, after five circulating adsorptions, the removal efficiency of Pb(II) was maintained as high as 99.2%, indicating that zeolite Y had excellent reusability. The selective adsorption results of Pb 2+ –K + –Cd 2+ ternary system solution revealed that when the concentration ratio was 1:1:1, the removal efficiency of Pb(II) was 5.5 times of Cd(II), and K(I) was almost not adsorbed. The high adsorption capacity and excellent selective adsorption of Pb(II) indicated that the zeolite Y could be a suitable absorbent for lead removal, moreover, this work explored a new way to improve the utilization of bauxite tailings.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2022
·Vol. 46
·期 7
·3409-3416
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IF 3.925
Hao Liu,Yaowei Wang,Fengqi Zhang,Congcong Xu,Xiaoyuan Liao,Yan Jiang,Shuxiang Lu
A series of K-based oxide catalysts supported on aluminium oxide (γ-Al2O3) with different surface areas were synthesized using an impregnation method and investigated by the decomposition of sulfones from oxidized diesel fuels. The synthesized catalysts were characterized by N2 adsorption–desorption isotherms, CO2-TPD and HR-SEM methods to explore the relationship between the structure of the catalysts and sulfone conversion. The results showed that the K element was highly dispersed on the surface of γ-Al2O3. The prepared catalyst was further applied in the decomposition reaction of dibenzothiophene sulfone (DBTS) to evaluate the catalytic performance. The sulfone conversion could achieve 63.9% in 10% K2O/3-Al2O3 within 20-minute reaction time at 260 °C. Moreover, our experimental test showed that the sulfone conversion was linearly correlated with the logarithm of the total basic sites of the K2O/γ-Al2O3 catalyst.
研究领域:
化学工程
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催化科学
✓ 已验证
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
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2021
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IF 5.039
Yuxiao Xue,Jian Pan,Deqing Zhu,Zhengqi Guo,Hongyu Tian,Yue Shi,Shenghu Lu
Iron ores always contain several forms of alumina, which may have different effect on sintering performance. In this paper, sinter pot tests were systematically conducted with various alumina types and contents by means of alumina additives substituting for the corresponding types of alumina, and the relevant action mechanism on sintering performance was clarified by the mineralogy of product sinter. The results show that kaolinite is beneficial to the granulation process rather than other three alumina types. In addition, it contributes to relatively better sintering performance while aluminous goethite ranks the only next, followed by gibbsite and free alumina. Mechanism analysis indicates that kaolinite and aluminous goethite are preferable to achieve relatively lower sinter porosity and higher amount of silico-ferrite of calcium and alumina (SFCA) compared with gibbsite and free alumina. Besides, the former two alumina types are apt to promote the formation of higher strength SFCA such as dendritic and acicular SFCA. Furthermore, much tighter interlocking texture in product sinter is formed as alumina occurs in kaolinite or aluminous goethite. Kaolinite and aluminous goethite are the preferably desirable alumina types for sintering rather than free alumina and gibbsite.
研究领域:
冶金工程
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材料科学
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DOI
高影响因子
HYDROMETALLURGY
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2025
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IF 5.3
Muhammad Ibrahim,Yanjun Ou,Shuhua Ma,Xiaohui Wang
Ferric and titanium oxides are the main impurities in low-grade bauxite that significantly affect alumina extraction in the Bayer process. This study aims to investigate the reaction and transformation behavior of ferric and titanium oxides in diasporic bauxite during a mild alkaline hydrothermal process to minimize the inhibitory effects of Fe and Ti impurities on bauxite digestion. Analytical techniques such as X-ray diffraction, X-ray fluorescence, inductively coupled plasma, scanning electron microscopy with energy dispersive X-ray spectroscopy, mineral liberation analysis, and Mössbauer spectroscopy were used to analyze the occurrence states of impurities in the raw bauxite and residue, explain their reaction mechanisms, and understand their transformation under hydrothermal conditions. Starch was used as a reducing agent to transform hematite into magnetite and facilitate the subsequent reaction of magnetite with anatase to minimize adverse effects. Thermodynamic calculations and results from experimental investigations showed that under optimized operating conditions of 180 °C, reaction time of 90 min, alkali concentration of 60 g/L, and a small quantity of starch, significant transformations of iron and titanium occurred. These include transformation of (i) hematite to magnetite (54.8 %) and (ii) anatase to Ti-containing stable phases such as ilmenite (19.7 %), ferrous pseudo brookite (12.7 %), ulvite (12.9 %) iron titanate, and perovskites. After the pretreatment with bauxite, alumina digestion can exceed 90.0 %.
研究领域:
矿物加工工程
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材料科学与工程
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产品关联
DOI
高影响因子
PLANT AND SOIL
·
2023
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IF 4.9
Xue Shengguo,Zhang Yufei,Jiang Jun,Li Feng,Chen Chaorong,Guo Xuyao,Chen Qi,Zhu Feng,Chen Hualin,Wu Yujun
Purpose The interaction of minerals and organic matter significantly affects the stability of organic carbon, which is key to the rehabilitation of bauxite residue. However, due to the microscopic structure of minerals and the chemical composition of dissolved organic matter (DOM), the interaction mechanism between alkaline minerals and DOM in the presence of calcium ions that are widely used as amendments is still poorly understood. Methods In this work, the mechanism of adsorption and immobilization of organic matter by sodalite and cancrinite in the presence of calcium ions was investigated at the microscopic scale, using Fourier transform infrared spectroscopy (FTIR), excitation-emission matrix fluorescence (EEM) spectra, thermogravimetric analysis (TG) and atomic force microscope (AFM). Results The calcium ions can act as bridges to connect the negative sites on the mineral surface with the polysaccharide functional groups of organic matter, thus promoting organic carbon sequestration via ligand exchange and/or electrostatic interactions. Furthermore, DOM located in the structure within the cancrinite surface may be better protected due to physical isolation. The 3D view of the interacted minerals-organic matter assemblages provided visual evidence that the adsorption sites distributed on the surface of cancrinite increased by the action of calcium ions, with different adsorption capacities of individual sites for DOM. Conclusions The calcium ions enhance the ability of alkaline minerals to trap dissolved organic carbon, and the work highlighted the significance of organo-mineral associations in the microscopic mineral structure for the organic carbon sequestration in the revegetation process of bauxite residue disposal areas.
研究领域:
环境科学
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土壤学
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DOI
高影响因子
FUEL
·
2021
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IF 6.609
Haifeng Li,Tao Liu,Sheng Su,Mei Jin,Wen Fang,Lijun Liu,Yi Wang,Song Hu,Jun Xiang
Ce modified Mn x O y /Al 2 O 3 -La have been prepared to investigate the effect of Ce loadings on pre-breakthrough H 2 S removal efficiency, breakthrough sulfur capacity (BSC) and BSC durability of the sorbents during desulfurization-regeneration cycles. The results showed Ce modification could improve the pre-breakthrough H 2 S removal efficiency of regenerated sorbents during desulfurization-regeneration cycles. The XPS characterization showed that the Ce can promote the binding energy of Mn ion to shift to lower energy, which enhanced H 2 S adsorption on the regenerated sorbent. However, the Ce loading sequence had effect on BSC durability of sorbent during desulfurization-regeneration cycles. The Ce-Mn x O y /Al 2 O 3 -La with co-impregnation of Mn and Ce oxides had higher BSC than Mn x O y /Al 2 O 3 -La, while the Ce/Mn x O y /Al 2 O 3 -La with Ce loading on the surface of Mn x O y /Al 2 O 3 -La had lower BSC and worse BSC durability than Mn x O y /Al 2 O 3 -La. The characterization results showed Ce-Mn x O y /Al 2 O 3 -La obtained better surface area and pore structure than Mn x O y /Al 2 O 3 -La, and Ce ion can promote the increasing of the around electron density of Mn ion, which was beneficial for H 2 S adsorption of Ce-Mn x O y /Al 2 O 3 -La. The poor surface area and pore structure would cause the low BSC of Ce/Mn x O y /Al 2 O 3 -La, and less stability of pore structure might lead to poorer BSC durability of Ce/Mn x O y /Al 2 O 3 -La than Mn x O y /Al 2 O 3 -La during desulfurization-regeneration cycles.
研究领域:
化学工程
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材料科学
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产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2015
·Vol. 17
·期 16
·3110-3116
·
IF 4.034
Qiuru Wang,Yanyan Wang,Yafei Zhao,Bing Zhang,Yunyin,Niu,Xu Xiang,Rongfeng Chen
Technological applications of heterogeneous nanocatalysts on supports have generally relied on the surface or interface properties of supports. Herein, we report a facile approach to fabricate roughened surfaces on halloysite nanotubes (HNTs) through etching the wall of HNTs in a molten-salt system. SEM, TEM, XRD, FTIR, AFM and N2 adsorption/desorption analysis are employed to systematically investigate the morphology, structure and surface properties. The results suggest that the roughness of HNTs surface has been significantly increased and defects are formed on the tube wall without structural damage. Subsequently, the roughened halloysite nanotubes (RHNTs) are used as supports to prepare heterogeneous nanocatalyst. Pt nanoparticles with a uniform size can be homogeneously deposited onto the RHNTs surfaces via a one-step hydrothermal reduction. The as-prepared Pt@RHNTs catalyst exhibits remarkably improved activity and selectivity for the hydrogenation of cinnamaldehyde towards cinnamyl alcohol compared with the pristine halloysite support. Furthermore, Pt@RHNTs catalyst shows rapid catalytic rates in hydrogenation reactions and excellent leaching resistance in cycle uses.
研究领域:
材料科学
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催化化学
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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）