Minerals
·
2021
·Vol. 11
·期 6
·555
·
IF 2.644
Chenhu Zhang,Jiande Gao,Yuehua Hu,Wei Sun,Fei Lv,Zhenjun Liu
Fluorite is a nonrenewable mineral used to produce anhydrous hydrofluoric acid (AHF) and aluminum fluoride. The demand for low-grade fluorite powder (CaF2< 97%) has fallen sharply owing to the current market conditions. Therefore, a large number of fluorite concentrates have been improved by acid leaching. While this approach can efficiently remove CaCO3from fluorite concentrate, the SiO2content, which significantly affects AHF consumption during the production of HF or aluminum fluoride, cannot be completely removed. To solve this problem, in this study, we used reverse flotation before leaching the fluorite concentrates. Subsequently, the feasibility of reverse flotation desilication was determined. The obtained results of the ZP (zeta potential) measurements, solution chemistry analysis, FTIR (Fourier transform infrared spectroscopy) analysis, and micro-flotation tests indicated that employing dodecylamine as the collector and citric acid as the depressor could effectively separate sericite from fluorite. The batch flotation experiment and the pilot test were conducted in Chenzhou (Hunan, China) followed by their operation in Xinyuan Mining Co. Ltd., which produces monolithic fluorite ore on the large scale in Asia. Notably, we found that the contents of both SiO2and Al2O3were from 2.82%, 1.17% reduced to 1.28%, 0.74% in the batch flotation experiment. The results of the pilot test showed that the new reverse flotation + leaching technology could dramatically reduce the potential environmental impact and costs, thereby significantly improving the economic benefits by satisfying the requirements of the market.Keywords:fluorite;desilication;reverse flotation;leaching
研究领域:
矿物加工工程
·
环境科学与工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Yun Guo,Hong-Yi Li,Jie Cheng,Shuo Shen,Jiang Diao,Bing Xie
The V-Cr-bearing reducing slag (VCBRS) is solid waste, which cannot be treated at present. This work proposes an effective approach to separately recover its major elements of V, Cr and Si and fully utilize the VCBRS with added-values. Flocculation desiliconization is used to extract Si from the acid solving liquid of VCBRS and Si is recovered as white carbon black with purity of 94.60% and recovery of 93.04%. After desiliconization, V in the solving liquid is selectively oxidized by H 2 O 2 and extracted by microemulsion extraction, which is recovered as V 2 O 5 whose purity is 99.60% with recovery at 96.32% from the stripping liquor of loaded microemulsion . Cr in the raffinate is recovered by alkaline precipitation as final product of Cr 2 O 3 with purity of 98.83% and recovery of 92.68%. The principles are discussed in detail and the operation conditions are optimized systematically. The microemulsion and wastewater are both cyclically utilized, which eliminates the secondary wastes. This work efficiently recovers all valuable elements with increased values from the solid waste, which can not only solve the environmental pollution problem, but also realize the efficient recovery of valuable elements to achieve comprehensive utilization.
研究领域:
冶金工程
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2024
·
IF 5.3
Zhonghua Xue,Yali Feng,Haoran Li
Investigating the reverse flotation desilication process of magnesite tailings (MT) holds substantial merit in the context of magnesium metal recovery from solid waste. However, scant attention has been devoted to exploring the influence of the carbon chain length of diverse alkanes on the reverse flocfloatation desilication of MT. This research systematically delved into the selective adsorption behavior exhibited by dodecylamine (DDA) and its compound collectors on the surfaces of quartz and magnesite. As the carbon chain length of alkanes increases, the efficacy of reverse flotation desilication of MT diminishes. Under optimized conditions, the concentration of MgO in the concentrate registers a 0.93% increment, accompanied by a 2.05% reduction in SiO 2 content. The optimal MgO grade attains 42.68%. The augmenting carbon chain length of alkanes leads to a decline in the dispersibility of the compound collector and a reduction in the diffusion coefficient of the monolayer film at the alkane/water interface. The compound collector, comprising n-heptane and DDA, manifests a noteworthy synergistic promotion effect on the flotation desilication of MT. This effect reduces the multilayer adsorption of DDA, promotes more hydrogen bonding formation, and favors DDA adsorption on the quartz surface over magnesite. Consequently, issues related to froth entrapment and poor selectivity are alleviated. Longer alkane chains in the compound collectors result in a stronger van der Waals force effect between the carbon chains. This effect causes DDDA to slide more easily on the quartz surface, which is not conducive to enhancing the hydrophobicity of the surface. Furthermore, alkane-induced hydrophobic flocculation increases the floccules size of quartz, enhancing the likelihood of bubble-particle adhesion. This investigation elucidates the molecular-level mechanism underlying alkane hydrophobic flocculation with varying chain lengths, contributing a theoretical foundation and technical support for the large-scale MT management and the sustainable production of magnesium metal.
研究领域:
矿物加工工程
·
材料科学与工程
✓ 已验证
产品关联
DOI
高影响因子
PLoS One
·
2025
·Vol. 20
·期 2
·e0316172
·
IF 2.6
Nian Liu,Chaoyi Chen,Junqi Li,Dong Liang
The raw material for smelting brown corundum is high-quality bauxite. As the quality of bauxite decreases, the main impurity, silicon content, increases, which affects the product quality and smelting energy consumption. Additionally, the smelting process produces a significant amount of brown corundum fly dust (BCFD) with a low utilization rate, resulting in resource wastage. In order to utilize low-quality bauxite and BCFD, this article proposes the method of “roasting-alkali leaching.” Through mixed desilication, the impact of alkali leaching factors on desilication is investigated, analyzed the desiliconization mechanism of BCFD, and established the kinetics of the desilication reaction. Results indicated that the optimal conditions for mixed desilication are BCFD/bauxite mass ratio of 1:6, desilication temperature of 95°C, desilication time of 30 min, alkali concentration of 110 g/L, and liquid-solid ratio of 10:1, achieving a desilication rate of 60.90%. The Al-Si ratio (A/S) of the concentrate increases from 5.33 to 11.72, meeting the requirements for brown corundum smelting raw materials. The desilication reaction follows a solid shrinkage core model, with a kinetic equation of 1−2/3α−(1−α) 2/3 = 15.50exp[−29299/(RT)]·t, and an apparent activation energy of 29.30 kJ/mol. The synergistic mechanism involves fine particles of the BCFD adsorbing on the surface after mixing with the bauxite, increasing the mineral surface area and the activity of silicon, thereby accelerating the reaction rate.
研究领域:
冶金工程
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
·
IF 3.573
Hang Li,Yi Zhai,Xubin Zhang,Guojun Lv,Yu Shen,Xuqing Wang,Tao Jiang,Yuzhou Wu
Hierarchical iron-containing TS-1 zeolites (FTS) were successfully synthesized via post-treatment desilication over microporous Fe-TS-1, which were prepared through a one-step hydrothermal synthesis. The prepared samples were characterized by X-ray diffraction, N2 adsorption–desorption, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, ultraviolet visible spectroscopy, and X-ray fluorescence spectrometry. The experimental results illustrated that the MFI structure of all the FTS samples remained unchanged after NaOH desilication and acid treatment. The newly created mesopores can be controlled by changing the amount of framework Fe, as the extraction of Si could be affected because of the inhibitory effect of iron species during the desilication process. The catalytic performance of the prepared samples in phenol hydroxylation with H2O2 was investigated. Among all the samples, FTS-50-D showed a highest phenol conversion of 45.2% and a dihydroxybenzene selectivity of 95.2%. Besides, FTS-50-D also showed good reusability for five recycling tests.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2019
·
IF 4.182
Aihu Feng,Yang Yu,Le Mi,Yunzhen Cao,Yun Yu,Lixin Song
The non-framework aluminum is inevitably formed in the process of preparing the ultra-stable Y zeolite (USY), which severely blocks the mesopores of USY zeolite. It is necessary to treat the USY with the appropriate acid and/or alkali. In this paper, the USY zeolite is firstly dealuminated with NH 4 HF 2 solution and then desiliconized with NaOH or NH 4 OH solution. The effect and mechanism of NH 4 HF 2 and different alkali treatments on the structural and textural property of USY zeolite are elaborately demonstrated. It is found that the non-framework Al remaining in the mesopores of USY is significantly removed by the NH 4 HF 2 solution. The desiliconization reaction is more likely to start near the mesoporous wall because the Al concentration in here is low and the repulsive force against OH − is weak. The OH − ions from NaOH solution not only etch the framework Si near the inner wall of the mesopores, but also remove the Si on the surface of NH 4 HF 2 -etched USY zeolite. However, the concentration of OH − ions is too low when NH 4 OH is used as the desiliconization agent, the OH − ions just react with silicon around the mesopores. Therefore, the NaOH/NH 4 HF 2 -etched USY contains both some micropores and macropores, and the NH 4 OH/NH 4 HF 2 -etched USY only possesses more mesopores with pore sizes of ～10 nm. In addition, NaOH/NH 4 HF 2 -etched USY exhibits excellent toluene adsorption performance at low pressure stage, while NH 4 OH/NH 4 HF 2 -etched USY has the highest adsorption capacity on toluene at high pressure stage.
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
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Jingxiang Sun,Wen Yan,Xiaosheng Liu,Tao Hu,Ya Xiong,Shuanghong Tian,Jinxi Feng,Zhen Huang,Zengli Zhao
A super-carbon material as adsorbents of CO 2 were prepared with rice husk waste by a new two-step process, pyrolysis-activation and HF post-desilication process. This paper was focused on investigating the boosting effect and mechanism of post-desilication. It was found that the function of the post-desilication was considerably different from that of the reported pre-desilication. It could not only effectively remove Si element from rice husk biochar (RHC) but also significantly improve its performance, producing a super-biocarbon with a well-developed pore structure, rich C-F groups, and a 4230-m 2 g −1 surface area, which is the max surface area of known biocarbon. It could adsorb 341.5 mg g − 1 CO 2 , a max CO 2 adsorption capacity of reported biocarbon, and its CO 2 /N 2 and CO 2 /H 2 O adsorption selectivity index reached as high as 22.2 and 2.1, respectively. The large surface area was mainly originated from the expansion effect of SiF 4 gas from the post-desilication, generating numerous ultra-microspores, while these C-F groups were generated by the co-reactions of the post-desilication. The ultra-high adsorption capacity was mainly from the fill-adsorption driven by the size effect of these ultra-micropores and the strong CO 2 -affinity of C-F groups, and the adsorption selectivity was confirmed to depend on water-resistant and CO 2 -philic characteristics of its C-F groups by theoretical calculations and experimental observations. These findings presented not only an advanced CO 2 -capture material but also a facile way to tailor textural structure of other biochars.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Separations
·
2024
·Vol. 11
·期 2
·39
·
IF 2.5
Zhenhua Sun,Qingxiang Shu,Qikun Zhang,Shaopeng Li,Ganyu Zhu,Chenye Wang,Jianbo Zhang,Huiquan Li,Zhaohui Huang
ZSM-5 zeolite is a kind of high-value-added porous aluminosilicate zeolite. The use of the coal gasification slag utilization process by-product desilication liquid as a silicon raw material to replace the current raw materials such as water glass will help reduce production costs and achieve high-value utilization of solid waste. ZSM-5 zeolites for volatile organic compounds (VOCs) adsorption were prepared by a one-step hydrothermal method using the desilication solution prepared from coal gasification slag as the main silicon source and sodium source. The effects of crystallization reaction time, the crystallization temperature, the Na2O/SiO2molar ratio, and the SiO2/Al2O3molar ratio on the relative crystallinity and the specific surface area of the ZSM-5 zeolite were investigated and optimized. The optical reaction conditions were as follows: a crystallization time of 12 h, a crystallization temperature of 170 °C, a Na2O/SiO2molar ratio of 0.2, and a SiO2/Al2O3molar ratio of 200. The optimal ZSM-5 zeolite synthesized is hexagonal, with regular grains, a relative crystallinity of 101.48%, a specific surface area of 337.48 m2·g−1, and a pore volume of 0.190 cm3·g−1. And the optimal ZSM-5 zeolite was composed of SiO2content of 97.52 wt%, Al2O3content of 1.58 wt%, Na2O content of 0.33 wt%, and SiO2/Al2O3molar ratio of 104.93. Na2O/SiO2molar ratio is 0.0033. The results of static adsorption experiments show that the static adsorption capacities of ZSM-5 zeolite forp-xylene, benzene, toluene, and butyl acetate were 118.85, 69.98, 68.74, and 95.85 mg·g−1, respectively, which can effectively adsorb VOCs. The synthetic process of the ZSM-5 zeolite is a simple preparation process and short in synthesis time. The results of this study not only help to realize the high-value utilization of silicon components in solid waste, but also provide an economical and effective way to synthesize VOCs adsorption materials.
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
SCIENCE OF THE TOTAL ENVIRONMENT
·
2023
·
IF 9.8
Tongyao Ju,Yuan Meng,Siyu Han,Fanzhi Meng,Li Lin,Jinglin Li,Jianguo Jiang
Coal fly ash (CFA) is a typical industrial solid waste, which has recently been reported to contain rare earth elements (REEs). REEs are important materials in many industrial fields. Therefore, extracting REEs from CFA becomes a win-win strategy to both make full use of CFA and reclaim REEs. However, the stable crystalline structure of CFA is hard to break, which limits the extraction of REEs. The inter-correlation and the leaching patterns of the REEs in CFA also remain unclear. In this work, REEs were enriched by desilication, and the correlation and the influences of multiple acids of the leached REEs were investigated. It was found that desilication could increase the leachable amount of REEs from 137.37 ppm to 346.12 ppm. The light rare earth elements (LREEs) were less inter-correlated than heavy rare earth elements (HREEs) and desilication enhanced the leaching of LREEs more than that of HREEs. The ratio and type of the leaching acids both influenced the extraction of REEs from CFA: HCl and HF played important roles in the extraction from the untreated CFA while HNO 3 and HF were more decisive for the desilicated CFA. In addition, we used statistical analysis to quantificationally confirm that desilication and acids both significantly influenced the extraction of REEs. This work provides evidence for the enrichment of REEs in CFA and acid choosing when leaching REEs from CFA.
研究领域:
环境科学
·
材料科学
·
化学
·
废物管理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yi-Hong Wu,Wei Guo,Yu-Zhu Sun,Shu-Ying Sun
Coal-based solid waste, as a secondary resource, contains significant quantities of aluminum, silicon, and lithium resources. The desilication solution is a waste solution with low concentrations of lithium ions, which is produced during the resource utilization process of coal-based solid waste. Developing adsorbents with high lithium selectivity and alkaline stability is important for the recovery of lithium in coal-solid waste alkaline leachate. In this study, resin functionalized with 2-hydroxymethyl-12-crown-4 (2H12C4) is prepared by esterification. The reaction conditions, including resin type, reaction temperature, time, and catalyst dosage, are optimized. The selective adsorption of 2H12C4-D113 is evaluated in a simulated desilication solution. The results show that 2H12C4-D113 with high selectivity for Li + adsorption is successfully synthesized at 1 g of 2H12C4 per g of resin, 110 ℃ reaction temperature, 6 h reaction time, 0.5 g of catalyst per g of resin and 1 mol of anhydrous lithium chloride per mol of 2H12C4. The adsorption rate of the 2H12C4-D113 resin is relatively rapid, and its adsorption kinetics satisfy the proposed second-order kinetic curve, and its Li + adsorption capacity is greatly influenced by Li + concentration. The peaking adsorption capacity of this resin is 58.71 mg/g in pure lithium solution (Li + =200 mg/L) with high alkalinity, and the peaking adsorptive capacity is 9 mg/g in the pre-desilication solution (Li + =274 mg/L, Na + =101 g/L). Furthermore, density functional theory (DFT) is utilized to study the selective adsorption mechanisms, geometrical characteristics, and thermodynamic parameters of the complexes between crown ether and different ions. DFT simulation reveals that 2H12C4-D113 has high selectivity for Li + adsorption with a Li + -O bond length of 1.86–1.88 Å, and an adsorption energy of 2H12C4-Li + (−369 KJ/mol) being the highest among the mental ions.
研究领域:
材料科学
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环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2012
·
IF 2.159
Yuxin Wang,Kaituo Liu,Tao He,Jinhu Wu,Yunming Fang
Zeolite with trimodal porosity can be synthesized by desilication of zeolite nanocrystal aggregate. In the desilication process, the originally existed intercrystalline mesopores of zeolite nanocrystal aggregate were enlarged into large mesopore, and the new small intracrystalline mesopore channel was created, thus the Zeolite with trimodal porosity was formed. The structure of resulted zeolite, both on aggregate and mesopore level can be fine tuned by the desilication degree.
研究领域:
材料科学
·
多孔材料
·
纳米材料
·
催化化学
·
无机合成
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2025
·
IF 2.5
Guohao Xu,Jiaqi Liu,Xin Gao,Xuedong Zhu
Hollow b-oriented ZSM-5 with a thickness of approximately 80 nm was synthesized for methane co-aromatization with propane (MCP) through the desilication–recrystallization of b-oriented ZSM-5 using tetrapropylammonium hydroxide (TPAOH) as a template. A hollow structure was introduced into b-oriented ZSM-5 via desilication with OH− and a thin intact shell was formed during recrystallization of leached Si species under TPA+ template application. By regulating the recrystallization time, shell thicknesses could be controlled from 120 nm to 60 nm. Under a recrystallization time of 24 h, the hollow b-oriented ZSM-5 possessed suitable acidity as well as the largest SBET and daver. When the hollow b-oriented ZSM-5 zeolite was used as the support for a zinc-based catalyst, aromatic selectivity and the conversion of methane and propane were improved. A maximum aromatic selectivity of 87.5% was achieved, with methane and propane conversion of 10.7% and 77.9%, respectively.
研究领域:
催化化学
·
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）