PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2025
·
IF 7.8
Wencheng Hou,Wentao Guo,Xiangjun Liu,Zhuoyang Li,Hongxia Li
Desulfurized gypsum, a byproduct of industrial processes, can be efficiently recycled through solid-phase reaction to synthesize CaFe 2 O 4 . This study investigates the reaction mechanism of CaFe 2 O 4 formation from CaSO 4 , Fe 2 O 3 , and semi-coke powder using thermodynamic modeling with Factsage 8.3 software. The phase composition and microstructure of the resulting products under varying semi-coke contents and sintering temperatures were characterized using X-ray diffraction (XRD) and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS). Total Fe and S contents were quantified using inductively coupled plasma optical emission spectroscopy (ICP-OES) and a C/S Analyzer. The results indicate that increasing the semi-coke content from 11.11 wt% to 20.00 wt% leads to an initial rise and subsequent decline in CaFe 2 O 4 yield, while S content exhibits an opposite trend. Similarly, elevating the sintering temperature from 1050°C to 1150°C results in increased CaFe 2 O 4 formation up to 1125°C, beyond which a decrease is observed, alongside a continuous reduction in S content. Optimal synthesis conditions were identified at 15.79 wt% semi-coke and 1125°C, achieving a desulfurization rate of 95.40 % and confirming effective formation of CaFe 2 O 4 . Compared to conventional reducing agents such as coke and C powders, the use of semi-coke enabled a reduction in the required sintering temperature from 1150°C to 1125°C. These results provide a valuable reference for the low-temperature, high-efficiency recycling of desulfurized gypsum into functional ferrite materials.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
MINERALS ENGINEERING
·
2024
·
IF 4.9
Shengzong Lan,Liuyang Dong,Peilun Shen,Haoran Su,Zhengchang Shen,Dianwen Liu
A large amount of the industrial byproduct gypsum can harm the environment, so developing an innovative approach for the utilization of gypsum is highly important. In this study, gypsum was employed to increase the flotation separation efficiency of apatite from calcite. The micro-flotation test revealed that sodium oleate could not separate the two minerals without a depressant. At pH 9, following the incorporation of gypsum, apatite achieved a recovery of 83.22 %, which was 51.49 % greater than that of calcite. The artificial mixed mineral test yielded a mixed concentrate with a P 2 O 5 recovery of 72.71 % and a grade of 25.88 %. Mineral surface properties were analyzed, revealing that gypsum enhanced the hydrophilicity of the calcite surface and inhibited NaOL adsorption on calcite but had a minimal impact on apatite. Ca 2+ in the slurry facilitated SO 4 2– adsorption on the calcite surface. X-ray photoelectron spectroscopy results indicated that phosphate species on the apatite surface could adsorb Ca 2+ from the solution, creating active sites for sodium oleate. Additionally, a higher concentration of S was observed on the calcite surface, suggesting that the adsorption capacity of gypsum dissolved in the slurry is greater on the surface of calcite. Surface morphology analysis revealed selective gypsum dissolved components adsorption on calcite rather than apatite, primarily within the 8–30 nm range, exhibiting uniform spot adsorption. These findings demonstrate the potential of gypsum as an inorganic depressant for calcite from various sources, enabling the flotation separation of apatite from calcite and thus providing a theoretical basis for the resource utilization of gypsum solid waste.
研究领域:
矿物加工工程
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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
ECOLOGICAL ENGINEERING
·
2024
·
IF 3.9
Jize Liu,Tianxue Zhang,Xiaotong Xu,Jiayi Xu,Shuang Song,Wenchao Yang,Jianbo Han
Large amounts of dredged sediment have been produced from dredging projects worldwide, and utilizing it as a resource has become particularly important. This work improved the dredged sediment using biochar (BC), humic acid (HA), and desulfurized gypsum (DG) to restore wetland substrate. The effects of different amendments, applied alone or in combination, on the physicochemical properties and nutrient contents of the dredged sediment were analyzed. The improvement effects were evaluated through reed planting experiments for three months. The results indicated that BC significantly improved the plant nutrient indicator of the dredged sediment. HA reduced the BD and pH of the dredged sediment and increased its contents of various nutrients. DG enhanced the physical indicators of the dredged sediment and could be considered for dredged sediment with high nutrient contents. The two-way ANOVA results indicated that the H3 (BC-6% + HA-6% + DG-10%) combined amendment treatment group showed the optimal improvement effect on the dredged sediment. In the reed planting experiments, the average plant height and average growth rate in the H9 (BC-6% + HA-4% + DG-20%) combined amendment treatment group were the maximum, reaching 45.18 cm and 0.486 cm/d, respectively. This work is expected to raise awareness of the need to utilize marine dredged sediments as resources.
研究领域:
环境科学
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生态学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2021
·Vol. 26
·期 4
·1154
·
IF 4.412
Minjuan Cai,Sen Quan,Jinjun Li,Feng Wu,Gilles Mailhot
Desulfurized gypsum (DG) as a soil modifier imparts it with bulk solid sulfite. The Fe(III)–sulfite process in the liquid phase has shown great potential for the rapid removal of As(III), but the performance and mechanism of this process using DG as a sulfite source in aqueous solution remains unclear. In this work, employing solid CaSO3as a source of SO32−, we have studied the effects of different conditions (e.g., pH, Fe dosage, sulfite dosage) on As(III) oxidation in the Fe(III)–CaSO3system. The results show that 72.1% of As(III) was removed from solution by centrifugal treatment for 60 min at near-neutral pH. Quenching experiments have indicated that oxidation efficiencies of As(III) are due at 67.5% to HO•, 17.5% to SO5•−and 15% to SO4•−. This finding may have promising implications in developing a new cost-effective technology for the treatment of arsenic-containing water using DG.Keywords:desulfurized gypsum;Fe(III);CaSO3;As(III);resource utilization
研究领域:
环境科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2014
·
IF 3.406
Mingyang Sun,Jiaai Hou,Guanghuan Cheng,Shams Ali Baig,Lisha Tan,Xinhua Xu
Multipurpose utilization of flue gas desulfurization (FGD) gypsums releases mercury into environment and poses threats to public health. Determining Hg speciation is essential not only for predicting its toxicity and mobility but also for designing effective remediation strategies. Sequential chemical extraction (SCE) method was used to analyze Hg speciation in this study. The total Hg concentration in four samples ranged from 0.61 to 1.63 μg/g. XRD and EDX analysis revealed that the main chemical composition of FGD gypsum was calcium sulfate (CaSO 4 ). SCE result indicated that Hg was mainly distributed in the strong complex phase, ranging from 60% to 80%. Water soluble mercury in Sample SX accounted for 30% of the total extract, which might be attributed to the relatively high chlorine content in coal. Moreover, the mobility of Hg from FGD gypsum was also investigated in this study, which exhibited biphasic kinetics. The rapid release of Hg was related to the ratio of water soluble Hg at some extent ( R 2 = 0.818), which signified of more attentions for its stabilization. This study also suggested theoretical framework for the environmental risk associated with FGD gypsum during its usage and disposal.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2024
·Vol. 39
·期 5
·1223-1228
·
IF 1.3
Cao Lijiu,Zhang Jiyao,Wang Xinqi,Zhang Xinhe,Huang Jian,Chen Yufang,Jin Tao
Through exploring the effects of low pH on the composite system of desulfurization gypsum (DG) enhanced by melamine-formaldehyde resin (MF), it is found that the inducing of sulfate-ion, in contrast to chloride and oxalate ions, favors the longitudinal growth of the crystalline form of the hydration product, which was relatively simple and had the highest length to width ( L / D ) ratio. At the same time, MF can also improve L / D ratio of gypsum hydration products, which favors the formation of hydrated whiskers. Finally, in a composite system composed of hemihydrate gypsum, MF, and glass fibers, when dilute sulfuric acid was used to regulate pH=3–4, the tight binding formed among the components of the composite system compared to pH=5–6. The hydration product of gypsum adheres tightly to glass fiber surface and produces a good cross-linking and binding effect with MF. The flexural strength, compressive strength, elastic modulus, and water absorption of the desulphurized gypsum composite board is 22.7 MPa, 39.8 MPa, 5 608 MPa, and 1.8%, respectively.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Zhiming Zhang,Lianzheng Gui,Zhuo Chen,Xingwu Li,Junda Quan,Sha Liang,Yibing Zuo,Jiakuan Yang,Yin Yang
Fly ash (FA) and flue gas desulfurization gypsum (FGD) are major solid wastes from coal-fired power plants, with high production and low utilization, leading to environmental pollution when stockpiled. Meanwhile, with the increase in energy consumption and the growing demand for building energy efficiency, there is an urgent need to develop safe and stable thermal insulation materials. In this study, an insulation composite material was developed using FGD building gypsum (FGDBG), combined with fly ash-based aerogel (FAA) with a low thermal conductivity of 0.0179 W/(m·K). At a FAA content of 25 wt%, the thermal conductivity of the FGDBG@FAA composite insulation material was as low as 0.080 W/(m·K), which is 83.71 % reduction compared to FGDBG without FAA, while the compressive strength and flexural strength reached 2.11 and 0.83 MPa, respectively. The heat transfer behavior of the FGDBG@FAA composites was further investigated by COMSOL software, and the results show that the FAA changed the heat transfer path and enhanced the overall thermal resistance of the FGDBG@FAA composites. By hydrophobically modifying the surface of the FGDBG@FAA composites, the softening coefficient increased from 0.34 to 0.85, which is sufficient to resist humid environments, while the thermal insulation and mechanical properties of the FGDBG@FAA composites kept stable. The evaluation of heavy metal leaching toxicity and radioactive nuclides indicates that the FGDBG@FAA composites are environmentally friendly. The composites developed in this study can be used for interior thermal insulation in buildings, enabling the co-disposal of FA and FGD gypsum while reducing environmental risks.
研究领域:
建筑材料
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环境科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2017
·
IF 3.169
Changzai Ren,Wenlong Wang,Guolin Li
Sulfoaluminate cement exhibits a good dimensional stability, an early strength, a high strength, a high resistance to chemical attack (from seawater, sulfates and chlorides), a low energy consumption and low carbon-dioxide emissions during production. However, sulfoaluminate cement factories traditionally use limestone, bauxite and gypsum as materials, which places significant pressure on these natural resources. This study aimed to investigate the feasibility of substituting traditional raw materials with industrial solid wastes in sulfoaluminate clinker production. It was achieved by sintering a mixture of industrial solid wastes (coal gangue: 8%–15%, flue gas desulfurization gypsum: 25%–35%, aluminum slag: 30%–35%, carbide slag: 30%–35%) at 1150–1300 °C. The mineralogical composition of the clinker was C 4 A 3 S ‾ , C 2 S and C 4 AF. The compressive strength of hydrated specimens reached as high as 75 MPa after a 28 d curing. This research provides a feasible and promising way to produce high-value products using industrial solid wastes and may promote their large-scale utilization.
研究领域:
建筑材料
·
环境科学
·
资源循环利用
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2022
·
IF 11.072
Chang Chen,Fentian Ma,Tingshu He,Zeqian Kang,Yubin Wang,Chen Shi
Flue gas desulfurization gypsum blocks were prepared using polymethylhydrosiloxane as a waterproofing and antiefflorescence agent, flue gas desulfurization gypsum as the matrix, and fly ash as the mineral admixture . The mechanical properties, water absorption, softening coefficient, surface contact angle, phase composition, and microstructure of the flue gas desulfurization gypsum blocks were determined with a universal testing machine, contact angle tester, X-ray diffractometer , Fourier-transform infrared spectrometer, and scanning electron microscopy. The salt crystallization phenomenon on the block surfaces was also observed to evaluate antiefflorescence performance. Results showed that flue gas desulfurization gypsum blocks containing 0.4 wt% polymethylhydrosiloxane had optimal overall properties. The compressive and flexural strength values were 16.03 and 6.80 MPa, respectively; the water absorption rate was 3.25%; the softening coefficient was 0.83; and the contact angle with water was 121.75°. The introduction of polymethylhydrosiloxane improved water resistance for flue gas desulfurization gypsum blocks, which also discharged water from the blocks and removed soluble salt , effectively prevented efflorescence.
研究领域:
建筑材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2022
·
IF 4.326
Shuaifeng Liu,Edouard Asselin,Zhibao Li
An industrially feasible process was proposed to produce α-calcium sulfate hemihydrate (α-HH) from FGD gypsum without any additives. In this process, an AlCl3 solution was used to promote the conversion of calcium sulfate dihydrate (DH) to hexagonal prismatic α-HH with high strength at atmospheric pressure. The phase transition kinetics of FGD gypsum was experimentally investigated under conditions: AlCl3 (2–2.5 m), MgCl2 (0–0.4 m) existing in raw FGD gypsum, and the solid–liquid ratio (or solid content %) range of 0.1–2 at 363 K. It was found that increasing the concentrations of MgCl2 in AlCl3 solution accelerated the conversion. The uniform large hexagonal prism HH product was obtained at the folowing optimal conditions: 2.5 mol/kg AlCl3, 0.4 mol/kg MgCl2, solid–liquid ratio of 2, and equilibration time of 2 h at 363 K. The phase diagram of the AlCl3-MgCl2-H2O system was determined by measuring solubility of solids. The E-NRTL activity model was used to construct the phase transition diagram of CaSO4 in AlCl3–MgCl2 media and to judge the stable range of DH and HH.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Material Cycles and Waste Management
·
2024
·
IF 2.7
Zheng Zhengqiang,Weng Changzhou,Kang Zeyu,Zhong Minhua,Yu Changyong,Lin Zhang,Liu Weizhen
In China, large amounts of industrial byproduct gypsum (IBG) end up as waste and excessive stockpiling due to its low whiteness and high impurity content. In this study, two typical IBG including phosphogypsum (PG) and flue gas desulfurization gypsum (FGDG) were the research object. The impurities removal and the whiteness improvement by the tandem pyro-hydro process were investigated. Species of impurities, mechanism of whiteness improvement and the evolution of the gypsum phase during the tandem process were revealed. The results indicate that the impurities responsible for the poor whiteness of IBG included organic matter, carbon particles, and silicates. The temperature of the pyro process is the critical factor. The IBG is calcinated at 400–500 °C to fully remove organic matter and carbon particles, while decompose silicates to silica. Following, in the hydro step, the calcined IBG was treated with dilute sulfuric acid (0.2–1.0 M) to remove ion impurities such as Fe(III), the higher temperature and higher acidity are favorable to the production of valuable CaSO 4 . After treatment, the whiteness of IBG was improved from below 40% to above 80%, and the soluble impurity content can meet the standards. Moreover, both PG and FGDG products exhibited a compressive strength exceeding 10.0 MPa of curing for 7 d. This work provides theoretical guidance to promote the resource utilization of IBG, especially as plastering materials after purification and whitening. Graphical Abstract
研究领域:
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）