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Calcium sulfate whisker prepared by flue gas desulfurization gypsum:A physical–chemical coupling production process

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Chinese Journal of Chemical Engineering 2020年第8期28卷 2221-2226页

作者： Jing Gao Qiang Li Fuli Liu College of Mining Liaoning Technical UniversityFuxin 123000China CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China College of Chemical and Environmental Engineering China University of Mining and TechnologyBeijing 100083China

In this paper,the solid waste desulfurization gypsum produced by coal-fired power plants was used as a raw material to prepare calcium sulfate whiskers with high application *** sulfate whiskers with uniform morphology and high aspect ratio can be prepared by hydrothermal method in sulfuric acid solution.A new process of desulfurization gypsum activated by high-energy grinding to reduce the reaction temperature and sulfuric acid concentration was *** the comparison of product morphology,the best grinding time was determined to be 3.5 *** mechanism of desulfurization gypsum through physical–chemical coupling to reduce energy consumption was *** activation of desulfurization gypsum by grinding and the acidic environment provided by the sulfuric acid solution made the calcium sulfate solution reached rapid saturation and accelerated the nucleation *** calculating the conversion and crystallization rate of calcium sulfate whiskers,it was found that there were obvious"autocatalytic"kinetic characteristics during the crystallization process.

关键词： flue gas desulfurization gypsum Calcium sulfate whiskers Crystallization kinetic Physical–chemical coupling

Evaluation of flue gas desulfurization gypsum as a low-cost precipitant for phosphorus removal from anaerobic digestion effluent filtrate

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International Journal of Agricultural and Biological Engineering 2024年第4期17卷 198-206页

作者： Yaping Guo Adam Khalaf Wenzhuo Kong Hongzhen Ma Jiawei Liang Dongxu Zhao Zhiguo Wang Yebo Li Fuqing Xu Technology Innovation Center for Land Engineering and Human Settlements Shaanxi Land Engineering Construction Group Co.Ltd and Xi’an Jiaotong UniversitySchool of Human Settlements and Civil EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Food Agriculturaland Biological Engineeringthe Ohio State UniversityColumbusOH 44691USA Shaanxi Environmental Survey and Assessment Center Xi’an 710054China

Land application of anaerobic digestion(AD)effluent as a fertilizer is desirable for nutrient recycling,but often supplies excess phosphorus(P),which contributes to surface water *** the P content in AD effluent filtrate using calcium(Ca)treatment prior to land application is a potential strategy for improving effluent disposal and meeting the discharge *** study took flue gas desulphurization(FGD)gypsum,a by-product of coal-fired power plants,as a low-cost Ca source,and combined with traditional phosphorus removal agents to achieve high phosphorus removal efficiency with less chemical *** the results showed,FGD gypsum dosages of 20 mmol/L Ca(3.44 g/L)and 40 mmol/L Ca(6.89 g/L)removed up to 97.1%of soluble P(initially 102.8 mg/L)within 60-90 *** FGD gypsum treatment with traditional chemical treatments using calcium hydroxide[Ca(OH)2]or ferric chloride(FeCl3)could achieve>99%P removal with reduced chemical *** study demonstrated that FGD gypsum is an efficient calcium-based precipitant for phosphorus removal,offering a cost-effective and sustainable approach to enhance wastewater treatment practices and meet discharge standards in wastewater management.

关键词： flue gas desulfurization gypsum anaerobic digestion effluent precipitation phosphorus removal eutrophication

Promotion of conversion activity of flue gas desulfurization gypsum into α-hemihydrate gypsum by calcination-hydration treatment

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Journal of Central South University 2019年第12期26卷 3213-3224页

作者： GUAN Qing-jun SUN Wei GUAN Chang-ping YU Wei-jian ZHU Xiang-nan Sultan Ahmed KHOSO WANG Ping PENG Wen-qing School of Resource Environment and Safety Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Mineral Processing and Bioengineering Central South UniversityChangsha 410083China College of Chemical and Environmental Engineering Shandong University of Science and TechnologyQingdao 266590China

The massive accumulation of flue gas desulfurization(FGD)gypsum produced in the wet limestone-gypsum flue gas desulfurization process not only encroaches on lands but also causes serious environmental *** preparation ofα-hemihydrate gypsum(α-HH)is an important way to achieve high-value utilization of FGD *** the glycerol-water solution approach can be used to produceα-HH from FGD gypsum under mild conditions,the transition is kinetically unfavorable in the mixed ***,an easy pretreatment was used to activate FGD gypsum by calcination and hydration to readily complete the *** pretreatment deteriorated the crystallinity of FGD gypsum and caused it to form small irregular flaky crystals,which dramatically increased the specific surface ***,most of the organics adsorbed onto FGD gypsum surfaces were removed after *** poor crystallinity,increased specific surface area,and elimination of organics adsorbed onto crystal surfaces effectively improved the conversion activity of FGD gypsum,thereby promoting dihydrate gypsum(DH)dissolution andα-HH ***,the phase transition of FGD gypsum toα-HH is facilitated.

关键词： flue gas desulfurization gypsum α-hemihydrate gypsum calcination-hydration treatment dissolution surface characteristics

Effect of integration of mechanical ball milling and flue gas desulfurization gypsum on dealkalization of bauxite residue

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Transactions of Nonferrous Metals Society of China 2024年第8期34卷 2702-2713页

作者： Feng ZHU Xu-yao GUO Jun JIANG Kai-bin CHEN Xuan-zhi ZHU Dan-dan DENG Yu-jun WU Yu-wei HUANG Sheng-guo XUE School of Metallurgy and Environment Central South UniversityChangsha 410083China Zhengzhou Non-ferrous Metals Research Institute Co. Ltd.of CHALCOZhengzhou 450041China College of Environment and Resources Xiangtan UniversityXiangtan 411105China School of Resources and Safety Engineering Central South UniversityChangsha 410083China

The synergistic impact of mechanical ball milling and flue gas desulfurization(FGD)gypsum on the dealkalization of bauxite residue was investigated through integrated analyses of solution chemistry,mineralogy,and *** results showed a significant decrease in Na_(2)O content(>30 wt.%)of FGD gypsum-treated bauxite residue after 30 min of mechanical ball *** ball milling resulted in differentiation of the elemental distribution,modification of the minerals in crystalline structure,and promotion in the dissolution of alkaline minerals,thus enhancing the acid neutralization capacity of bauxite residue.5 wt.%FGD gypsum combined with 30 min mechanical ball milling was optimal for the dealkalization of bauxite residue.

关键词： bauxite residue alkalinity regulation flue gas desulfurization gypsum mechanical activation soil formation of bauxite residue

Cementitious properties and hydration mechanism of Bayer red mud-carbide slag-flue gas desulfurization gypsum system

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Cementitious properties and hydration mechanism of Bayer red...

Transformation of flue-gas-desulfurization gypsum to α-Hemihydrated gypsum in Salt Solution at Atmospheric Pressure

第七届尾矿与冶金渣综合利用技术研讨会暨招远市循环经济项目招商对接会

作者： Ying Liu Wen Ni Di Huang Xuming Ma Dezhong Li Xiaoyan Huang Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants University of Science and Technology Beijing

In order to promote a better utilization of Bayer red mud as a kind of cementitious material in cemented backfill materials,and at the same time to solve the security problem of stockpiling of Bayer red mud,the hydration mechanism and cementitious properties of Bayer red mud with the active action of carbide slag and desuifurization gypsum were investigated by using the analyses of X-ray diffraction,Fourier translation infrared spectroscopy,difference scanning calorimetry-thermogravimetric,scanning microscope techniques,inductively coupled plasma optical emission spectrometry and compressive strength of the hardened *** results indicate that the hydration reaction of Bayer red mud is greatly promoted and the mechanical properties of cementitious materials are significantly improved after adding flue gas desuifurization gypsum into Bayer red mud-carbide slag *** hydration mechanism is that in Bayer red mud-carbide slag-flue gas desuifurization gypsum system,a large number of extremely low solubility ettringite is generated in hydration *** to the rapid crystallization of ettringite,the concentration of activated alumina in the system is reduced greatly,further promoting mass dissolution of soluble aluminum in Bayer red mud with ettringite continuing to be *** the other hand,as the amount of aluminum dissolution leads residual silicon to be activated in Bayer red mud which continuously generates the C-S-H gel and other hydration products,this leads to the hydration of red mud continuously.C-S-H gel and ettringite are the main strength source of this *** Cementitious material was prepared with Bayer red mud,carbide slag and flue gas desuifurization *** mechanism and cementitious properties were investigated.A large number of extremely low solubility ettringite is *** concentration of activated alumina in the system is reduced greatly due to the rapid crystallization of *** the amount of alumi

关键词： Bayer red mud carbide slag flue gas desulfurization gypsum cementitious properties ettringite hydration mechanism

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Chinese Journal of Chemical Engineering 2011年第2期19卷 349-355页

作者：吴晓琴童仕唐官宝红吴忠标 Department of Chemical Engineering Wuhan University of Science and Technology Wuhan 430081 China Department of Environmental Engineering Zhejiang University Hangzhou 310027 China

Direct phase transformation of flue gas desulfurization gypsum in hot salt solution at atmospheric pres-sure was *** effects of temperature,salt species,salt concentration,solids content,pH and modifier were *** crystals obtained under different conditions and solubility of calcium sulfate in contact with solid gypsum were also determined.α-Calcium sulfate hemihydrate crystals of stubby columnar shape and regular pentahedral sides were obtained under the following conditions：salt concentration 20%-30%,operation tempera-ture 95-100 °C,solids mass content in the slurry 10%-30% and neutral *** analysis revealed that phase transformation of calcium sulfate dihydrate to α-calcium sulfate hemihydrate occurs because of the difference in solubilities between the two solid gypsum phases in this system.

关键词： flue gas desulfurization gypsum crystal growth thermogravimetric analysis phase transformation

Influence of crystal-transforming agent on the performance and mechanism ofα-high-strength gypsum prepared from FGD gypsum

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Particuology 2024年第4期87卷 37-45页

作者： Zhuoyue Xu Xiao Wang Biao Jin Dawang Zhang Hui Li College of Materials Science and Engineering Xi'an University of Architecture and TechnologyXi'an710055China Schoolof Materials and Chemical Engineering Henan University of Urban ConstructionPingdingshan46736China

This paper investigates the impact of flue gas desulfurization(FGD)gypsum's crystal modifier on the characteristics and microcosmic mechanism ofα-high strength *** results demonstrate that all three crystal modifiers can convert FGD gypsum toα-high-strength *** acid(CA)has the most significant influence onα-high-strength gypsum,and the preparedα-high-strength gypsum is short columnar,with an aspect ratio in the range of 1-3,and has a faster setting time,a larger specific surface area,and a smaller standard consistency,higher compressive strength,greater surface hardness,and smaller crystal particle *** initial setting time of theα-high-strength gypsum manufactured with CA crystal modifier was decreased by 36%compared to the blank sample,the final setting time was lowered by 37.5%,and the water consumption of the standard consistency was reduced by 8%.The maximum strength is 32 MPa after 2 h,the absolute dry compressive strength is up to 38 MPa,and the surface hardness is improved by 24.43%.

关键词： flue gas desulfurization gypsum Crystal modifier Microscopic mechanism α-high-strength gypsum