Study on Flue Gas Desulphurization Gypsum Plaster

2011 ◽  
Vol 71-78 ◽  
pp. 842-846
Author(s):  
Miao Miao Chen ◽  
Yun Wei Yu ◽  
Chun Hua Feng ◽  
Dong Xu Li
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Water Retention ◽  
Setting Time ◽  
Strength Loss ◽  
Optimum Level ◽  
Fgd Gypsum ◽  
Gypsum Plaster ◽  
Calcined Gypsum ◽  
Flue Gas Desulphurization

Flue gas desulphurization (FGD) gypsum and fly ash are two kinds of solid waste in coal-fired power plant. The possible displacement content of fly ash in gypsum plaster was investigated in this paper. The effect of various chemicals retarders, such as Citric acid, sodium citrate and SC gypsum retarder, and water retention agent on the setting time, flexural strength and compressive strength of gypsum plaster was also studied. The results demonstrate that gypsum plaster has maximum mechanical properties and enough setting time at the rate of 20% fly ash replacing calcined gypsum; SC gypsum retarder effectively delays the setting time and has lower strength loss; The optimum level of water-retention agent for effective utilization of gypsum plaster is 0.2%.

On Experimental Study of Development Calcined Gypsum from Flue Gas Desulfurization by Microwave Technology

2013 ◽  
Vol 368-370 ◽  
pp. 780-784 ◽  
Author(s):  
Zhi Man Zhao ◽  
Chun Jie Wang ◽  
Can Qion Li ◽  
Xiao Mei Zhang
Keyword(s):  
Microwave Irradiation ◽  
Flue Gas ◽  
Calcium Sulfate ◽  
Setting Time ◽  
Flue Gas Desulfurization ◽  
Crystal Formation ◽  
Special Effect ◽  
Fgd Gypsum ◽  
Calcined Gypsum ◽  
Cylindrical Crystal

Flue gas desulfurization gypsum (FGD gypsum) was irradiated with microwave, it could be changed calcined gypsum from flue gas desulfurization (CGD). The microwave respectively irradiated five groups FGD gypsum at 100-110°C, 110-120°C, 120-130°C, 130-140°C and 140-150°C, then the fineness and setting time were respectively measured, and compressive/flexural strength were also determined after 2 hours. Experiments show that, CaSO4·0.5H2O crystal of CGD would be more quantity and bigger volume with irradiation temperature increasing. The reason was considered that there were special effect of microwave irradiation to calcium sulfate crystalsthat by scanning electron microscope, and found the Ca, S, O and other elements in cylindrical crystal by Edax. The formation mechanism of CaSO4·0.5H2O crystal by microwave irradiation is different from traditional CaSO4·0.5H2O crystal formation theories.

Heat Treatment Process of the Flue Gas Desulphurization Gypsum and its Influence on the Properties of Cement

2012 ◽  
Vol 214 ◽  
pp. 40-44
Author(s):  
Yue Li ◽  
Jian Hui Wu ◽  
Bin Hao ◽  
Da Cheng Liu
Keyword(s):  
Heat Treatment ◽  
Flue Gas ◽  
Setting Time ◽  
Treatment Temperature ◽  
Strength Development ◽  
X Ray Diffraction ◽  
Fgd Gypsum ◽  
Treatment Processes ◽  
Cement Setting ◽  
Flue Gas Desulphurization

The Crystal Transformation of flue gas desulphurization (FGD) gypsum was analyzed by differential thermal analysis (DTA) and X-ray Diffraction (XRD). FGD gypsum was used as cement setting retarder and the influences on the properties of cement were studied by treating FGD gypsum at different heat treatment processes. The results reveal that in the case of adding the same amount, the setting time of cement shortened with the increasing of heat treatment temperature of FGD gypsum. The influence of different heat treatment processes on the strength of cements was not obvious and the strength development was good. The water consumption of normal consistency for cements changed slightly. Stability was qualified.

scholarly journals Orthogonal Experimental Studies on Preparation of Mine-Filling Materials from Carbide Slag, Granulated Blast-Furnace Slag, Fly Ash, and Flue-Gas Desulphurisation Gypsum

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Mingyue Wu ◽  
Xiangming Hu ◽  
Qian Zhang ◽  
Weimin Cheng ◽  
Zunxiang Hu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Flue Gas ◽  
Blast Furnace Slag ◽  
Raw Materials ◽  
Setting Time ◽  
Fgd Gypsum ◽  
Granulated Blast Furnace Slag ◽  
Carbide Slag ◽  
Furnace Slag

Environmentally friendly and cheap composite green cementitious materials have been prepared from carbide slag, fly ash, flue-gas desulphurisation (FGD) gypsum, and granulated blast-furnace slag (GBFS) without using cement clinker. Orthogonal testing was used to investigate the effects of the raw materials on the amount of water required for reaching standard consistency and consistency, setting time, slump value, and strength of the produced materials after curing for 7 d and 28 d. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques were used for the analysis of the sample microstructure and hydration products as well as for the exploration of possible hydration mechanisms. We found that, among the utilised raw materials, the addition of FGD gypsum had the most significant effect on the setting time and amount of water required for reaching standard consistency and consistency, while the addition of GBFS deeply affected the slump value. The optimal activation results were obtained when the mass ratio of carbide slag : fly ash : GBFS : FGD gypsum was equal to 12.1 : 60.6 : 18.2 : 9.1.

The Properties of Flue Gas Desulphurization (FGD) Gypsum

2011 ◽  
Vol 105-107 ◽  
pp. 2204-2208 ◽  
Author(s):  
Run Xia Hao ◽  
Xiao Yan Guo
Keyword(s):  
Mechanical Properties ◽  
Flue Gas ◽  
Steel Slag ◽  
Optical Microscope ◽  
Cementitious Material ◽  
Fgd Gypsum ◽  
Technical Performance ◽  
Slag Powder ◽  
Steel Slag Powder ◽  
Flue Gas Desulphurization

The properties of flue gas desulphurization (FGD) gypsum were analysized by Thermo-gravimetry/differential scanning calorimetry (TG/DSC), technical performance analysis, optical microscope and Scanning electron microscope (SEM). Mechanical properties of FGD gypsum-steel slag powder cementitious material were researched. The results revealed that FGD gypsum have similar moisture content, major component CaSO4·2H2O with natural gypsum, and has better technical performance than natural gypsum. The results of optical microscope and SEM of the FGD gypsum hydration support this further. When the dosage of steel slag powder is 15%, containing activator ,better mechanical properties can be obtained. Key words: FGD gypsum, Property, Cementitious material

Effect of Kaolin on the Properties of Flue Gas Desulphurization Gypsum-Steel Slag Cementitious Materials

2011 ◽  
Vol 306-307 ◽  
pp. 1553-1556
Author(s):  
Lei Zhang ◽  
Zhi Wang ◽  
Li Ying Fan ◽  
Guo Pu Shi
Keyword(s):  
Flue Gas ◽  
Setting Time ◽  
Steel Slag ◽  
Cementitious Materials ◽  
Cementitious Composites ◽  
Excitation Mechanism ◽  
Final Setting Time ◽  
Micro Morphology ◽  
Scanning Electron ◽  
Flue Gas Desulphurization

The effects of kaolin on the properties of flue gas desulphurization gypsum-based steel slag composites were analyzed in this article and the influence rules of setting time, final setting time on the flexural strength and compressive strength of cementitious composites were also discussed. The micro-morphology of the composite was observed by scanning electron microscope. At the same time, the excitation mechanism of kaolin on gas desulphurization gypsum-based steel slag was put forward. It was demonstrated that kaolin with content of 3% in the composites can better stimulate the activity of steel slag and improve the mechanical properties of cementitious composites.

Preparation of FGD Gypsum-Fly Ash Plaster Material

2013 ◽  
Vol 327 ◽  
pp. 28-31
Author(s):  
Jiang Zhu ◽  
Guo Zhong Li ◽  
Chuan Wei Du
Keyword(s):  
Fly Ash ◽  
Citric Acid ◽  
Material Properties ◽  
Reducing Agent ◽  
Mass Ratio ◽  
Sodium Metaphosphate ◽  
Fgd Gypsum ◽  
Mix Proportion ◽  
Gypsum Plaster ◽  
Bone Glue

FGD gypsum-fly ash plaster material was prepared by desulfurization gypsum plaster and fly ash as main materials, compound retarder A (composed of citric acid, sodium metaphosphate and borax), methylcellulose (MC) as super absorbent polymers (SAP) and water reducing agent of lignosulfonate. Mix proportion was determined through studying effects of the experimental factors, including fly ash mixing amount, retarders of citric acid, bone glue and compound retarder A, and SAP of MC and dextrin, on plaster material properties. Final mix proportion was followed as: FGD gypsum to fly ash mass ratio of 4.0, compound retarder of 0.2%, methylcellulose of 0.2% and lignosulfonate of 0.1%.

Activation of rejected fly ash using flue gas desulphurization (FGD) sludge

2003 ◽  
Vol 18 (4) ◽  
pp. 84-88 ◽  
Author(s):  
Qiao Xiu-chen ◽  
Poon Chisun ◽  
Lin Zong-shou
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Flue Gas Desulphurization

Fly Ash-Desulfurization Gypsum Mortar and Concrete Part I: Mix Proportions and Hydration

2011 ◽  
Vol 250-253 ◽  
pp. 809-816
Author(s):  
Yu Chen ◽  
Ying Li Gao
Keyword(s):  
Fly Ash ◽  
Flue Gas ◽  
Hydration Process ◽  
Cement Stone ◽  
Composite Binder ◽  
Strength Concrete ◽  
Concrete Hydration ◽  
Concrete Part ◽  
Flue Gas Desulphurization

Fly ash (FA) and flue gas desulphurization gypsum (FGD) were blended in proportion into a new composite binder added with cement, lime and some modifiers. In the paper, the mix proportions of composite binder with low-quality FA and FGD were studied. FA-FGD more than 80% with FA:FGD 3:2 was suggested for mortar, plastering and slurry while FA:FGD 2:1 and FA-FGD 30~40% was recommended for middle-strength concrete. Hydration process of typical mixtures of FA-FGD paste was investigated through SEM and XRD tests. The conclusion could be made that FA showed much improved pozzolana activity especially at early ages due to the existence of FGD as an ideal sulfate activator, which also crystallized later to strengthen the hardened paste. The microstructure of hydrated FA-FGD paste was more excellent than that of neat cement stone or one blended with the same percentage of pure FA.

scholarly journals Performance of Self-compacting Concrete with Stainless Steel Slag Versus Fly Ash as Fillers: A Comparative Study

2021 ◽  
Author(s):  
Yeong-Nain Sheen ◽  
Duc-Hien Le ◽  
My Ngoc-Tra Lam
Keyword(s):  
Stainless Steel ◽  
Compressive Strength ◽  
Fly Ash ◽  
Setting Time ◽  
Steel Slag ◽  
Strength Loss ◽  
Comparative Investigation ◽  
Self Compacting Concrete ◽  
Stainless Steel Slag ◽  
Initial Setting Time

Recently, stainless steel slag -a byproduct of manufacturing stainless steel is accepted as a cementitious material, the chemical characteristics of which are highly variant. This study reuses two types of stainless steel reducing slag with specific surface area of 1766 cm2/g (S1) and 7970 cm2/g (S2) in developing self-compacting concrete (SCC). Particularly, two S2-blended SCCs incorporating with S1 and fly ash as fillers (calling as S-mix and F-mix) were prepared for a comparative investigation. In both SCCs, ordinary Portland cement was replaced by S2 with various ratios (from 0 % to 50 %, increment 10 %). Testing results show that in fresh state, the F-mix exhibits higher workability and longer initial setting time than those of S-mix. In hardened state, 10 % compressive strength loss was realized as increasing S2 content up to 30 % in the both SCCs; the strength of F-mix is up to 1.9 times of S-mix at the same rate of S2 replacement. Water absorption of the F-mix was below 3 %, suggested as a “good” quality concrete; whilst the S-mix could be longs to an “average” one. Resistivity and sulfate resistance of F-mix are considerably higher than those of S-mix. Moreover, based on the obtained data, compressive strength and electrical resistivity are correlated well with a logarithmic form.

scholarly journals Effects of Fluorogypsum and Flue-Gas Desulfurization Gypsum on the Hydration and Hardened Properties of Alkali Slag Cement

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1475
Author(s):  
Cheng Wang ◽  
Hang He ◽  
Yuli Wang ◽  
Wenyue Xue
Keyword(s):  
Flue Gas ◽  
Setting Time ◽  
Control Sample ◽  
Heat Of Hydration ◽  
Flue Gas Desulfurization ◽  
Slag Cement ◽  
Fgd Gypsum ◽  
Gypsum Content ◽  
Waste Gypsum ◽  
The Difference

In order to explore the influence of the types of waste gypsum on the properties of alkali slag cement, fluorogypsum (FG) and flue-gas desulfurization (FGD) gypsum were comparatively investigated. Moreover, the action mechanisms of FG and FGD gypsum on the properties of alkali slag cement were analyzed. The results show that both the FG and FGD gypsum prolonged the setting time of the alkali slag cement paste. However, the prolongation effect of FG was more pronounced than the FGD gypsum. When the compressive strength was maximum, the contents of FG and FGD gypsum were 5 and 6 wt.%, respectively. At 3 and 28 days, compared to the control sample, the compressive strengths increased by 59.3% and 24.3%, and 66.9% and 33.9%, respectively. Furthermore, the XRD, TG-DTA and SEM-EDS results showed that, with the increase in the contents of FG and FGD gypsum, ettringite was more easily produced and the hydration products were more abundant in the system. The greater the gypsum content of the paste, the less accumulated was the heat of hydration. The change of micro-structure caused by the formation of ettringite was the main reason for the difference in the properties of cement.

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