Changes in structure and composition of gypsum paste at …
The structure and composition of the gypsum at elevated temperatures were studied by means of scanning electron microscopy, X-ray diffraction (XRD) and thermogravimetry (TG). The gypsum paste samples were heated to the temperatures from 50 to 1000 °C. The changes in the structure of gypsum were in good accordance with …
Experimental Studies on Decomposing Properties of …
Due to microwave heating and calcium ferrite formation, the decomposition temperature of FGD gypsum decreased to around 800°C in air atmosphere. Based on the XRD patterns and SEM images, the ...
Study of gypsum by PDSC | Journal of Thermal Analysis and …
Thermal decomposition of gypsum is very dependent on the experimental conditions such as particle size of the sample, atmosphere, heating rate. ... The highest …
Fate of mercury in flue gas desulfurization gypsum …
Besides, it could be reasonably expected that mercury in FGD gypsum might be released in the gas phase during the calcination process of wallboard production, based on the release curves of FGD gypsum samples from TPD, even though the temperature in the industrial process (about 160°C) is lower than the peak temperature of the …
Gypsum plaster waste recycling: A potential environmental …
Gypsum plaster is considered a sustainable binder, produced by the calcination of gypsum (calcium sulfate dihydrate: CaSO4∙2H2O) in a dry process at temperatures that range from 125 °C to 180 °C (Borrachero et al., 2008; Gartner, 2009).
Influence of Carbon and Pyrite on Desulfurization Behavior …
The iron and calcium elements can be reused as iron-making raw materials, but the sulfur element in the gypsum is required to be removed as it has a harmful effect on the properties of iron. Herein, the influence of carbon and pyrite on the desulfurization behavior of red gypsum is systematically investigated by high-temperature decomposition.
Utilization of Desulfurization Gypsum to Producing SO
However, in the reducing atmosphere with different CO content, the CaSO 4 begin to decompose at temperature about 800°C, which was much lower than that of the pure …
Utilization of Desulfurization Gypsum to Producing SO
However, in the reducing atmosphere with different CO content, the CaSO 4 begin to decompose at temperature about 800°C, which was much lower than that of the pure reactive CaSO 4, about 970°C .The reason is the impurities in the phosphogypsum, such as SiO 2, Al 2 O 3 and Fe 2 O 3, reacts as catalyst to reduce the initial decomposition ...
Fate of mercury in flue gas desulfurization gypsum …
In this study, Temperature Programmed Decomposition (TPD) and Sequential Chemical Extraction (SCE) were applied to FGD gypsum to identify the Hg species in it. The FGD gypsum samples were collected from seven coal-fired power plants in China, with Hg concentrations ranging from 0.19 to 3.27μg/g.
Fate of mercury in flue gas desulfurization gypsum …
Zhu et al. [20] used temperature programmed decomposition and sequential chemical extraction method to explore the fate of mercury in FGD gypsum, which concluded that mercury was mainly retained ...
Thermal decomposition of gypsum
Abstract. The decomposition of CaSO 4 · 2H 2 O under the conditions of TA consists of two consecutive reactions, firstly CaSO 4 · 0.5H 2 O then CaSO 4 III being …
Gypsum plasterboards under natural fire
the application of temperature-dependent thermal properties under natural fire especially for the cooling phase. 2 | STATE OF THE ART 2.1 | Thermal decomposition of gypsum …
Fate of mercury in flue gas desulfurization gypsum …
Fate of mercury in flue gas desulfurization gypsum determined by Temperature Programmed Decomposition and Sequential Chemical Extraction Zhu, Z.; Zhuo, Y.; Fan, Y.; Wang, Z. Journal of Environmental Sciences 43: 169-176
New insight into the phase changes of gypsum
The temperature at which the gypsum binder (calcium sulfate hemihydrate) is industrially produced, between 80 and 180 °C, is often mentioned in the literature [14,15,16,17].However, dehydration from gypsum to basanite (CaSO 4 ·0.5H 2 O) starts at a much lower temperature. The dehydration temperature depends on the …
Thermal decomposition of gypsum
Semantic Scholar extracted view of "Thermal decomposition of gypsum" by F. Paulik et al. ... with limited oxygen and argon studies at the same temperature. … Expand. 9. Save. Investigations under quasi-isothermal and quasi-isobaric conditions by means of the Derivatograph.
Show the decomposition of gypsum to P.O.P and back …
$$text{The decomposition of gypsum to Plaster of Paris is as follows:-}$$ $$ 373,K $$ $$ CaSO_4. 2H_2O xrightarrow{bigtriangleup} CaSO_4 . 1/2H_2O $$
Reductive decomposition of waste gypsum with SiO2, …
From the point of view of a sustainable and environment-friendly society based on the recycling of material resources, it is preferable to utilize waste gypsum as a substitute for lime, which is currently produced by the calcination of limestone. In the present work, the reductive decomposition of CaSO4 was investigated under an …
Thermal Analysis of Gypsum
It is important to know the characteristics of gypsum before using it. The thermal characteristics of gypsum produce the following thermal changes. 60~150°C …
Fate of mercury in flue gas desulfurization gypsum …
Semantic Scholar extracted view of "Fate of mercury in flue gas desulfurization gypsum determined by Temperature Programmed Decomposition and Sequential Chemical Extraction." by Zhen-wu Zhu et al. ... {Zhu2016FateOM, title={Fate of mercury in flue gas desulfurization gypsum determined by Temperature Programmed …
Influence of Carbon and Pyrite on Desulfurization …
till the sintering temperature of 1200 °C; however, the decomposition rapidly proceeded at T > 1250 °C. However, the initial decomposition temperature of CaSO 4 is reduced by 20–50 °C and decomposition was complete before 1300 °C after the addition of Fe 2 O 3 [11]. Herein, despite the presence of Fe 2 O 3
Recovery of CaO from CaSO4 via CO reduction decomposition …
The direct decomposition temperature of CaSO 4 is extremely high (Dewing and Richardson, 1959; Liu et al., 2007), which causes a severe sintering of CaO, resulting in the reduced activity of CaO ... It was discovered that the reaction efficiency of gypsum decomposition was high between 1050 °C and 1075 °C.
Reaction mechanism of reductive decomposition of FGD gypsum …
Comparing the TG curves in Fig. 3, it seems that there was a considerable change in the starting temperature of the decomposition reaction of the FGD gypsum with addition of anthracite that took place at 670 °C. Therefore, addition of carbon caused the decomposition reaction to proceed at lower temperature.
Thermal decomposition of limestone and gypsum by solar …
This would tend to increase the decomposition temperature[7]. Such problems can be avoided by using a fluidized bed reactor, where temperature homogenit.v and high mass and heat transfer rates can be obtained. 3.2 Gypsum decomposition Gypsum (CaSO~. 2H20) becomes anhydrous at temperatures above 160: CaSOa" …
Reductive Decomposition of Gypsum by Carbon Monoxide
High-Temperature Release of SO2 from Calcined Cement Raw Materials. Energy & Fuels 2011, 25 (7) ... Insight into the reaction characteristics of H2-reduction decomposition of gypsum: Experimental and isothermal kinetic analysis. International Journal of Hydrogen Energy 2024, 49, 1344-1360.
Influence of Carbon and Pyrite on Desulfurization Behavior …
Herein, the influence of carbon and pyrite on the desulfurization behavior of red gypsum is systematically investigated by high-temperature decomposition. In the absence of carbon, a small amount of anhydrite (CaSO4) phase is decomposed after sintering at 1200 °C for 2 h.
Reductive decomposition of waste gypsum with SiO 2, Al …
Due to microwave heating and calcium ferrite formation, the decomposition temperature of FGD gypsum decreased to around 800°C in air atmosphere. Based on the XRD patterns and SEM images, the ...
Gypsum content determination in Portland cements by thermogravimetry
Due to the above chemical properties, the decomposition of gypsum occurs at higher temperature ranges than plaster of Paris or hemihydrate samples. For the former, at high heating rates, decomposition occurs from 100 to about 300 °C, with overlapped peaks of the two steps .
Effect of high temperatures on gypsum paste and mortar
This paper describes the influence of high temperatures on some physical and mechanical properties of gypsum mixtures. Two gypsum mixtures were designed, first one was composed of gypsum and citric acid and the second one contained standardized sand also. The samples were exposed to temperatures from 50°C to 1000°C.
Reaction mechanism of reductive decomposition of FGD gypsum …
The process of decomposition reaction between flue gas desulfurization (FGD) gypsum and anthracite is complex, which depends on the reaction conditions and atmosphere. In this study, thermogravimetric analysis with Fourier transform infrared spectroscopy (TGA-FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) …
Thermal decomposition of gypsum
Coordinated disposal of FGD gypsum and power plant concentrated brine via preparation of α-hemihydrate gypsum. Materials Today Sustainability, Volume 25, 2024, Article 100644 ... Kinetic model for calcium sulfate decomposition at high temperature. Transactions of Nonferrous Metals Society of China, Volume 25, Issue 10, 2015, pp. …