At high temperatures, gypsum dehydrates to other calcium sulfate phases ... Figs. 3, 5) showed a significant mass decrease caused by the decomposition of anhydrite at temperatures between 1100 and 1500 °C, when calcium oxide and sulfur oxide are products of the reaction. The occurence of free lime was also proved by the …
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 …
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. …
Gypsum at High Temperature Xiaoling Ma1 · Hongbin Tan1 · Faqin Dong2 · Feihua Yang3 Received: 17 August 2021 / Accepted: 8 December 2021 / Published online: 3 February 2022 ... desulfurization behavior of red gypsum is systematically investigated by high-temperature decomposition. In the absence 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 ...
The dehydration temperature depends on the measurement method, the gypsum origin (natural, FGD), the type of required calcium sulfate hemihydrate (α, β), …
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.
No decomposition occurred at 114°C but complete decomposition to a mixture of gypsum and hemihydrate, together with amorphous material, occurred at 120°C. Upon stepwise reduction of temperature to 115°C, some reformation of ettringite occurred together with hemihydrate, while nearly complete reformation of ettringite occurred at …
As mentioned earlier, the anhydrite decomposition depends on the reaction temperature and the CO concentration. 14, 15 One should note that the impurity phases in PG, including SiO 2 and Al 2 O 3 ...
Previous studies have also concluded that the decomposition of gypsum and ettringite and the dehydration of some carbo aluminate hydrates occur in the temperature range of 60-200 • C.
Gypsum is a naturally occurring mineral that has been used by humans for various purposes for thousands of years. It is a versatile mineral with a wide range of applications in construction, agriculture, …
transition from hemihydrate gypsum to crystalline gypsum (dihydrate gypsum). This brief presents examples of TG/DTA and DSC measurements of the thermal changes of gypsum.
bed of gypsum 1 inch thick, was sus- pended inside the preheated furnace, and as its temperature rose, a mixture of sul- fur dioxide and air was passed through to prevent the gypsum from decomposing. As operating temperature was ap- proached, nitrogen and carbon dioxide were added. When the reactor tempera-
So, the decomposition of gypsum occur at ${text{120}}{,^{text{o}}}{text{C}}$ to give P.O.P and back interconversion of P.O.P to gypsum is take place by treating the P.O.P with water. ... The temperature of heating is important because heating gypsum at different temperatures leads to the formation of …
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.
Concerning the thermal stability of ettringite crystals, many studies have suggested that the decomposition temperature of ettringite is generally considered to be 70–80 °C ... (CaSO 4 ·2H 2 O, hemihydrate gypsum, hard gypsum, etc.) at room temperature reacts with C 3 A hydration to form ettringite, which will later be converted …
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" …
The formation of beta-hemihydrate starts at around 85°C and is shifted into the formation of anhydrite III. Due to this, it is tricky to measure the mass loss of wet …
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 plasterboards In general, gypsum plasterboards consist of a porous solid core of primar-ily calcium sulfate dihydrate CaSO 4 2H 2O between two layers of paper.
During a test, the furnace temperature is either kept constant or increased at a fixed rate (typically between 1 and 60 °C/min) to predefined maximum temperature (routinely 1000 °C or higher). The heating rate affects the rate of thermal decomposition of a material and a faster heating rate tends to push the mass loss curve to higher ...
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 ...
This paper proposes a catalyst to lower the decomposition temperature of phosphogypsum (PG) and investigates the reaction mechanism. PG is stable in the inert atmosphere, decomposed above 1100 °C ...
$$text{The decomposition of gypsum to Plaster of Paris is as follows:-}$$ $$ 373,K $$ $$ CaSO_4. 2H_2O xrightarrow{bigtriangleup} CaSO_4 . 1/2H_2O $$
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.
In this work, we have reinvestigated the thermal degradation kinetics of synthetic gypsum (CaSO 4 ·2H 2 O) using a novel approach based on peak deconvolution followed by the application of Model-Free isoconversional method. Gypsum was prepared using wet chemical route and characterized by conventional X-ray diffraction, in situ high …
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).
The results indicated that the factors of the final reaction temperature and the reaction atmosphere have significant influences on the decomposition of gypsum, in the condition of 850–1,050°C, the total decomposition rate of three gypsums increases and the time-consumption of reaching decomposition equilibrium of three gypsums …
With the addition of gypsum (CaSO 4 ·2H 2 O), the initial decomposition temperature decreased slightly relative to that of EPS/HFR0 due to dehydration of the gypsum to form thermally stable ...
Decomposition of gypsum was incomplete after heating in air at 1180°C, whereas calcium ferrite was successfully obtained by a two-step heat treatment of gypsum: forming CaS …
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 …
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