Fast in-situ X-ray scattering reveals stress sensitivity of …

The dehydration of gypsum to hemihydrate has been studied for decades because it is an important model reaction for understanding fluid-triggered earthquakes, …

The Ultimate Guide to Dehydrating Food

For a lower cost, vertical flow machine, the N Snackmaster FD-75A is a great option if you're just getting started but don't want to make a big investment just yet. This is the model we used for our first couple of years of dehydrating. It has variable temperature settings (95F-160F), is BPA free, allows us to change the number of trays …

The thermal dehydration of synthetic gypsum

Mass losses vary between 13.7 and 16.5% and heat of dehydration values between 377 and 420 J g −1 for the dehydration of ground and mixed inhomogeneous gypsum samples. As for the dehydration of CaSO 4 ·2H 2 O, the dehydration of synthetic gypsum proceeds via multi-step reactions. Using a heating rate of 5°C min −1, the very …

Gypsum: Properties, Uses, Formation, Types – …

How is Gypsum Formed? Gypsum forms through two primary geological processes: Evaporative Precipitation: This process occurs in environments with high evaporation rates, such as shallow marine environments, …

Formation of α-Hemihydrate Inside of a Gypsum Crystal …

This subhydrate material is mixed with water at a construction site to form dihydrate (gypsum) again. Therefore, the dehydration process of gypsum and the rehydration of hemihydrate were investigated in several studies; the given references will give an overview of the research conducted up to now [3,4,5,6,7,8,9,10,11,12,13,14,15]. …

The thermal dehydration of synthetic gypsum

Using the temperature values at different a-values for different heating rates (0.5 min-' < < 5 min-'), Fig. 2 (activation energy E vs. a) is obtained for the dehydration reactions of gypsum up to 180. From the figure it is clear that the dehydration reactions do not occur in single steps. At least three stages in the dehydration can be observed.

Experimental VNIR reflectance spectroscopy of gypsum …

The spectral behavior of gypsum dehydration in the visible to near-infrared (350–2500 nm) wave - length range was investigated by partially dehydrating the four main habits of gypsum (alabaster, satin spar, selenite, and massive) to form bassanite. Powdered samples of gypsum dehydrated at 100–115 °C and hand samples dehydrated at …

The dehydration process of gypsum under high pressure

The effects of pressure on the dehydration of gypsum materials were investigated up to 633 K and 25 GPa by using Raman spectroscopy and synchrotron X-ray diffraction with an externally heated diamond anvil cell. At 2.5 GPa, gypsum starts to dehydrate around 428 K, by forming bassanite, CaSO4 hemihydrate, which completely …

Dehydration‐induced damage and deformation in gypsum …

This estimation ensures that the seismic tomography signature of dehydrating gypsum in nature is expected to be a decrease in effective Poisson's ratio. Figure 13. ... [51] As stated in section 1, Volterra gypsum has been chosen as a low-temperature analogue of serpentinites. The extrapolation of our observations on …

Gypsum hydration: a theoretical and experimental study

gypsum. The measured hydration time is much shorter than value from /7/ with electrical resistance method. This probably can be explained by the difference between microstructure of used materials which also indicates its influence on hydration. 2750 0 250 500 750 1000 1250 1500 1750 2000 2250 2500 1,0E-4 1,0E-9 1,0E-8 1,0E-7

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 …

How to dehydrate in an oven

In this case, you might want to consider leaving the door slightly open to get a cooler temperature. Your total dehydration time is going to be a lot shorter than the recipes states for a dehydrator, so you'll need to keep an eye on it. You have a fan assisted oven that goes down to 116F / 47C.

Does Alcohol Dehydrate You? Here's What You Need to …

How much alcohol does it take to dehydrate you? How much alcohol it takes to dehydrate you depends on factors such as your gender, body composition, and overall health status. It's generally believed that for every gram of alcohol consumed, the kidneys produce around ten milliliters of urine, which increases fluid loss and contributes …

Gypsum | Properties, Formation, Uses and Deposits

1. Hardness:Gypsum is a relatively soft mineral on the Mohs scale of mineral hardness, with a hardness rating of 2. This means that it can be easily scratched with a fingernail or a pocket knife. Its...
2. Color:The color of gypsum can vary depending on impurities present in the mineral. It is commonly found in shades of white, gray, or colorless. However, it can also exhibit colors su…

1. Hardness:Gypsum is a relatively soft mineral on the Mohs scale of mineral hardness, with a hardness rating of 2. This means that it can be easily scratched with a fingernail or a pocket knife. Its...
2. Color:The color of gypsum can vary depending on impurities present in the mineral. It is commonly found in shades of white, gray, or colorless. However, it can also exhibit colors such as brown, pi...
3. Transparency:Gypsum crystals can be transparent to translucent, allowing light to pass through them in varying degrees. The level of transparency depends on the crystal's quality and the presence o...
4. Cleavage:Gypsum exhibits excellent cleavage in one direction, meaning it readily splits into t…

(PDF) Scrutinizing Gypsum Board Thermal Performance at Dehydration

This article investigates the thermal performance of gypsum boards in the dehydration temperature region, where pronounced chemical reactivity is anticipated. Gypsum board samples were gradually ...

Dehydrating Food: Beginner's Guide

Although many skip this step for jerky-making, instead opting for curing over cooking, for all other meats it is recommended they be cooked to an internal temperature of 160°F before dehydrating (and 165°F for poultry). When dehydrating, a constant temperature of 130°F to 140°F (54°C to 60°C) must be maintained according to Ask …

FGD Gypsum Production Process

Mineralogically identical to natural gypsum, FGD gypsum, or synthetic gypsum, is produced from gas captured within emission control systems at coal fired electric utilities. An emission that would compromise air quality, sulfur dioxide (SO2) gas, is the primary contribution coal makes to FGD gypsum. Utilities that produce panel-grade synthetic …

From atom level to macroscopic scale: Structural mechanism of gypsum

1. Introduction1.1. General context. Gypsum plaster is an inorganic binder that is prepared in a two-step process. The first step is dehydration: heated to 100–200 °C, gypsum (CaSO 4 ·2H 2 O) releases water as vapor [1, 2] and, depending on temperature and water vapor partial pressure (p H2O) [3, 4] forms either hemihydrate (CaSO 4 •½H 2 …

Moisture transport and dehydration in heated gypsum, an …

1. Introduction. The question of how a porous building material responds to a fire is one of the main questions in fire safety. During a fire, a building material can suddenly be heated up to temperatures of approximately 1000 °C.At temperatures above 100 °C water inside the pores will start to boil.Simultaneously, in materials such as …

Structural evolution during the dehydration of gypsum …

Mineralogical Magazine, June 2009, Vol. 73(3), pp. 421–432 Structural evolution during the dehydration of gypsum materials S. D. M. JACQUES1,*, A. GONZÁLEZ-SABORIDO1, O. LEYNAUD1, J. BENSTED1, M. TYRER2, R. I. W. GREAVES2 AND P. BARNES1 1 Department of Chemistry, University College London, 20 Gordon Street, …

What Temperature to Dehydrate Beef Jerky | Dehydrator Temperature

The good news is that if you're wondering what temperature to dehydrate beef jerky at, you've come to the right place. We've been smoking meats for over 100 years and are proud of our reputation as the go-to source for the best beef jerky online. We'll cover the factors influencing your optimal dehydrator beef jerky temperature and

Dehydrating Time & Temperature Guide: Fruits, Vegetables, Meat…

The dehydrating temperature for jerky ranges from 160 to 165 degrees F. Item: Temperature: Dehydrating Time: Meat and Poultry Jerky: 160-165 degree F: 4-6 hours: Fish Jerky: 160-165 degree F: 12-14 hours: Fruit Leather Dehydrating Time and Temperature. Fruit leather is made from drying thin layers of fruit puree in a dehydrator. …

Gypsum: a review of its role in the deterioration of

the-art review on gypsum and its related compounds. He highlights the fact that the kinetics of the dehy-dration of gypsum to hemihydrate is slow. To initiate a relatively fast reaction a temperature of 120 C is re-quired, though dehydration will continue even at lower temperatures as long as it does not fall below 107 C. A

(PDF) Dehydration Pathways of Gypsum and the …

The thermodynamic calculation results reveal that the dehydration mechanism of gypsum significantly depended on ambient temperature and water vapor pressure.

Gypsum: a review of its role in the deterioration of building …

The curve of the hemihydrate solubilities is largely based on the data of Partridge and White (), Posnjak (), D'Ans et al. and Power et al. yielding a gypsum to hemihydrate transition temperature of 99 ± 4°C, which is in reasonable agreement with the values of 97.5°C (Posnjak 1938) and 97°C (D'Ans et al. 1955).According to Fig. 2 the …

The dehydration process of gypsum under high …

formation from gypsum to bassanite to anhydrite represents steps of a progressive dehydration process (Chang et al. 1996; Putnis et al. 1990; Ballirano and Melis 2009). Other studies (Prasad et al. 2001, 2005) questioned the direct formation of bassanite from dehydration of gypsum and indicated that it may form by rehydration from c-anhydrite

Influence of the Calcination Temperature of Synthetic Gypsum …

Possible transformations of the dehydration and hydration of synthetic gypsum in the calcination process [23]. …

Anhydrite and gypsum

Anhydrite (CaSO 4) and gypsum (CaSO 4 ·2H 2 O) are the two most abundant minerals of ancient marine evaporite deposits and are also common in non-marine evaporite deposits. Sedimentary gypsum forms by direct precipitation out of evaporating seawater under arid climatic conditions in hydrologically restricted marine …

From atom level to macroscopic scale: Structural mechanism …

Abstract. Plaster, made of calcium sulfate hemihydrate (CaSO 4 •½H 2 O) and/or γ -anhydrite (CaSO 4) is obtained by dehydration of gypsum (CaSO 4 ·2H 2 O) at …