The most prevalent sulfate mineral in the surrounding natural environment is calcium sulfate, which can be found as calcium sulfate dihydrate or gypsum (CaSO 4 ⋅2H 2 O), hemihydrate (CaSO 4 ⋅ ...
Calcium sulfate dihydrate (gypsum) loses its water of hydration when exposed to an environment with sufficiently low vapor pressure. At temperatures higher …
When deposited from concentration of sea water, gypsum (CaSO 4 ·2H 2 O) precipitates out first, followed by the deposition of anhydrite (CaSO 4) as the salt concentration increases. Both gypsum …
Phosphogypsum is a by-product of phosphoric acid production by a wet-process and can be used to prepare adsorption materials to treat Cd(ii) in sewage. Its main component is calcium sulfate dihydrate (gypsum). In the present study, incorporation and adsorption of cadmium on gypsum in an aqueous environment h
Gypsum is an evaporite mineral most commonly found in layered sedimentary deposits in association with halite, anhydrite, sulfur, calcite, and dolomite. Gypsum (CaSO 4. 2H 2 O) is very similar to Anhydrite (CaSO 4). The chemical difference is that gypsum contains two waters and anhydrite is without water. Gypsum is the most common sulfate mineral.
Fig. 1 shows the XRD pattern of FGD gypsum raw materials, which indicates that the main phase of FGD gypsum is calcium sulfate dihydrate. The morphology of FGD gypsum is given in Fig. 2.As illustrated in Fig. 2 a, the FGD gypsum has large particles with an average particle size distribution of about 60 μm. Fig. 2 b clearly reveals that …
To recognize the effect of impurities on the gypsum habit, the impurity-free gypsum habit must be known. This is often reported in the literature by mixing calcium chloride dihydrate (CaCl 2 ·2H 2 O) or calcium nitrate (Ca(NO 3) 2) with sodium sulfate (Na 2 SO 4) to produce supersaturated solutions with respect to calcium sulfate dihydrate …
Abstract The dehydration of gypsum CaSO4.2H2O has been studied, at negligible water vapour pressure, by in situ infrared (IR) spectroscopy and by thermogravimetry to determine whether intermediate phases (CaSO4.nH2O) exist, other than the hemihydrate with n=0.5, and also to compare the mechanism of the dehydration …
The axial development of calcium sulfate dihydrate (gypsum) scaling on selected reverse osmosis (RO) membrane surfaces was investigated experimentally in a plate-and-frame RO system. ... The above results suggest that retentate filtration essentially eliminate gypsum crystal scale formation by deposition of bulk crystals. Clearly, with ...
The bulk deposition of the industrial by-product gypsum causes severe environmental pollution and the increasing cost of land. How to reuse the huge amounts of by-product gypsum has become an urgent problem for the government. Since the last century, the preparation of α-HH with high-value added,
Gypsum occurs in extensive beds associated with other evaporite minerals (e.g., anhydrite and halite), particularly in Permian and Triassic sedimentary formations; it is deposited from ocean brine, followed by anhydrite and halite.It also occurs in considerable quantity in saline lakes and salt pans and is an important constituent of cap rock, an anhydrite-gypsum …
Its main component is calcium sulfate dihydrate (gypsum). In the present study, incorporation and adsorption of cadmium on gypsum in an aqueous environment have been investigated using dispersion-corrected density functional theory, and the effect of different vacancy defects on the adsorption and doping of Cd on gypsum was also studied.
The results show that the main components of natural gypsum minerals were gypsum dihydrate (71%), dolomite (27%) and potassium chloride (2%). The hydration …
The most prevalent sulfate mineral in the surrounding natural environment is calcium sulfate, which can be found as calcium sulfate dihydrate or gypsum (CaSO 4 ·2H 2 O), hemihydrate (CaSO 4 ·½H 2 O), and anhydrite (CaSO 4). All of these forms have the ability to be crystallized in the presence of water [11,12].
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 …
Gypsum (CaSO4·2H2O) is the most common sulfate mineral on Earth and is also found on Mars. It is an evaporitic mineral that predominantly precipitates from brines. In addition to its precipitation in natural environments, gypsum also forms an undesired scale in many industrial processes that utilize or produce brines. Thus, better insights …
The predicted gypsum solubilities show excellent agreement with the experimental data for the temperature range of 25 to 80 °C and pressures up to 1,000 bar with NaCl concentration up to 5 M. The method is simple, compact, and reliable and can be applied to any environment where gypsum is expected to precipitate.
Typically, to produce drywall, manufacturers must first dehydrate mined gypsum into bassanite, a time- and energy-intensive process. The study concludes by explaining that learning how gypsum …
The changes from gypsum to anhydrite and back to gypsum are common processes (Klimchouk, 2000). This way, James (1992) noted that in very hot climates gypsum can dehydrate to anhydrite when it is ...
Deposits of gypsum resulted from a combination of direct, in situ alteration of sulfide- and high-calcium-pyroxene-bearing dunes and from formation of evaporitic gypsum crystals in the pore spaces of these …
In order to achieve the resourceful, large-scale and high-value utilization of bulk industrial solid wastes such as flue gas desulfurization gypsum (FGDG), fly ash (FA) and ground blast furnace slag (GGBS), and to reduce the dosage of cementitious materials, orthogonal experimental methods were used to prepare composite cementitious …
Gypsum. Gypsum is a mineral found in crystal as well as masses called gypsum rock. It is a very soft mineral and it can form very pretty, and sometimes extremely large colored crystals. Massive gypsum rock …
in the study of gypsum and anhydrite beds, for if estimates of the depth of burial, temperature, and concentration of ground water solutions can be made for these …
Calcium sulfate exists in three forms, namely dihydrate or gypsum (CaSO4·2H2O), anhydrite (CaSO4), and hemihydrate or bassanite (CaSO4·0.5H2O) depending on temperature, pressure, pH, and formation conditions. The formation of calcium sulfates occurs widely in nature and in many engineering settings. Herein, a …
Phosphogypsum is a by-product of phosphoric acid production by a wet-process and can be used to prepare adsorption materials to treat Cd(II) in sewage. Its main component is calcium sulfate dihydrate (gypsum). In the present study, incorporation and adsorption of cadmium on gypsum in an aqueous environment have been investigated …
Calcium sulfate is widely found in the Earth's crust, in areas such as deserts, lakes and oceans [1,2].Calcium sulfate has three crystalline polymorphs that differ in their degree of hydration, including dihydrate (CaSO 4 ·H 2 O, gypsum), hemihydrate (CaSO 4 ·0.5H 2 O, bassanite) and anhydrite (CaSO 4) [3,4,5,6].Among these polymorphs, …
Why Gypsum is Fire Resistant. Gypsum is strong against fire. The secret is in crystallized water equivalent to about 21% of its weight. This crystallized water is very stable in normal condition and does not disperse, but once it comes in contact with the heat of fire it will cause thermal decomposition and start to evaporate. The temperature of gypsum does …
Gypsum is a naturally occurring mineral composed of calcium sulfate dihydrate. It's used in agriculture and s? Gypsum improves soil structure by reducing compaction in heavy clay soils, enhancing water penetration and …
The axial development of calcium sulfate dihydrate (gypsum) scaling on selected reverse osmosis (RO) membrane surfaces was investigated experimentally in a plate-and-frame RO system. ... The above results …
Gypsum, a soft sulfate mineral known as calcium sulfate dihydrate, has been used for centuries as a reliable soil amendment to improve soil structure, enhance water infiltration, and reclaim saline and sodic soils. ... Sustainability and Environmental Impact. Gypsum is an environmentally friendly soil amendment. As a natural mineral, it …
Geologists analyze sedimentary rock facies to interpret the original deposition environment, as well as disruptive geological events that may have occurred after the rock layers were established. It boggles the imagination to think of all the sedimentary deposition environments working next to each other, at the same time, in any particular ...
Gypsum deposits are found in many parts of the world, with varying degrees of purity and abundance. These deposits occur in a variety of geological settings, reflecting the diverse conditions under which gypsum forms. Here are some notable locations and types of gypsum deposits: 1. …
Gypsum is widely used in the construction sector, and its worldwide consumption has been increasing for several decades. Depending on the lifetime of the used gypsum products, an increase of gypsum in construction and demolition waste follows. Especially against the background of a circular economy, the recycling of waste …
