Mechanism of water extraction from gypsum rock by desert …

Structure and chemistry of gypsum rocks sample from the Atacama Desert. (A) Optical microscopy of a thin cross-section of the gypsum sample with black impurities within the rocky matrix.(B) Energy-dispersive X-ray (EDX) mapping on gypsum rock samples.The mapping area is indicated with red box in A.The white area is gypsum, while the black area shows Si, Al, Mg, O, …

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Green approach for low-energy direct synthesis of anhydrite …

The proposed technology consists in obtaining gypsum or anhydrite in a one-stage process from industrial waste. As a source of calcium carbonate in the project, it is proposed to …

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Dissolution and conversions of gypsum and anhydrite

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 ...

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The anhydrite surface – cause of problems in tunnel …

It is generally known that the transformation of anhydrite/gypsum due to the absorption of H2O causes an increase of volume of approximately 60% and that its restraint results in the build-up of swelling pressure up to 6-7 MPa (confirmed by laboratory experiments), see Fig. 1.

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High Strength Anhydrite Cement Based on Lime Mud From …

Since the synthesis of anhydrite was carried out in the same way as the synthesis of gypsum in the (CaO·Ca(OH) 2 ·CaCO 3)—H 2 SO 4 —H 2 O system, it was found that an increase in particle size has a positive effect on the properties of anhydrite cement obtained from synthetic anhydrite.

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Gypsum/anhydrite: some engineering problems

Abstract The engineering properties of gypsum/anhydrite change as a consequence of groundwater, pressure and heat. Gypsum and anhydrite may experience dissolution in the near-surface zone and along the discontinuities, creating karst terrain to depths related to present and/or past groundwater levels. This paper reviews the problems of constructing on …

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Gypsum/anhydrite: some engineering problems

L'article analyse les difficultés techniques liées à la construction sur les formations de gypse ou d'anhydrite et présente quelques courtes études de cas pour illustrer certains des …

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The Solubilities and Thermodynamic Equilibrium of Anhydrite and Gypsum

Anhydritic claystones consist of a clay matrix with finely distributed anhydrite. Their swelling has led to severe damage and high repair costs in several tunnels. Gypsum growth combined with water uptake by the clay minerals is the main cause of the swelling process. Identifying the conditions under which gypsum rather than anhydrite represents the stable …

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Chapter 16 Geohazards caused by gypsum and anhydrite in …

Gypsum is hydrated calcium sulphate CaSO 4 · 2H 2 O, the dehydrated form being anhydrite CaSO 4.Gypsum is the most common form found in modern evaporitic sedimentary environments (such as sabkhas in the Gulf; Kendall & Alsharhan 2011), but upon burial it dehydrates to anhydrite.This dehydration generally occurs at depths of between 450 m (Klimchouk & …

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Geochemical and engineering aspects of anhydrite/gypsum …

Title: Geochemical and engineering aspects of anhydrite/gypsum phase transitions Author(s): Zanbak, Caner Arthur, Randolph C. Affiliation: Woodward-Clyde Consult., Chicago, IL, United …

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Geochemical and engineering aspects of anhydrite/gypsum …

Caner Zanbak and Randolph C. Arthur Geochemical and engineering aspects of anhydrite/gypsum phase transitions Bulletin of the Association of Engineering Geologists (November 1986) 23 (4): 419-433

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Review of gypsum reinforced composites as building materials

The utilization of gypsum reinforced composites as building materials has garnered considerable attention owing to their exceptional amalgamation of mechanical strength, fire resistance, and versatile applications. This review initiates by introducing gypsum as a pivotal mineral in construction, subsequently exploring the concept of composite materials and …

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Difference Between Gypsum and Anhydrite

Gypsum vs Anhydrite. Gypsum, also called hydrated calcium sulphate (CaSO4 · 2H2O) and anhydrite (CaSO4), also called hydrous calcium sulphate are the major minerals in the sedimentary rocks of rock gypsum and rock anhydrite respectively. Gypsum consists of calcium, sulfur and water while anhydrite consists of calcium, sulfur and oxygen.

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Grenzebach linked to Rose Gypsum plans in Cuba

Cuba: Rose Gypsum has thanked Grenzebach and GPM Engineering for the company's help in negotiations with Empressa Materiales de Construccion. The companies have been in talks with the state-owned company to build a gypsum wallboard plant for Cuban and the Caribbean market. The plans also include production facilities for ceiling panels.

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(PDF) Anhydrite vs Gypsum: Impact on Cement Quality

In this report, quality parameters gypsum and anhydrite cement samples are also investigated. With respect to learn effects of gypsum and anhydrite on cement parameters, the physical and mechanical parameters of cement samples which is mixture of clinker-gypsum and clinker-anhydrite with 4.0, 4.5, 5.0, 5.5 and 6.0% are investigated. 3.1.

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Geochemical and Engineering Aspects of Anhydrite/Gypsum …

*The material contained in this document is based upon work supported by a National Aeronautics and Space Administration (NASA) grant or cooperative agreement.

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Mechanism and kinetics of gypsum–anhydrite

Theoretically, gypsum is the stable solid phase in water up to 45–50 °C, and above that it transforms into anhydrite (Dutrizac, 2002, Farrah et al., 2004, Freyer and Voigt, 2003; Nývlt, 1997).During sulphuric acid neutralization with calcium-containing bases which occurs below 100 °C, first gypsum forms as a metastable phase because of its higher solubility, according to the …

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Analysis of anhydrite gypsum effects on quality of cement

In this report, quality parameters gypsum and anhydrite cement samples are also investigated. With respect to learn effects of gypsum and anhydrite on cement parameters, the physical and mechanical parameters of cement samples which is mixture of clinker-gypsum and clinker-anhydrite with 4.0, 4.5, 5.0, 5.5 and 6.0% are investigated. 3.1.

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Anhydrite

Anhydrite was first discovered in 1794 in the Hall salt mine near Innsbruck, Austria, and named then or shortly after by Abraham Gottlob Werner. The depth of the occurrence was critical to the discovery, because nearer the surface circulating ground water had altered the anhydrite to gypsum. Massive orange anhydrite from Novoveska Huta, Slovakia.

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Anhydrite gypsum

Unlike anhydrite, natural gypsum contains water. The liquid component ensures that the material is softer, and this also facilitates mining in the quarries. As with other natural materials, gypsum and anhydrite stocks are limited resources, which means that more focus needs to be on alternative materials going forward.

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Influence of Anhydrite on the Properties and Microstructure …

As the anhydrite content increased, the initial and final setting times of the decreased because the anhydrite promoted the hydration of the . The XRD results (see Section 3.2 ) indicated that ettringite (3CaO•Al 2 O 3 •3CaSO 4 •32H 2 O, or AFt for short) had formed due to the reaction of and anhydrite [ 27 ], accelerating the ...

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Minerals | Free Full-Text | Gypsum Crystals Formed by the Anhydrite …

Round 1. Reviewer 1 Report Comments and Suggestions for Authors. The manuscript "Gypsum crystals grown by solution-mediated anhydrite-gypsum phase transition: Application to the formation of the geode of Pulpí" aims to describe the experiment of the nucleation and growth of single gypsum crystals from calcium sulphate solution inside airtight …

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Gypsum plasterboard production plants and …

Gypsum Plasterboard Production Equipment and Plants. Knowledge and technolgy for light gypsum boards. Thanks to our knowledge and expertise gypsum and plasterboard production, we offer to our customers complete …

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Global Gypsum and Anhydrite Industry

II-27 High-Quality Finish and Time Saving Attributes Make Gypsum Plaster/Plaster of Paris the Preferred Choice of Builders II-28 Gypsum in Agriculture Sector: A Primary Source of Nutrients for ...

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Gypsum/anhydrite: Some engineering problems

This paper reviews the problems of constructing on gypsum/anhydrite and their engineering significance and provides short case …

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The Solubilities and Thermodynamic Equilibrium of …

anhydrite into gypsum crystals. This transformation takes place via the solution phase, i.e. via anhydrite dissolution and gypsum precipitation. The chemical dissolution and precipitation reactions of gypsum and anhydrite are CaSO 4 2H 2O $ Ca2þ þ SO2 4 þ 2H 2O ð1Þ and CaSO 4 $ Ca2þ þ SO2 4; ð2Þ respectively.

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Dehydration Pathways of Gypsum and the Rehydration …

where r ij and σ ij are the actual and reference distances between atoms i and j, respectively; ε o is the permittivity of free space (ε o = 8.8543 × 10 –12 C 2 J –1 m –1); ε ij is the potential well-depth; and q i and q j are the value of the charge on atoms i and j.The LJ interactions between unlike atoms are treated with the sixth-order mixing rule. 20 The atom-based summation ...

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Analysis of anhydrite's effects on quality of cement

3R&D Engineer of NORM Cement Plant, Baku, Azerbaijan ... gypsum and anhydrite and have 3650±50 cm2/g fineness. During the grinding process, chemical grinding aid is used.

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4.1.6. Dissolution and Conversions of Gypsum and …

Conversion of gypsum to anhydrite and back to gypsum is common due to the thermodynamic instability of these minerals within the physicochemical range of common geologic environments. The...

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Gypsum/anhydrite: Some engineering problems

The engineering properties of gypsum/anhydrite change as a consequence of groundwater, pressure and heat. Gypsum and anhydrite may experience dissolution in the near-surface zone and along the ...

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Gypsum/anhydrite: some engineering problems

Problems caused by the presence of the gypsum/anhydrite rock and their engineering significance are outlined in this paper. The two basic problems that occur are subsidence due to the …

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Gypsum/anhydrite: some engineering problems | Bulletin of …

This paper reviews the problems of constructing on gypsum/anhydrite and their engineering significance and provides short case histories to illustrate some of the problems …

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Geochemical reactions and pore structure analysis of anhydrite/gypsum …

Pure Anhydrite, Gypsum, and Halite samples were subjected to hydrogen exposure for 90 days at high pressure and temperature. ... Future work can build on the findings of this study and investigate geochemical reactivity beyond the experimental conditions tested in this work. Also, the integration of simulation models can provide further ...

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Gypsum: From the Equilibrium to the Growth …

The gypsum crystals (CaSO4·2H2O) crystallizes in a low symmetry system (monoclinic) and shows a marked layered structure along with a perfect cleavage parallel to the {010} faces. Owing to its widespread occurrence, as a single or twinned crystal, here the gypsum equilibrium (E.S.) and growth shapes (G.S.) have been re-visited. In making the distinction …

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TIPS FOR DRILLING ANHYDRITE / GYPSUM …

Preventing and Curing Anhydrite/Gypsum Contamination. 1 A common method of drilling anhydrite or gypsum formations is to pre-treat the mud with thinners that works effectively in the presence of calcium and sulfates and …

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Gypsum/anhydrite: some engineering problems

The engineering properties of gypsum/anhydrite change as a consequence of groundwater, pressure and heat. Gypsum and anhydrite may experience dissolution in the near-surface zone and along the discontinuities, creating karst terrain to depths related to present and/or past groundwater levels. This paper reviews the problems of constructing on …

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Study on the geological and engineering aspects of …

Hydration of anhydrite (CaSO 4) and dehydration of gypsum (CaSO 4 ·2H 2 O) lead to alternating volume changes, thereby posing serious engineering problems to both soil …

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