Process Development – GypTechno Solution

Gypsum rock is converted into gypsum plaster by driving off some of the chemically combined water. Heating gypsum at 154°C with results in a hemi-hydrate (CaSO4. 1⁄2H2O) – with three quarters of the water removed. Gypsum hemi-hydrate is …

The Influences of Soluble Phosphorus on …

Phospho-gypsum is an industrial solid waste discharged from the phosphate production process. The waste includes complex impurities such as phosphoric acid and its salts, fluoride, and organics. Usually, …

Experimental Study on Physical and Mechanical Properties of Gypsum …

The hydration process of gypsum rock was accelerated due to the weak sedimentary surface and the swelling and cracking of filling minerals, but the macroscopic damage of the sample was also accelerated. In the process of water absorption, anhydrite crystal and water molecules were broken and recombined, filling the micro-pores formed …

Effect of phosphate rock acid insoluble residue on hydration process

The application of α-hemihydrate gypsum (α-HH) is limited by several factors, such as a rapid hydration rate, short setting time, poor water resistance, and high cost. Especially because of the high production cost, although α-HH has excellent mechanical strength, it is rarely used in the field of building materials. In this study, …

Gypsum hydration: A theoretical and experimental …

Hardening of mineral binders (cement, gypsum, lime, clay) is accompanied by the dissolution of minerals from the binder surface, …

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 …

The Simulation and Analysis of Dehydration Process of FGD Gypsum …

The Simulation and Analysis of Dehydration Process of FGD Gypsum Grouted Wall: ZENG Ziyue 1,2, YANG Jiansen 1, WEI Yongqi 2: 1 School of Civil and Hydraulic Engineering, Ningxia University, Yinchuan 750021, Ningxia, China 2 School of Material Science and Engineering, Tongji University, Shanghai 201804, China

Hydration and mechanical properties of FGD gypsum

1. Introduction. Flue gas desulfurization (FGD) gypsum is an industrial by-products, which primarily consists of dihydrate gypsum (CaSO 4 ⋅2H 2 O),and the treatment of 1 t of SO 2 in coal flue gas by limestone-gypsum wet desulfurization technology will produce about 2.7 t of FGD gypsum, and China emitted nearly 100 …

INFLUENCE OF MACROMOLECULE-TYPE RETARDERS ON THE HYDRATION PROCESS …

The effect of macromolecule-type retarder bone glue on the hydration process,ion concentration in liquid phase and supersaturation degree,and crystal morphology of dehydrate of building gypsum was investigated.Furthermore,by using the X-ray photoelectron spectroscopy technique,its retarding mechanism was also studied.The …

Effects of different gypsum varieties on the hydration and …

The effects of anhydrite and desulfurization gypsum (DSG) on the hydration and mechanical properties of cement were evaluated. Results show that RM-based FSAC can be calcined at 1300 °C, and the hydration process is closely related to the varieties and quantities of the calcium sulfate set regulator.

The Mechanochemical Process and H2SO4 Treatment on the …

Flue gas desulfurization (fgd) is a waste incineration process that employs limestone slurry (CaCO 3) as a scrubber to remove SO 2 from exhaust gases, thereby reducing pollutant emissions. CaCO 3 reacted with SO 2 to form calcium sulphite (CaSO 3), which was then oxidized to form anhydrite (CaSO 4) and gypsum (CaSO 4 ⋅2H 2 O), …

Structural evolution during the dehydration of gypsum …

The dehydration process of gypsum under high pressure. Physics and Chemistry of Minerals, Vol. 39, Issue. 1, p. 65. ... Pressure-induced structural phase transition and dehydration for gypsum investigated by Raman spectroscopy and electrical conductivity. Chemical Physics Letters, Vol. 706, Issue., p. 151.

The Influences of Soluble Phosphorus on Hydration Process …

During the hydration process, SO 4 2− can be replaced by HPO 4 2− into gypsum crystals to form a solid solution, which further affects the gypsum performance . In addition, the crystal morphology of CaSO 4 ·2H 2 O is modified by the impurities in phospho-gypsum, and needle-like gypsum crystals have a higher compressive …

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 …

Formation of α-Hemihydrate Inside of a Gypsum Crystal …

Therefore, the dehydration process of gypsum and the rehydration of hemihydrate were investigated. This dehydration process is technically performed in three different ways. Heating up, i.e., in a ...

Effect of Industrial Byproduct Gypsum on the Mechanical …

The hydration process produces less monosulfoaluminate hydrate, which can form delayed ettringite with gypsum, because of the lower amount of 3CaO·Al 2 O 3 (from OPC). Moreover, C-S-H and ettringite encapsulating gypsum particles can reduce the solubility of gypsum in water, enhancing the matrix's water resistance.

Experimental Study on Physical and Mechanical Properties of …

Role of Gypsum in Cement and its Effects – …

Role of Gypsum in Cement The main purpose of adding gypsum in the cement is to slow down the hydration process of cement once it is mixed with water. The process involved in hydration of cement is that, when …

Gypsum: Properties, Uses, Formation, Types – Geology In

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, saline lakes, or near geothermal springs.When a body of water rich in dissolved calcium (Ca²⁺) and sulfate (SO₄²⁻) ions undergoes …

From atom level to macroscopic scale: Structural mechanism of gypsum

Introduction. 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 O) or γ-anhydrite …

Effect of Mineral Admixtures on Physical, Mechanical, and

The hydration processes for these samples were categorized into two stages. In the first stage, the hydration exothermic peak emerged at 0–1 h, corresponding to the hydration process of hemihydrate gypsum. The addition of mineral admixtures slightly reduced the intensity of the exothermic peaks by delaying the contact between …

Effect of Gypsum on Hydration and Hardening Properties of …

The effects of different dosages of gypsum on the hydration and hardening properties of AMCSA, such as setting time, hydration rate, compressive strength and hydration products, were studied. The results show that the mineral content of ye'elimite, C 2 S, C 3 S and iron phase in the calcined AMCSA clinker are 48.5 wt.%, 32.6 wt.%, 11.7 …

Dissolution and conversions of gypsum and anhydrite

Calcium sulfate occurs in nature mainly in form of three different minerals distinguished by their degree of hydration: gypsum (CaSO 4 ), bassanite (CaSO 4 ⋅0.5H 2 O) and anhydrite (CaSO 4 ...

Improving the early-age properties of eco-binder with high …

Gypsum in PG is an important raw material in building materials, hence, the recycling of PG into building materials is a more prospective direction regarding resource saving and cutting down CO 2 emission. ... and the hydration process, quantity and quality of the hydration products, slag hydration degree, microstructure and morphology, etc ...

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

Understanding gypsum in 3 diagrams

The third illustrates the hydration energy of hemihydrate as it reacts with water. Diagram 1 - Dehydration. The first process is the formation of hemihydrate or anhydrite from dihydrate. To obtain more information about this step, gypsum crystals were grown from sodium sulphate and calcium chloride via a diffusion process.

A Study on the Mechanical Properties and Hydration Process …

Paste backfill prepared with ultrafine tailings often faces difficulties in meeting engineering requirements. To address the challenge of using ultrafine tailings, this work utilized a slag cemented ultrafine tailings paste backfill (SCUPB) composed of slag, Portland cement, and desulfurized gypsum as the cementitious materials, with a …

Effects of Fluorogypsum and Flue-Gas Desulfurization Gypsum …

Waste gypsum has low hydration activity, especially fluorogypsum with anhydrite as the main composition. Its hydration reaction is slow at early age and requires a long hydration time. The activation of waste gypsum and the hydration reaction process in cement-based materials and the formation mechanism of the microstructure …

Improving the early-age properties of eco-binder with high …

Hydration process and kinetics of PG-slag pastes with and without NaAlO 2. ... The peak at 120∼160 °C (peak 2) mainly corresponds to the dehydration of gypsum and can reflect the gypsum consumption during hydration in PG-slag binder system [33, 53]. Download: Download high-res image (641KB)

From atom level to macroscopic scale: Structural mechanism …

First study of gypsum single crystal dehydration using X-ray absorption tomography. Evidence and mechanism of a multi-scale crack pattern due to structure …

The Future of Gypsum

Water required in gypsum based cement for the hydration process is less. The use of gypsum as an additive in cement ranges from 2.5 to 5 per cent. In its natural form, gypsum can be found as thick layers in shale and as attractive crystals. ... Turkey, Russia, UAE, Oman and Chile are the leading producers. India has deposits mainly in …

Gypsum Manufacturer & Supplier Oman|Marble, Limestone …

Established in 2010, GLOBAL GYPSUM BOARD CO LLC is the first to operate gypsum board and value added plaster plants in the Sultanate of Oman, with production capacities of 15 Million sqm for 12.5mm thicknesss plasterboards, 60,000 MT/year of value added plaster and 150,000 MT/year stucco production capacity.

The role of gypsum in cement

Shreesh Khadilkar reviews the present situation of gypsum, and takes us through a variety of gypsum products, its merits and demerits. Gypsum (CaSO4.2H2O) is used widely in various industries either as gypsum, i.e., the gypsum di-hydrate crystalline variety or as the gypsum hemi hydrates, also known as plaster of Paris (POP) or …

Effects of Steel Slag on the Hydration Process of Solid …

Aiming to enhance the comprehensive utilization of steel slag (SS), a solid waste-based binder consisting of SS, granulated blast furnace slag (BFS), and desulfurization gypsum (DG) was designed and prepared. This study investigated the reaction kinetics, phase assemblages, and microstructures of the prepared solid waste …

Microstructure and mechanical properties of β …

The hydration process of the β-hemihydrate was investigated applying an ultrasonic wave method and the influence of the water content on hydration was analyzed. ... But this finding is in contrast to Solberg and Hansen [9] who reported that hydration of the gypsum is almost independent of water amount within the w 0 /h 0 range of 0.5–1.5.

Experimental Study on the Properties and Hydration …

According to the hydration products and micro-morphological analysis in Section 3.5 and Section 3.6, the hydration reaction process of gypsum-based …