العثور على الحق
We هي شركة ذات تقنية عالية تدمج البحث والتطوير والإنتاج والتوزيع ، وتوفر كسارة ، وصنع الرمال ، ومعدات طحن ، ومحطة تكسير متنقلة ، إلخ.
We هي شركة ذات تقنية عالية تدمج البحث والتطوير والإنتاج والتوزيع ، وتوفر كسارة ، وصنع الرمال ، ومعدات طحن ، ومحطة تكسير متنقلة ، إلخ.
20201210 Dihydrate gypsum Compressive strength Phase conversion 1. Introduction In contrast to Portland cement (PC), calcium aluminate cement (CAC) generally exhibits rapid strength development and resistance to sulphates [1], acid [2], and fire [3].احصل على السعر
2019123 consumption of hemihydrate and formation of dihydrate. 1. Ultrasonic results indicate gypsum hydration reaction consists of two stages: the dissolution of hemihydrate in the first stage and the nucleation and precipitation of dihydrate in the second stage. 2. Gypsum hydration is strongly influenced by water amount. Spread flow test isاحصل على السعر
The apparent empirical activation energies (Ea) suggest that the transition from gypsum to hemihydrate is mainly controlled by nucleation and growth mechanism, while the transition from gypsum to γ-anhydrite is mostly followed by phase boundary mechanism.احصل على السعر
20211213 Gypsum has five phases, namely dihydrate gypsum (CaSO 4 2H 2O), hemihydrate gypsum (CaSO4 0.5H 2 O), III-anhydrite (CaSO 4 ), II-anhydrite (CaSO 4) and I-anhydrite (CaSO 4 ). Among these, hemihydrate gypsum احصل على السعر
200221 There is a considerable research interest in the study of structure and coordination behaviour of water molecules in gypsum (calcium sulphate dihydrate, CaSO 4 2H 2 O) and hemihydrate (plaster of Paris, CaSO 4 1/2H 2 O).احصل على السعر
201811 The hydration of calcium sulphate hemihydrate (CaSO40.5H2O) leading to the crystallization of gypsum (calcium sulphate dihydrate CaSO42H2O) has been the subject of several investigationsاحصل على السعر
2021524 The gypsum-hemihydrate transformation has been long studied as a laboratory analogue for seismogenic dehydration reactions during subduction 8, 9 and as a model of metamorphic dehydrationاحصل على السعر
2007121 The structures were identified as crystals formed during the dehydration process of gypsum inside of a gypsum crystal. The hypothesis of Fowler et al. [13] remarked that α-HH is formed as...احصل على السعر
2019426 It was also found that gypsum is stable in the low-temperature and high water vapor pressure region and does not dehydrate to form any calcium sulfate hemihydrate. Finally, the rehydration mechanism of soluble anhydrite was studied by احصل على السعر
2021825 This refers to the mechanism of crystallization of calcium sulfate dihydrate from solutions: high-density liquid precursors -> hemihydrate nuclei -> amorphous gypsum -> crystalline gypsum [40]. The hardening process is divided into three periods: 1) the formation of a solution saturated with respect to hydration products; 2) setting, when theاحصل على السعر
200221 The bonding nature of water in gypsum, CaSO 4 2H 2 O, and hemihydrate, CaSO 4 1/2H 2 O, was suggested by characteristic absorption bands of water and sulphate ions. The infrared spectral data indicate the presence of anion water in gypsum and hemihydrate through hydrogen bonding. Negative shifting of bending vibration of SO 4 احصل على السعر
2021721 α-Calcium sulfate hemihydrate (α-HH) is an important cementitious material, which can be prepared by hydrothermal method from calcium sulfate dihydrate (DH) in an electrolyte solution. Study of the conversion kinetics of DH to α-HH in NaCl solution is helpful for understanding the control process. In this , X-ray diffraction احصل على السعر
20211213 Dihydrate gypsum is the dominant phase composition in PG, it is a stable phase at room temperature but can be converted into α-hemihydrate gypsum (α-CaSO 4 0.5H 2 O) [16] and β-hemihydrate gypsum (β-CaSO 4 0.5H 2 O), also called building gypsum [17] according to different heating methods. α-hemihydrate gypsum is prepared احصل على السعر
200731 The hydration of calcium sulphate hemihydrate (CaSO 4 0.5H 2 O) leading to the crystallization of gypsum (calcium sulphate dihydrate CaSO 4 2H 2 O) has been the subject of several investigations over a long period and a vast amount of data is widely distributed throughout in the literature. In this review article an overall picture of the احصل على السعر
200731 The hydration of calcium sulphate hemihydrate (CaSO 4 0.5H 2 O) leading to the crystallization of gypsum (calcium sulphate dihydrate CaSO 4 2H 2 O) has been the subject of several investigations over a long period and a vast amount of data is widely distributed throughout in the literature. In this review article an overall picture of the احصل على السعر
2006122 The deterioration of buildings and monuments by gypsum is the result of crystallization cycles of this salt. Although gypsum can dehydrate to a hemihydrate, the mineral bassanite, and to an anhydrate, the mineral anhydrite, this reaction occurs in nature on a geological time scale and therefore it is unlikely to occur when gypsum is found on احصل على السعر
2019430 where P H 2 O(gypsum − hemihydrate) is the equilibrium water vapor pressure of the reaction for the transformation of CaSO 4 2H 2 O into β -CaSO 4 0.5H 2 O, P H 2 O(gypsum − anhydrateاحصل على السعر
In more detail, hemihydrate was added to water to perform the hydration reaction to obtain dihydrate, and then, the formed dihydrate was crushed and calcinated back to beta hemihydrate. The stoichiometric amount of water needed for hydration is around 15.7 ml per 100 g, but an excess amount of water is required to obtain gypsum slurry with goodاحصل على السعر
200221 The bonding nature of water in gypsum, CaSO 4 2H 2O, and hemihydrate, CaSO4 1/2H 2O, was suggested by characteristic absorption bands of water and sulphate ions. The infrared spectral data indicate the presence of anion water in gypsum and hemihydrate through hydrogen bonding. Negative shifting of bending vibration of SO4 ion احصل على السعر
2019210 The hemihydrate gypsum used in this study was collected from Baotian New Building Materials Co.,Ltd. The particle size of the hemihydrate gypsum is ASTM 200 mesh and the chemical composition of hemihydrate gypsum is listed in Table 1. The black tea powder came from Fujian tea Co.,Ltd. The particle size of the black tea powder is احصل على السعر
20221016 Calcium sulfate exists in three forms, namely dihydrate or gypsum (CaSO42H2O), anhydrite (CaSO4), and hemihydrate or bassanite (CaSO40.5H2O) depending on temperature, pressure, pH, and formation conditions. The formation of calcium sulfates occurs widely in nature and in many engineering settings. Herein, a dataset احصل على السعر
20201123 Chemical adsorption was formed between O of KAP, Ca²⁺ and O of dihydrate gypsum (0 2 0) surface (OKAP- Ca²⁺-Osurf) in the presence of Ca²⁺, thus KAP can be stably adsorbed on theاحصل على السعر
2014422 Gypsum wallboard (GWB) mainly consists of gypsum, a naturally occurring material. It is a soft sulfate mineral, having a crystalline form of calcium sulfate combined with water known as calcium sulfate dihydrate, CaSO 4 2H 2 O. The hemihydrate, CaSO 4 0.5H 2 O has two crystalline forms: α and β where as anhydrite consists of γ and βاحصل على السعر
2023101 Herein, hemihydrate gypsum (HHG) whisker, an inorganic material with excellent performance, prepared using LAG as the raw material via atmospheric pressure salt solution method was investigated. Nitrate enhanced the salt effect of the solution, which increased the solubility of dihydrate gypsum (DDG), and further accelerated the احصل على السعر
In the method for drying dihydrate gypsum powder containing surplus water according to the present invention (hereinafter simply referred to as the drying method of the present invention), dihydrate gypsum powder and hemihydrate gypsum powder (CaSO 4 1 / 2H containing surplus water). 2 O powder). When both are brought into contact, according toاحصل على السعر
2021111 The main synthetic materials are α-hemihydrate gypsum dihydrate, calcium carbonate, adsorption materials and composite material (Table 4). The preparation of α-hemihydrate gypsum (α-HH) is an effective way to realize the high-value utilization of FGD gypsum. The formation mechanism and crystal structure of α-HH are shown in Fig. 4. احصل على السعر
202259 The morphology of hemihydrate gypsum prepared from dihydrate gypsum contained 15 wt% (a) and 0 (b) of attachment water. 3.4. FTIR Results of α-HH with Different Modifier Dosages . FTIR spectroscopy is one important method to study the interaction mechanism between chemicals and the material surfaces [18,30,31,32]. The احصل على السعر
2023322 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, based احصل على السعر
2023131 Preparation of α-hemihydrate gypsum crystal is an approach for utilization of phosphogypsum (PG), but the soluble phosphorus impurities in PG have a crucial influence on the performance of α-hemihydrate gypsum. In this article, different forms of soluble phosphorus (H3PO4, H2PO4− and HPO42−) on the setting time and mechanical احصل على السعر
