آخرین محصولات

Impact of aging on the hydration of tricalcium aluminate (C3A)/gypsum

In the production of concrete from cement powder and water, setting behavior of the slurry is determined by the formation of ettringite (Ca 6 Al 2 (OH) 12 · (SO 4 ) 3 · 26 H 2 O) from tricalcium aluminate (Ca 9 Al 6 O 18, abbreviated C 3 A) and gypsum (CaSO 4 · 2 H 2 O). Due to the high reaction potential of cement and water, premature hydration can occur after unintentional …

Mercury release and fraction transformation during …

aDepartment of Environmental Science & Engineering, North China Electric Power University, Baoding 071000, China bInstitute of Environment and Health, Jianghan University ... The results indicated that mercury could be released from desulfurization gypsum during aging process and the release process could be promoted via ultraviolet irradiation

The aging of gypsum in underground mines

The aging properties of gypsum extracted from two underground mines in France (Livry–Gargan and Grozon) have been highlighted by means of observation performed using scanning electron microscopy ...

Experiments on ageing effect of gypsum rock induced by …

Abstract: To investigate the water-induced ageing effect on gypsum rock, different water environment conditions were simulated in the laboratory, including different air humidity conditions and saturated groundwater conditions which may exist in the gypsum mines. Mechanical parameters of gypsum rock specimens were obtained under the pre-set conditions for …

Thermoluminescence dating of gypsum in loess deposits

The radioactive element content within our gypsum samples was orders of magnitude lower compared to the external radiation from the surrounding loess sediments (Table 1).It is obvious that the internal content of radioelements (U, Th, and K) within gypsum was only 0.3–1.0 %, 0.4–1.3%, and 0.4–0.9%, respectively, in comparison to the external radioactive …

Influence of α-Calcium Sulfate Hemihydrate on Setting, …

1. Introduction. Gypsum is a material in which the amount of water of crystallization varies with its surrounding conditions, such as temperature or humidity, and can be classified into three groups, namely, calcium sulfate anhydrite (CaSO 4), calcium sulfate hemihydrate (CaSO 4 ∙1/2H 2 O), and calcium sulfate dihydrate (CaSO 4 ∙2H 2 O) [].Calcium sulfate hemihydrate …

US1713879A

The quantity of water, in either form, necessary to complete- 1 r age the calcined gypsum, will depend on the temperature to w ich the gypsum prodnot was calcined. The higher the degree of calcination, the less is the amount of combined water remaining in the calcined gyp: sum, and therefore, more will have to be added in order to completely ...

(PDF) Influence of selected micro additives content on …

The presented work focuses on the influence of the micromaterials (microspheres, aerogel and polymer hydroxyethyl methyl cellulose) on thermal properties of gypsum.

Soil stabilization with gypsum: A review

Gypsum can significantly enhance the UCS and CBR of soils, particularly high-plasticity and expansive clays. The increase in strength is primarily attributed to the cation exchange capacity and formation of cementitious hydration products.

Mercury release and fraction transformation during …

DOI: 10.1016/J.FUEL.2017.12.120 Corpus ID: 102685130; Mercury release and fraction transformation during desulfurization gypsum aging process (UV irradiation) @article{Diao2018MercuryRA, title={Mercury release and fraction transformation during desulfurization gypsum aging process (UV irradiation)}, author={Xingzhong Diao and Chun …

Experimental study on hardening characteristics and loading rate

Gypsum based non-conventional composites have also been studied for numerous practical applications. For instance, the experimental study on gypsum-quicklime-soil grout suggests that this type of gypsum based composite can effectively be used to repair earthen site cracks, and the performance of this grout was found to be superior to traditional …

Insights into stable strontium isotope fractionation in marine gypsum …

The age of the gypsum sample is 1600–1650 years B.P. (Rouwendaal, 2017), ... Ca/Sr ratios of both marine aragonite and the fluid inclusions are distinctly lower than those of the gypsum, and the experimental gypsum samples broadly fit the trajectory of such mixing. However, to explain the composition of the samples, one would have to assume ...

Homebrew Experiment: Adding Gypsum To Beer To Affect …

So how did my experiment go? Did adding gypsum to beer affect its flavor? Initially, the concentration of gypsum I was adding to the beer was too low to make any difference. I started with a 1 gram gypsum/500 mL water solution. Adding 1 mL of said solution to a 125 mL sample of beer only increased the effective concentration of by 1.6 ppm ...

Mercury release and fraction transformation during …

National Natural Science Foundation of China; Foundation of State Key Laboratory of Coal Combustion; Fundamental Research Funds for the Central Universities

Artificial aging of gypsum binder in terms of thermodynamics

Artificial aging of gypsum binder in terms of thermodynamics, S A Nekrasova, D D Khamidulina

the role of gypsum aging

US2177668A Process of aging calcined gypsum Google. WebThe process of aging calcined gypsum including reacting the gypsum, while confined, and in agitation, under a predetermined controlled temperature condition, for a definite time period, with a gas having a relative humidity sufficient to rehydrate the gypsum to the hemihydrate but ...

Gypsum hydration: a theoretical and experimental study

The present paper addresses the gypsum hydration study with the theoretical and experimental method. The microstructure of gypsum changes during the hydration

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

Meanwhile, the peaks represent gypsum has decreased trend with curing age and concentration of NaAlO 2. And the gypsum related peaks have lower intensity at each curing age compared to Ref. ... The above experimental results indicates that the addition of NaAlO 2 in PG-slag binder system can increase the hydration degree of GGBS, accelerate the ...

Ancient architectural pathology of blue bricks and brick …

Aging tests were conducted on blue brick carvings and brick cubes based on the White Temple Tower in Lanzhou City, China. Parameters such as mass, ultrasonic velocity, …

Preparation of α-High Strength Gypsum from Flue Gas …

Flue Gas Desulfurization Gypsum Pretreated by Hydrothermal-aging Method SU Yixin1, GAO Lili1,2, CHEN Xueqing 1*, LI Zhishui3, LI Yun, CAO Jilin1 ... Funded by National Natural Science Foundation of China (No.22008049), Natural Science Foundation of Hebei Province, China (Nos.B2020202081 and B2018202330), Key Laboratory of ...

Implementation of the Mathematical Planning of an Experiment …

The article carried out the mathematical planning of an experiment on the selection of the optimal composition of a new building finishing material based on a gypsum binder filled with wood filings.

Preparation of α-High Strength Gypsum from Flue Gas …

2 Experimental 2.1Materials FGD gypsum was produced for FGD system at a plant in Tianjin, China. Sodium chloride (NaCl), ... 3.1 synthesized crystals are completely transformed to Pretreatment of FGD gypsum The hydrothermal-aging method was employed to pretreat the washed FGD gypsum. As shown in Fig.2(a), the washed FGD gypsum was ...

Enhancing Pb2+ removal efficiency in flow-through systems …

FGD gypsum is a byproduct of the sulfur-containing fuel combustion industry, and China produces approximately 6.5 million tons of FGD gypsum annually [18].The storage of FGD gypsum not only consumes a substantial amount of land resources but also poses potential environmental hazards [19].FGD gypsum has a chemical composition and properties similar …

The aging of gypsum in underground mines

The aging properties of gypsum extracted from two underground mines in France (Livry-Gargan and Grozon) have been highlighted by means of observation performed using scanning electron microscopy on samples taken along horizontal boreholes drilled through to the middle of several pillars. The aging process is exhibited by the presence of traces of dissolution (edges of the …

Impact of accelerated climatic aging on the behavior of …

Freezing-thawing and wetting-drying accelerated aging tests are considered to simulate outdoor conditions. Two straw-gypsum plaster composites were designed. Long-term …

PRODUCTION OF PLASTER FROM GYPSUM DEPOSITS IN …

In this work, the improvement of the setting time (S.T.) of the Plaster of Paris produced from gypsum deposits of Jabal Mulaih, in Tafila, south Jordan, was investigated. The setting time …

Phase evolution and mechanical performance of red mud-gypsum …

Dihydrate gypsum facilitates the formation of AFt crystal and C(N)-A-S-H gels by causing the dissociation and repolymerization of aluminosilicates in the entire system. The accumulation of curing age results in a sharper AFt crystal peak, a larger dispersion peak, and a smaller gypsum peak.

Experimental study on the catalytic action of heavy metals …

Black crusts are complex layers that form on stone surfaces due to the deposition and reaction of SO 2 and PM with the carbonate substrate. These layers are typically stratified, with the outer ones being rich in gypsum, carbonaceous particles, and other species, while the inner layers usually contain unreacted calcite and other components from the undamaged stone.

(PDF) Improvement of Local Gypsum Plaster …

Abstract:- An investigational study had been done in this research to improve the setting time of Local Gypsum Plaster by using two additives, namely : Tree Glue Powder (TGP) and Polyvinyl...

Investigation of mechanical properties of phosphorus building gypsum …

After the aging process, the product displays enhanced uniformity. The phosphorus construction gypsum powder now ready for use in the experiment is sifted through a 0.2 mm square-hole sieve, resulting in a sieve residue of 1.2 %, meeting the fineness requirement for construction gypsum as stipulated in "Construction Gypsum" GB/T9776-2008. 2.3.

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