This study discusses strength deterioration during the curing process of fly ash geopolymer and the use of CaSO4·2H2O (gypsum) as a deterioration remedy when the ash was synthesized using a 10M NaOH and Na-silicate solution. The strength decline was mainly due to the widespread formation of nanometer-sized cracks that were related to excessive Na and Si concentrations at an early age. Use of 2 ...

A lack of well preserved paleoclimate indicators coupled with the abundance of gypsic soils in arid and semi-arid regions has stimulated research on using dO and dD isotopic analysis of the hydration water of gypsum to interpret paleoclimate. This study stresses the importance of establishing a pedogenic origin for gypsum crystals prior to isotopic analysis and evaluates the dominant processes ...

The filling mining method is important in realizing the green of mineral resources. Aiming at problems land resource occupation, environmental pollution, and rational utilization coal-based solid wastes such as coal gangue, fly ash, desulfurization gypsum, a new paste material was developed with gypsum raw materials. microstructure materials analyzed by XRD SEM. Combined Box-Behnken experimenta...

Flue gas desulfurization gypsum (FGD) is a waste material arouse from coal power plants. Hydroxyapatite (HAP) is a biomaterial with porous structure. In this study, FGD gypsum which retrieved from coal power plant in Turkey was characterized and HAP particles which can be used as an adsorbent in wastewater treatment application were synthesized from the FGD gypsum. The raw materials are charact...

Winemaking of musts acidified with up to 3g/L of gypsum (CaSO4 2H2O) and tartaric acid, both individually and in combination, as well as a chemical modeling have been carried out to study the behaviour of these compounds as acidifiers. Prior to fermentation gypsum and tartaric acid reduce the pH by 0.12 and 0.17 pH units/g/L, respectively, but while gypsum does not increase the total acidity an...

We report the δ34S and δO(SO4) measured in gypsum, pyrite, and elemental sulfur through a 456-m thick sediment core from the center of the Dead Sea, representing the last ∼200 kyrs, as well as from the exposed glacial outcrops of the Masada M1 section located on the margins of the modern Dead Sea. The results are used to explore and quantify the evolution of sulfur microbial metabolism in the D...

Depending on the desulfurization reaction temperature, it can be divided into fly ash generated at hightemperature furnace zone and at low-temperature flue gas zone. For simulating those two kinds of desulfurization ash, the ordinary fly ash mixed with different weight percentage of CaSO4·2H2O is divided into 2 groups, the first group is followed by calcining at 900°C, another drying at 100°C. ...

Fibrous dusts (chrysotile, glass fibers, nemalite, palygorscite, and gypsum) and granular dusts (actinolite, biotite, hematite, pectolite, sanidine, and talcum) were injected intraperitoneally into rats. The fibrous dusts (other than gypsum) resulted in a high incidence of mesothelioma (30 - 67%). Gypsum produced only 5% and granular dusts none at all. It is suggested that the fibrous shape lea...