the use of recycled bassanite, produced from gypsum wastes, in ground improvement projects is initiated recently in japan to eliminate the huge quantities of gypsum wastes. meanwhile the use of recycled bassanite has a positive effect on the environment and economy, it has many challenges. these challenges are related to the release of fluorine more than the standard limits results in contamina...

Calcium sulfate is an important construction material. More than 1600 million square meters of interior surfaces are covered with plasterboards in Europe each year. Plasterboard manufactured by transforming mined or recycled gypsum (CaSO4 × 2 H2O) to bassanite ½H2O) a time- and energy-consuming heating process. A fast sustainable way produce solvent-assisted milling, thereby eliminating the nee...

Structure analysis using single-crystal diffraction was carried out as a contribution to the dispute about the nature of the water channel structure of bassanite (CaSO(4)·0.5H(2)O). A recent result of Weiss & Bräu (2009) for the crystal structure of bassanite (monoclinic, space group C2) at ambient conditions of air humidity was confirmed. In the presence of high relative air humidity the cryst...

Citric acid added as set retarder significantly contributed to enhancing the setting temperature and to extending the thickening time of a calcium aluminate phosphate (CaP) geothermal cement slurry consisting of calcium aluminate cement (CAC) as the base reactant and sodium polyphosphate (NaP) solution as the acid reactant. The set-retarding activity of citric acid was due to the uptake of Ca2'...

A synthetic Topopah Spring Tuff water representative of one type of pore water at Yucca Mountain, NV was evaporated at 95 °C in a series of experiments to determine the geochemical controls for brines that may form on, and possibly impact upon the long-term integrity of waste containers and drip shields at the designated high-level, nuclear-waste repository. Solution chemistry, condensed vapor ...

A new experimental determination of the stability relationships for the dehydration of gypsum to the hemihydrate mineral bassanite at elevated temperature and pressure is described. The experimental method used depends on the observation of very small changes in pressure on the onset of reaction due to the potential volume change in the reaction. The technique yields P T data of very high preci...

Introduction: The secondary minerals of Martian meteorites have long fascinated the scientific community due to their possible formation on Mars, which in turn can provide insight into weathering processes on Mars. Minerals such as jarosite have a restricted set of formation conditions and can provide information as to the pH, Eh, latitude and temperature of fluids on Earth [1-4]. Ca-sulfate (g...