Even though a lot of research has been carried out concerning the preparation of carbonate apatite (CHA), they were related to CHA in the form of powder. In the present study, macroporous CHA bone substitutes were prepared through composition-transformation of gypsum and Ca-hydroxide. Here, we investigated the effect of added Ca-hydroxide to gypsum, carbonation periods, and hydrothermal tempera...

Time-resolved energy dispersive X-ray diffraction (EDXRD) data have been measured in situ from cast blocks of gypsum, CaSO(4) x 2 H(2)O, in the presence of reactive phosphate solutions under hydrothermal conditions (100 < or = T < or = 180 degrees C) in order to understand the formation of hydroxyapatite monoliths, for applications such as in artificial bone or dental materials. Measurement of ...

In-situ atomic force microscopy (AFM) experiments were performed to study the overall process of dissolution of common carbonate minerals (calcite and dolomite) and precipitation of gypsum in Na2SO4 and CaSO4 solutions with pH values ranging from 2 to 6 at room temperature (23 ± 1 °C). The dissolution of the carbonate minerals took place at the (104) cleavage surfaces in sulfate-rich solutions ...

[1] Soil sulfates are present in arid and hyperarid environments on Earth and have been found to be abundant in soils on Mars. Examination of soil gypsum from the Atacama Desert, Chile, the Mojave Desert, United States, and Al-Jafr Basin, Jordan, revealed endolithic cyanobacteria communities just below the surface of soil gypsum samples. Optical and scanning electron microscope observations of ...

Gypsum is the dihydrate form of calcium sulfate. The word "gypsum," however, is used to describe different phases of the same material, including anhydrite (calcium sulfate, with no water of crystallization), selenite, calcined gypsum, and plaster of Paris. It forms as evaporites from marine waters and is usually found collectively with other mineral deposits such as quartz, sulfur, and clays. ...

Based on the engineering background of water dissolving mining for hydrocarbon storage in multi-laminated salt stratum, the mixed mode fracture toughness and fracture trajectory of gypsum interlayers soaked in half-saturated brine at various temperatures (20°C, 50°C and 80°C) were studied by using CSNBD (centrally straight-notched Brazilian disc) specimens with required inclination angles (0°, ...

the study area is a part of the sanandaj-sirjan metamorphic belt comprising low- to high-graderegional and contact metamorphic rocks that are intruded by various plutonic bodies. garnet crystals areabundant in pelitic schists, amphibole schists, migmatites, hornfelses and aplites. they are mostly almandinerich(xalm>60) pyralspite garnets and show dodecahedron, trapezohedron and mixed (dodecahed...

A 3-D (3-dimensional) numerical modeling approach to analyze the coupling of mineral scale, concentration polarization and permeate flux was developed and demonstrated for a gypsum membrane scaling test in a plate-and-frame RO membrane module geometry. The impact of concentration polarization on mineral gypsum scaling, and in turn the impact of mineral scale on the concentration polarization fi...

The isotopic composition and mass balances of sources and sinks of sulfur are used to constrain the limnological–hydrological evolution of the last glacial Lake Lisan (70–14 ka BP) and the Holocene Dead Sea. Lake Lisan deposited large amounts of primary gypsum during discrete episodes of lake level decline. This gypsum, which appears in massive or laminated forms, displays dS values in the rang...