China
Africa
Explore chapters and articles related to this topic
Characterization of factors determining the durability of brick masonry
Published in Jan Kubica, Arkadiusz Kwiecień, Łukasz Bednarz, Brick and Block Masonry - From Historical to Sustainable Masonry, 2020
Determining the type of salt present in the wall is an important element of wall diagnostics as it makes it possible to determine the sources of moisture in the construction object and significantly facilitates this process. Chlorides usually take the form of halite, sylvin, salmiac and bischofite, nitrates in the form of nitronatrite, nitrocalcite, nitrommagnezite, sulphates in the form of mirabilite, acarnite, epsomite, kizerite, tenardite and gypsum, whereas carbonates often take the form of micrite, thermonatrite and natron (Szostak & Trochonowicz 2015). Depending on the structure or degree of hydration, crystals can take various mineralogical forms, e.g. calcium carbonate take the form of calcite, aragonite or micrite.
Removal of Inorganic Contaminants
Published in Samuel D. Faust, Osman M. Aly, Chemistry of Water Treatment, 2018
Sulfate occurs mainly in such evaporite sediments as gypsum (CaSO4·2H2O), anhydrite (CaSO4), epsomite (MgSO4·7H2O), and mirabilite (Na2SO4·10H2O). An extremely significant source of sulfate is the chemical weathering of pyrite (FeS2), which yields S22− anions to the water phase. In turn, these reduced sulfur anions are oxidized catalytically in microbiological systems to sulfate. Since hydrogen ions are produced in the course of this oxidation, waters with acidic pH values result.
Sedimentary Petrology
Published in Supriya Sengupta, Introduction to Sedimentology, 2017
Evaporites are precipitated from solution and concentrated by evaporation. Sodium chloride (halite), and calcium sulphates (gypsum and anhydrite) are common examples of evaporites. Potassium chloride (sylvite), hydrated magnesium chlorides (bischovite and epsomite) are relatively rare varieties of evaporite. All these rock-forming salts are deposited by the process of evaporation of sea-water. The sequence of deposition followed by the common rock-forming evaporites is as follows (beginning with the least soluble mineral, which is always the first to be deposited): gypsum or anhydrite, sylvite and halite.
Desert Rose Stone Constructions Covered with Domes in the Souf Region (Algeria)
Published in International Journal of Architectural Heritage, 2022
Cheima Azil, Boualem Djebri, Fabio Fratini, Giulia Misseri, Luisa Rovero
The mineralogical analysis through X-ray diffraction shows that Tafza (TS) — the stone employed to produce the binder powder for mortars — is made mainly of gypsum and secondarily by quartz, epsomite (MgSO4 ∙ 7H2O), calcite, bassanite (CaSO4 • 0.5 H2O) and anhydrite (CaSO4). As for the Desert Rose stone (DR3), the mineralogical analysis has been selective taking care to separate the bedding mortar. The results show that it is made of gypsum, quartz, and impurities of epsomite (MgSO4 • 7H2O) and calcite. The mineralogical analysis of the mortar (MP) shows that it is made mainly of gypsum and secondarily by dolomite, epsomite (MgSO4 • 7H2O), calcite, bassanite (CaSO4 • 0.5 H2O), anhydrite (CaSO4) and polyhalite [K2Ca2Mg (SO4)4 ∙ 12H2O]. As the information of geology on the study area has already highlighted, the results of the mineralogical analysis show that building materials, blocks and mortar, share in the mineralogical composition the dominant component of gypsum.