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Beneficiation of Denizli - Acıgöl sodium sulphate ore by exploiting its structural properties
Published in Gülhan Özbayoğlu, Çetin Hoşten, M. Ümit Atalay, Cahit Hiçyılmaz, A. İhsan Arol, Mineral Processing on the Verge of the 21st Century, 2017
Sodium sulphate is an important industrial chemical. The main uses of sodium sulphate are in the pulp and paper, powder detergent, glass and textile dying industries. Sodium sulphate is widespread in occurrence and is a common constituent of many mineral waters, as well as seawater. Many of the saline lakes throughout the world contain varying amounts of sodium sulphate (Weisman, 1983). Sodium sulphate in its natural form is found as the hydrous salt mirabilite (commonly called glauber’s salt), and as thenardite, the anhydrous variety, mirabilite, Na2SO4.10H2O, contains 55,9 % water of crystallisation. It is efflorescence or spontaneous loss of water. On dehydration it changes to anhydrous form, Na2SO4. Thenardite, the anhydrous mineral, Na2SO4, contains 43,68 % Na2O and 56,32 % SO3.
Alkaline activators
Published in Caijun Shi, Pavel V. Krivenko, Della Roy, Alkali-Activated Cements and Concretes, 2003
Caijun Shi, Pavel V. Krivenko, Della Roy
Sodium sulphate, also known as disodium sulphate Na2SO4, in its natural form is found in two principal minerals: thenardite (anhydrous Na2SO4 ) and mirabilite Na2SO4⋅10H2O. Thenardite, the anhydrous form, was named after the French chemist, Louis Jacques Thenard (1777-1875). Mirabilite, the hydrous form, is commonly called Glauber’s salt as it was discovered by German chemist J. R. Glauber (1603-1668).
Persulfate activated with calcium peroxide to remediate RAFT soil contaminated with diesel in Arctic northern villages: on-site pilot scale study
Published in Environmental Technology, 2023
Taillard Vincent, Martel Richard, Pasquier Louis-César, Blais Jean-François, Mercier Guy
During the operation, PS was activated prior to its injection. Solid by-products were deposited at the bottom of the RES0 tank under the form of a compacted sludge. At the end of the operational period, air temperature dropped (and so SS stored in RES0) and translucent crystals (1–2 cm in size) assumed to be mirabilite [47] appeared on the oxidizing solution tank walls. These crystals had cumulated with the sludge, which volume reached 52 L with a density of 1.58 g/cm3 and containing about 47% w/w moisture. The dry sludge was composed of 15.4 ± 5.2% calcium, 16.0 ± 5.3% sodium, and 26.8 ± 1.0% sulphur. The high variability of Ca and Na content in the replicates suggested that the sludge was composed of several compounds containing sulphur, and which proportion varied depending on the sample location. Quantitative DRX analysis was carried out on three representative sludge samples and on an unaltered (neither dried nor milled) single crystal. Results confirmed that the crystal deposits were 100% mirabilite (Na2SO4.10H2O), which precipitates depending on temperature, when high concentration of sodium sulphate is reached in solution. The sludge was composed of 47.7 ± 1.7 glauberite (Na2Ca(SO4)2), an anhydrous sodium-calcium sulphate mineral formed in presence of sodium sulphate and calcium sulphate, 32.6 ± 0.4 bassanite (CaSO4.0.5H2O), the hemihydrate form of calcium sulphate, 4.7 ± 4.1 thenardite (Na2SO4) and 14.8 ± 2.7 anhydrous sodium sulphate mineral (Na2SO4).
Application of X-ray diffractometry and scanning electron microscopy to study the transformation of carnallite and thenardite to schoenite at 25 °C
Published in Chemical Engineering Communications, 2020
Qingyu Hai, Huaide Cheng, Haizhou Ma, Jun Li, Xiwei Qin
Based on the phase diagram for the quinary system, Na+, K+, Mg2+//Cl–, and SO42−-H2O at 25 °C (Jin et al., 1980), a direct path should exist to produce schoenite from carnallite and mirabilite/thenardite, which has rarely been reported. Mirabilite, which is known as a common evaporite from sodium-sulfate-bearing brines, exists widely around saline springs and along saline playa lakes (Hill, 1979). Mirabilite is unstable and dehydrates rapidly in dry air. The prismatic crystals convert to a white powder, thenardite. Carnallite is an evaporate mineral that usually forms in saline marine deposits or sedimentary basins. It is distributed widely as ore or is recovered from brine by saline manufacturers. Carnallite is a disproportionate salt, and water solutions yield KCl crystals and MgCl2 solution (Weedon et al., 2007a, 2007b; Wang et al., 2014b; Cheng et al., 2015). As can be seen that carnallite and mirabilite/thenardite are easily obtained from saline resources, so, a new and feasible path may exist to produce schoenite via carnallite and mirabilite/thenardite. Knowledge of the basic principle of the reaction of mirabilite/thenardite and carnallite may help to develop more effective strategies for producing schoenite through double-decomposition reactions.