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Kinds of Natural Fibres and Its Special Characteristics
Published in G. Mohamed Zakriya, G. Ramakrishnan, Natural Fibre Composites, 2020
G. Mohamed Zakriya, G. Ramakrishnan
Brucite is the mineral form of magnesium hydroxide; it has good anti alkaline properties. It is more stable in an alkaline medium than glass fibre. The moderate strength of this fibre can reach up to 900 MPa.31
Methods of exploration and investigation of the Magnesian raw material in Ukraine
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
The magnesium raw material basis of Ukraine will in the future require import of some amounts of high-quality magnesium raw material preferment of brucite Mg(OH)2 type. Brucite will be widely used not only for production of refractories, but also for fabrication of periclase and other magnesium products of supreme quality. Recently Russia, Turkey and China are the substantial suppliers of this raw material. The essential contribution to a solution of a problem of high-quality magnesium of raw material is realization of processing of magnesium salts from developing brine deposit Sivach. Use of Sivach brine enables to produce the high stability refractories with the MgO content 93-99 % (periclase type refractories), which one can be used in hyperthermal technologies. The Sivach brine provides Mg and Na salts, gypsum and other chemical components. Mg salts can be used also as the additive at fabrication of the relevant refractories. In world the share of ocean waters used in reception of magnesium yields is gradually increasing. In Ukraine the leaching of siliceous strata from the depths 1,700-3,000 m by wells, being realized in Dneprovo-Donezkoy cavity (the Chernigov and Poltava area), is recently noncommercial.
Stabilization and Solidification of a Clay Soil Contaminated with MTBE by Using MgO and Hydrated Lime
Published in Soil and Sediment Contamination: An International Journal, 2023
A. R. Estabragh, A. Ansar Shourijeh, K. Rezaei, A. A. Javadi, M. Amini
The final strengths of different samples were obtained from the strength-strain curves. The results of final strength versus curing time for mixtures of natural or contaminated soil with different percentages of MgO are shown in Figure 4. As shown in this figure, for a given percentage of MgO, the strengths of both the natural and contaminated soils are increased with increasing the curing time. These results are consistent with the results that were reported by Estabragh et al. (2022b). When MgO is mixed with soil, its hydration adsorbs the pore water into the spaces between the particles. At the first stage, ion exchange occurs between the MgO and particles of clay which results in a flocculated structure in the soil due to the reduction in the thickness of the diffuse double layer (DDL). Vandeperre, Liska, and Al-Tabbaa (2006) stated that the hydration of MgO is similar to the hydration of cement. During the hydration process, MgO is changed to Mg(OH)2, a product that is named brucite. Brucite reacts with CO2 and water and produces nesquehonite (MgCO3, 3 H2O), hydromagnesite (4MgCO3, Mg(OH)2, 4 H2O) and dypingite (4MgCO3, Mg(OH)2, 5 H2O). Among these products, nesquehonite has a higher strength than the other produced materials (Estabragh et al. 2022b; Schifano et al. 2007; Unluer and Al-Tabbaa 2011 and 2012). The carbonation process and production of the materials continue with time by adsorbing the water and CO2.