The relationship between phase composition and conditions of sintering seawater derived magnesium oxide

Abstract

This study has focused on the favourable effect of the TiO 2 addition (1, 2 and 5 wt%) on the reduction of B 2 O 3 content during activated sintering of magnesium oxide from seawater at temperatures of 1400, 1500 and 1700°C for the duration of 1, 2 and 4 h. A mathematical model of dependence between the B 2 O 3 mass fraction in the sintered sample, the temperature of isothermal sintering, the isothermal sintering time and the mass fraction of TiO 2 added have been proposed. Magnesium oxide was obtained from seawater by substoichiometric precipitation, with the addition of 80% of dolomite lime as the precipitation agent. New phases formed in magnesium oxide samples were examined by the XRD and SEM/EDS analysis. The results indicate that during activated sintering of seawater-derived magnesium oxide with a TiO 2 addition, reactions of formation of Ca 2 B 2 O 5 , CaTiO 3 and Mg 2 TiO 4 took place simultaneously. The thermodynamics analysis of experimental results, based on the Onsager reciprocity relations (symmetry relations), was applied and phenomenological coefficients were calculated to describe the interference of these three irreversible processes. adhana(0123456789().,-volV)FT3 ](0123456789().,-volV)

Effect of Dilution and Electrolysis Time on Recovery of Mg2+ As Mg(OH)2 from Bittern by Electrochemical Method

“…Magnesium hydroxide, the intermediate of magnesium oxide, is used mainly in the pharmaceutical industry [15], antibacterial agent [16], refractory, water and wastewater treatment [17] and desulphurization of fuel gases [18]. The conversion process of Mg 2+ in the bittern into Mg(OH) 2 is generally accomplished by the addition of chemical reagents such as dolomite [19], ammonium hydroxide (NH 4 OH) [20], and sodium hydroxide (NaOH) [21]. In principle, Mg(OH) 2 can be obtained from bittern by an electrochemical method based on X The journal homepage www.jpacr.ub.ac.id p-ISSN : 2302 -4690 | e-ISSN : 2541 -0733 88 electrolysis reaction.…”