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Pottery and ceramics have been an important part of human culture for thousands of years. From prehistoric storage jars to tiles on the space shuttles, pottery and ceramics have played a key role in innumerable human endeavors. The art of ceramics is one of the oldest known, dating to prehistoric times. Once heated (fired) to between 350⁰ and 800⁰C, the clay is converted to ceramic and will never dissolve again. Ceramic products are used as structural including bricks, pipes, floor and roof tiles, Refractories, such as kiln linings, gas fire radiants, steel and glass making crucibles, Whitewares, including tableware, wall tiles, pottery products and sanitary ware or technical,. | Part 4 Impregnation of Doping Materials 14 Effect of TÌƠ2 Addition on the Sintering Process of Magnesium Oxide from Seawater Vanja Martinac University of Split Faculty of Chemistry and Technology Croatia 1. Introduction Magnesium oxide is one of the most important materials used in the production of high-temperature-resistant ceramics. Due to its high refractory properties MgO melts at 2823 40 oC MgO ceramic is non-toxic and chemically inert in basic environments et elevated temperatures resistant to the effect of metal melts acid gases alkali slag neutral salts and react with carbon only above 1800 oC. Today in large-scale technicall processes magnesia MgO for refractories is produced from two sources natural and synthetic. Magnesia from natural sources constitutes 82 of the world s magnesia installed capacity. The dominant source is magnesite MgCO3 which occurs in both a macro and a cryptocrystalline forms. Less significant are dolomite CaCO3 -MgCO3 hydromagnesite 3MgCO3 Mg OH 2 3H2O brucite Mg OH 2 and serpentine Mg3 Si2O5 OH 4 . Synthetic materials are manufactured either from seawater or from magnesia rich brines. Magnesium oxide obtained from sea water is a high-quality refractory material and its advantages lie not only in the huge reserves of seawater 1 m3 contains 0.945 kg of magnesium but in the higher purity of the sintered magnesium oxide 98 MgO . The production of magnesium oxide from seawater is a well-know industrial process Bocanegra-Bernal 2008 Bonney 1982 Gilpin Heasman 1977 Heasman 1979 Maddan 2001 Martinac 1994 Petric Petric 1980 Rabadzhieva et al. 1997 and has been studied all over the world for a number of years. For most of the second half of the twentieth century seawater provided almost 50 of the magnesium produced in the western world and today it still remains a major source of magnesium oxide in many countries. The process involves the extraction of dissolved magnesium which has a concentration of around 1.3 g dm-3 in seawater Brown et .
