Download Synthesis und Characterisation of Sorel Cement - Martin

Martin Luther Universität Halle-Wittenberg
Institut für Geowissenschaften
Mineralogie/Geochemie
Prof. Dr. Dr. H. Pöllmann
von-Seckendorff-Platz 3, 06120 Halle,
Tel: +49.345.5526111, Fax:+49.345.5527180,
e-mail: [email protected]
Synthesis und Characterisation
of Sorel Cement
Dipl. Min. Katrin Schollbach, Tel. 0345 55 26123, [email protected]
Sorel cements are named after their discoverer S. Sorel1 and consist of basic metal-salt hydrates;
basis is the ability of many water insoluble metal oxides to react with solutions of their salts. The so
obtained cement binder is characterised by high early strength, good abrasion resistance, low density
compared to OPC and stability against saline solutions. However, the industrial application of Sorel
cement has been limited due to its low water resistance. In order to solve this problem and to create a
new, versatile cement for special applications, syntheses of Sorel cements in the systems MgOMgCl2-H2O, MgO-MgSO4-H2O, MgO-Mg3(PO4)2-H2O, MgO-Mg(CH3COO)2-H2O and CaO-CaCl2-H2O
are carried out. Suitable compounds are chosen and optimised with respect to synthesis conditions,
raw materials, mix ratios and usage of additional ions. Additionally, the application of nano oxides will
be tested.
Sorel cements are synthesised by dissolving metal(II)-oxides in highly concentrated salt solutions2.
The Sorel phases are usually precipitated after two to three hours depending on temperature,
concentration and solution/solid ratio. The quality of the used metal(II)-oxides critically influences the
reaction and is mainly determined by crystallite size.
Lattice constants and crystal structures of sorel cement phases are known only in the systems MgOMgCl2-H2O und MgO-Mg(SO4)-H2O3. Compounds in these systems consist of edge-sharing MgO
octahedrons.
5Mg(OH)2·MgCl2·8H2O from 4M MgCl2-sol., Sol./MgO=100
and various Magnesiumoxides after 4d (MgO peaks red,
Mg(OH)2 peaks black)
Literatur:
1
System MgO-Mg(NO3)2-H2O with various Mg(NO3)2x6H2O
conc. und const. MgO percentage, 2M: Mg(OH)2 , 14M:
unknown compound
S. Sorel and M. Dumas, Comptes Rendus Hebdomadaires, 1867, 65, 102
2
T. Demediuk and W. F. Cole, Australian Journal of Chemistry, 1957, 10, 287-294
3
M. F. Hochella, K. D. Keefer and B. Dejong, Geochimica Et Cosmochimica Acta, 1983, 47, 2053-2058