Synthesis and characterization of Sulfoaluminate-(Belite) cements from industrial residues
Pure calciumsulfoaluminate can be synthesized from a stoichio metric mixture composed of a calcium source, mainly calcium carbonate, an aluminum source as aluminum oxide and a sulfur source like anhydrite at temperatures above 1200℃.After intensive intergrinding of these raw materials and sintering at 1300℃ the formation of pure calciumsulfoaluminate is possible.Using oth er raw materials containing oxides like SiO2 (quartz) or some iron phases additional minerals are formed.These minerals are mainly C2 S (belite) and calciumaluminumferrite (brownmillerite) incorporating silicon and iron.In the presence of magnesium oxide additional minerals like periclase (MgO) and merwinite (C3 MS2) are crystallizing.Also the formation of gehlenite (C2AS) and solid solutions with akermanite-so called melilites-can be found.When insufficient sulfate is present in the raw meal CA and mayenite can be found in the different cement types.In this study mainly the use of industrial residues was investigated.Mixtures of brown coal fly ashes and limestone in definite proportions and sintering at temperatures of above 1200℃ leads to the formation of sulfoaluminate-belite cements.With var ying compositions mixtures enriched in gehlenite and merwinite were ob tained.Also the formation of brownmillerites or incorporation of iron in other cement phases can be observed depending on the composition of the raw meals.Using more chemically different industrial residues SA, SAB and SFAB cements can be found.
Calcium sulphoaluminate Yeelimite Brown coal fly ash Belite
P(o)llmann H. St(o)ber S. Schmidt R.
University of Halle/Saale,Halle,06120,Germany Bruker AXS,Karlsruhe,76187,Germany
国际会议
武汉
英文
366-384
2013-10-23（万方平台首次上网日期，不代表论文的发表时间）