Ca4(Si04)(S04)CI 2 F. von Lampe Zentralinstitut fur Anorganische Chemie der Akademie der Wissenschaften der ODR 1199 Berlin, Rudower Chaussee 5 (Communicated by W. Wieker) (Received Oct. II, 1988) ABSTRACT DCA measurements and 28 d compressive strength determinations revealed that calcium silicate sulfate chloride Ca&(SiO4)(SO&)Cl 2, in contrast to chloroellestadite, is hydraulically active. The second DCA maximum resembles that of alite, but the heat evolution rate in this max~ mum is clearly lower. The compressive strength (approx.
25 MPa) ~ lower than known for C3S but definitely higher than found for C2S or anhydrite.
In view of these results the possibilities for producing a hydraulic binder with Ca4(SiO4)(SO&)Cl2 as a main component were checked. The main advantage of this binder is the possibility to use as raw materials partly or completely wastes, whose deposition otherwise causes environment pollution (gypsum from flue gas desulfurization in power stations, calcium chloride brine from potash fertilizer production, belite slurry from aluminum ore decomposition processes). The use of the new binder for reinforced concrete seems to be impossible in view of the corrosive properties expected.