Stability of calcium silicate in basic solution
(School of Metallurgical Science and Engineering,
Central South University, Changsha 410083, China)
Central South University, Changsha 410083, China)
Abstract: Mixture of CaO and SiO2 was sintered at 1200 or 1400℃ according to the mole ratio of CaO/SiO2 of 1 or 2, and then calcium silicate was leached in pure caustic or soda solution. The results indicated that calcium silicate exists much more stably in caustic solution than that in soda solution, and CaO·SiO2 is more stable than β-2CaO·SiO2 whether in caustic solution or in soda solution. The increase of sintering temperature favored the stability of calcium silicate in the leaching process. When β-2CaO·SiO2 was leached in soda solution, the increase of leaching temperature and time resulted in decomposing of more calcium silicate. And when β-2CaO·SiO2 was leached in caustic solution at high temperature, much 2CaO·SiO2·H2O but little CaO·SiO2·H2O appeared in slag.
Key words: calcium silicate; stability; caustic/soda solution