Studies on the system sodium oxide-calcium oxide-silica-water

✍ Scribed by Blakeman, Elizabeth A. ;Gard, J. Alan ;Ramsay, Cameron G. ;Taylor, Harry F. W.

• Book ID: 102316775
• Publisher: Wiley (John Wiley & Sons)
• Year: 2007
• Tongue: English
• Weight: 379 KB
• Volume: 24
• Category: Article
• ISSN: 0375-9210
• DOI: 10.1002/jctb.2720240407

✦ Synopsis

Abstract

In hydrothermal reactions of lime and quartz with water or aqueous NaOH at 150 °C or 180 °C and Ca: Si = 0.83, the rate of reaction of the quartz increases with NaOH concentration. At 180 °C and Ca: Si = 0.83, the conversion into tobermorite of the semi‐crystalline calcium hydrosilicate initially formed occurs more slowly at NaOH concentrations of 0.15–2.00 M (NaOH: SiO~2~ = 0.05 to 0.63) than in water or 5 M‐NaOH. With long reaction times at 180 °C and Ca: Si = 0.83, increasing NaOH concentration causes pectolite to replace xonotlite as the main product. At very low water contents, NaCaHSiO~4~ is formed; this compound is conveniently made by grinding together solid NaOH, Ca(OH)~2~ and quartz in normally humid air and heating the mixture in a closed vessel at 180 °C.