The Effect of Small Additions of Water on the Reactions in the Mixture 6SiO₂.Na₂CO₃.CaCO₃

_{JSGT 1937 V21 T285-T298}

_{The effect of water on the reactions in a mixture containing sodium carbonate, calcium carbonate, and silica in the molecular proportions 1:1:6 has, been studied in the temperature range 700–1400°. It was found that additions of up to 16% water had no measurable effect on the rate of reaction at 700°, or on the process of sintering between 700° and 800°. Chemical examination of the product showed that addition of water had no effect on the amount of reacted lime or silica. Under the conditions of experiment in this investigation no appreciable hydrolysis of sodium carbonate with production, of hydroxide was observable at 700°, whilst it was but small at 800°. It was found that water has no effect on the melting and refining phenomena at temperatures of 1100–1300°. At 1400° the addition of 4·5% water reduces the seediness of the melt, but if 8% is added, the glass retains more seed. Experiments are recorded on the rate of loss of moisture from charges varying from 1 g to 15 lb, and for the rate of rise of temperature in a mass of batch mixture. At the centre of a 15 lb charge of dry batch mixture in a fireclay pot maintained at 1400°, the temperature only reached 600° after 22 min and 1350° after 55 min. These observations were applied to explain the course of events when moist batch mixture is heated.}

J. E. Stanworth & W. E. S. Turner