PROCESS FOR THE HYDROTHERMAL PRODUCTION OF SODIUM SILICATE SOLUTIONS IN A STATIC REACTION VESSEL

摘要

1. A process for the hydrothermal production of sodium silicate solutions having a ratio by weight of SiO2 to Na2 O of from 1 to 2.8:1 by reacting sand with aqueous sodium hydroxide solution under pressure at elevated temperature, followed by filtration, characterised in that the liquid phase of the reaction mixture is pump-circulated at temperatures in the range from 150 to 250 degrees C and under the saturated steam pressures corresponding to those temperatures through a bed of sand introduced into a static reaction vessel, resulting in the formation of a fluidized bed, and through a bypass pipe arranged outside the vessel until the concentration of SiO2 in the liquid phase has reached a value corresponding to the above-mentioned range.