PURPOSE: To produce crystalline sodium disilicate of a laminar structure having a molar ratio of SiO2 to Na2O of (0.9-2.1):1 and a water content of ≤0.3 wt.% and capable of obtaining the equal quality sodium disilicate over a long period of time.
CONSTITUTION: A water glass soln. is obtained by a reaction of sand and a caustic soda soln. in the molar ratio of SiO2 to Na2O of (2.0-2.3):1 and at 180-240°C and 10-30 bar pressure. The water glass soln. having at least ≤20 wt.% solid matter content is treated in a spray dryer using a hot wind of 200-300°C to form the powdery amorphous sodium disilicate having 15-23 wt.% water content and ≥300 g/l bulk density and the sodium disilicate is then pulverized and moreover the pulverized matter is treated in a rotary furnace at 400-800°C for 1-60 min.
GIYUNTAA SHIMUMERU
AREKUZANDAA TATSUPAA
KUNUUTO BAUAA
