Abstract: Soluble silicate used for washing powder was prepared by the reaction of caustic soda with quartz sand from desert.Influences of technological conditions including material mix ratio (mass ratio of quartz sand to alkali),reaction time,and reaction pressure on Si/Na ratio (amount-of-substance ratio of SiO₂ to Na₂O) and deliquescent rate of SiO₂ were investigated.The optimal conditions were obtained as follows:material mix ratio was 2.1,reaction time was 8.0 h,and reaction pressure was 0.75 MPa.Si/Na ratio and the deliquescent rate of SiO₂ under the optimal conditions were 2.24 and 80.5%,respectively.

Key words: quartz sand, soluble silicate, Si/Na ratio, deliquescent rate of SiO₂