Abstract: Layered modified sodium silicate crystal (Al-SKS-6) is a kind of excellent detergent additive made from modifying layered sodium silicate crystal (SKS-6).Al-SKS-6 was synthesized and characterized.Effects of pH,tempe-rature，and time on Ca²⁺/Mg²⁺ exchange property of Al-SKS-6 were investigated and kinetics thereof was studied.Exchange properties of Ca²⁺ and Mg²⁺ reached 352 mg/g and 405 mg/g respectively,which could satisfy the practical requirement of detergent when pH was about 10. Process of Al-SKS-6 exchanging Ca²⁺/Mg²⁺ was quite rapid and the exchange property at 5 min was equal to 90% at 30 min.Furthermore,the exchange process could reach equilibrium in 10 min and accorded to the pseudo second order kinetics equation and the exchange property of Al-SKS-6 to Ca²⁺/Mg²⁺ increased with increasing temperature.

Key words: layered modified sodium silicate crystal, Ca²⁺/Mg²⁺, kinetics