关键词: Lithium slag, FAU/LTA, Co-crystalline zeolite, Mother liquid, Detergent builder

Abstract: Co-crystalline zeolite FAU/LTA-0 was synthesized by hydrothermal method from lithiumslag. To make themost of excess silicon and alkali sources inmother liquid derived fromFAU/LTA-0, zeolite FAU/LTA-1bwas synthesized in the samemethodwith the use ofmother liquid by adding a certain amount of aluminumsource. Influences of different adding ways of aluminum source and recycling dosages of mother liquid on synthesis of zeolites FAU/ LTA with mother liquid were investigated. The phase, microstructure and thermostability of FAU/LTA-0 and FAU/LTA-1b were characterized by XRD, SEM and TG-DTA. The calcium and magnesium cation exchange capacities (CECs) of the zeolites were determined. The results have shown that co-crystalline zeolite can be synthesized with the use of mother liquid by adding aluminum source after 2 h of reaction. Compared with FAU/LTA-0, the crystal twinning structure of FAU/LTA-1b became weaker, the grain size was smaller, and the thermostability was better. With a lower dosage of mother liquid, the content of P-type impurity in product decreased significantly, and the content of LTA phase increased. The reuse rate of mother liquid can reach 48%. The CECs of FAU/LTA-1b-150 can reach 343 mg CaCO₃·g^-1 and 180 mg MgCO₃·g^-1, showing more excellent adsorption capacities than FAU/LTA-0 and commercial zeolite 4A. The full recycling use of mother liquid to synthesize zeolite FAU/LTA which can be applied for detergent not only improves resource utilization but also reduces production cost.

Key words: Lithium slag, FAU/LTA, Co-crystalline zeolite, Mother liquid, Detergent builder