Abstract: The adsorption equilibrium and kinetics of oxalate on Al(OH)₃ in sodium aluminate solution were studied by simulating the seed precipitation of the Bayer process， and the effects of initial oxalate concentration and the particle size of Al(OH)₃ on adsorption were also investigated. The results showed that Al(OH)₃ has a good adsorption ability on sodium oxalate. With increasing initial sodium oxalate concentration and decreasing particle size of Al(OH)₃， the equilibrium adsorption rate increases and the equilibrium adsorption time decreases. The adsorption capacity for different particle size of Al(OH)₃ is different due to the different specific surface area. The adsorption isotherm pattern of sodium oxalate on Al(OH)₃ fits the Freundlich model well and the adsorption process can be described by the pseudo-second-order equation. The adsorption of oxalate on Al(OH)₃ is a multilayer adsorption， associated with physical and chemical adsorption processes.

Key words: Al(OH)₃, oxalate, adsorption, equilibrium, kinetics