铝酸钠溶液中Al(OH)3吸附草酸盐行为研究

通过模拟拜耳法晶种分解过程研究了铝酸钠溶液中Al(OH)₃对草酸盐的吸附平衡和动力学行为，并考察了草酸盐初始浓度和Al(OH)₃粒度对吸附的影响规律. 结果表明:Al(OH)₃对草酸钠有较大的吸附能力，随草酸钠浓度的升高和Al(OH)₃粒度的细化，草酸钠吸附率随之升高，达到平衡的时间也相应缩短;不同粒度Al(OH)₃的吸附能力不同，这跟Al(OH)₃的比表面积有很大关系;Al(OH)₃对草酸钠的等温吸附符合Freundlich模型，吸附动力学符合准二级动力学方程，吸附行为为多分子层吸附，同时存在物理和化学吸附过程.

Adsorption Behavior of Oxalate on Al(OH)3 in Sodium Aluminate Solution

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.