铝酸钠溶液中Al(OH)_3吸附草酸盐行为研究

Adsorption Behavior of Oxalate on Al(OH)_3 in Sodium Aluminate Solution

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.

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.