水杨羟肟酸在独居石矿物表面的吸附特性研究

研究独居石与捕收剂水杨羟肟酸的作用过程,考察了p H值、药剂浓度、时间等因素对矿物可浮性及水杨羟肟酸离子在矿物表面吸附热力学及动力学的影响。结果表明,独居石在中性和弱碱性条件下上浮率超过90%;水杨羟肟酸离子在独居石表面的吸附符合Langmuir模型,吸附过程吉布斯自由能变化-28.5 k J/mol,理论饱和吸附量为1.94×10~(-5)mol/g,吸附平衡常数为1.11×10~5L/mol。吸附过程平均吸附能19.5 k J/mol,说明水杨羟肟酸离子在独居石表面的吸附为化学吸附,吸附过程符合准二级动力学模型,速率常数5.3×10~4 g/(min·mol),捕收剂离子在矿物界面表膜中的扩散过程是浮选过程的控制步骤。

Adsorption properities of salicylic acid hydroxyl oxime on monazite surface

The flotation response of monazite towards salicylhydroxamic acid(SHA) and their interaction mechanism were investigated by micro-flotation and adsorption experiments. Micro-flotation results indicated that the SHA can float out over 90% monazite at neutral and weak alkaline conditions. Thermodynamics and kinetics properities during adsorption process were studied in detail by varying pH value,SHA concentration and adsorption time. The thermodynamic results demonstrated that the adsorption agreed well with Langmuir isotherm and the Langmuir constant, Gibbs free energy change and maximum adsorption capacity the were 1.11×105L.mol-1, -28.5kJ.mol-1, 1.91×10-5mol.g-1 respectively. The kinetic results showed that the adsorption process was well fitted by pseudo-second-order model and the sorptionSrate constant was 5.3×104 g.min-1.mol-1. The mean adsorption energy was 19.5kJ.mol-1, more than 16kJ.mol-1, suggesting that SHA might chemisorbed on the surface of monazite. The intraparicle diffusion was the main rate-limiting step.