合成一种新型的表面活性剂——N-异丁氧羰基硫脲(iBCTU),对其结构进行红外和核磁共振表征,并考察其对黄铜矿的浮选性能以及在黄铜矿表面的吸附热力学和机理.浮选和吸附结果表明:在pH 3～11的范围内,iBCTU对黄铜矿具有良好捕收能力,且黄铜矿对iBCTU的吸附量随着温度的升高而增大.热力学分析表明:iBCTU在黄铜矿表面的吸附等温线符合Langmuir模型,吸附焓变△H为56.42 kJ/mol,熵变△S为284.76 J/(mol.K),吸附自由能变△G为-29.12 kJ/mol(298K),iBCTU在黄铜矿表面的吸附为自发、吸热化学吸附过程.XPS分析进一步说明iBCTU可能通过其硫代羰基的硫原子和-NH2基氮原子与黄铜矿表面的铜原子结合生成iBCTU-Cu(Ⅰ)表面络合物吸附在黄铜矿表面.
A novel surfactant,N-isobutoxycarbonyl thiourea (iBCTU) was synthesized and characterized by infrared spectroscopy,H nuclear magnetic resonance (HNMR) and C nuclear magnetic resonance (CNMR).Its flotation performance,adsorption thermodynamics and mechanism for the chalcopyrite were evaluated.The results of micro-flotation and adsorption tests show that iBCTU exhibits excellent hydrometallurgical performance for chalcopyrite under pH 3-11,and the adsorption capacity increases with increasing temperature.The adsorption isotherm agrees well with Langmuir model and the thermodynamics parameters AH (enthalpy change),AS (entropy change) and AG (free energy change) are 56.42 kJ/mol,284.76 J/(mol.K) and-29.12 kJ/mol (298K),respectively,which infers that the adsorption of iBCTU on the chalcopyrite surface is a spontaneous and endothermic chemisorption.The XPS results further demonstrate that iBCTU might bond with the copper atoms on the chalcopyrite surface through its sulfur (-C=S) and nitrogen (-NH2) atoms to form iBCTU-Cu(Ⅰ) surface complexes.
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