表面化学修饰提升活性炭对金硫代硫酸根络离子的吸附性能研究

Large scale use of thiosulfate leaching of gold has not been achieved for the insignificant adsorption of thiosulfate gold complexes on active carbon. The preliminary investigation showed that thethiosulfate gold complexes in thiosulfate leaching liquor could be recovered by chemical modified active carbon . The different interaction between gold complexes and active carbon will be researched by structural analysis and computational chemistry in order to understand the reason of significant adsorption of cyanide gold complexe and insignificant adsorption of thiosulfate gold complexe on the active carbon. The gold complexes adsorption effects on the active carbon with different pore size and distribution will be investigated by adsorbtion tests. Further more, absorption characteristics of thiosulfate gold complexes on suitable pore active carbon modified with different methods such as oxidation-reduction and load of metal complex ion will be studied to improve active carbon adsorption performance to gold thiosulfate complex substantially. The gold sorption forms onto the modified active carbon surface would be determined by X-ray Diffraction and X-ray photoelectron spectroscopy(XRD 、XPS ）as well as other method to investigate the gold adsorption mechanism. Recovery of gold by the modified activated carbon in the pulp of thiosulfate leaching system of representative gold ore will be researched. The program of carborn in pulp(CIP )on thiosulfate gold leaching method would be established.The research results would be positive effect to commercialize use of thiosulphate gold leaching.

浸金矿浆中的金回收困难是硫代硫酸盐无毒提金技术产业化的最大瓶颈。前期研究表明表面化学修饰可增强活性炭对金硫代硫酸根络离子的吸附能力。本项目拟通过吸附实验、结构分析并辅以模拟计算研究炭的孔径及分布、活性官能团、表面化学性质对活性炭金硫代硫酸根络离子之间作用力的影响及机制，分析氰化提金活性炭不能有效吸附金硫代硫酸根络离子的本质原因，探讨可能解决的方法，查找适宜的指征基团；采用氧化、浸渍等方法对适宜孔径及分布的活性炭进行表面化学修饰,以期大幅提升其对金硫代硫酸根络离子的吸附性能，并进一步考察影响表面化学修饰炭吸附性能的主要因素；通过X射线衍射、光电子能谱等方法分析载金炭上金的吸附形态与分布，讨金吸附机理，进一步优化确定表面修饰方法；再采用典型金矿石的金搅拌浸出吸附、载金炭解析、活性炭再生实验，形成硫代硫酸盐表面修饰炭炭浆法（CIP）提金方案。为实现硫代硫酸盐提金技术产业化提供实验基础和理论依据。

硫代硫酸盐浸金法因其具有成本低、毒性小及对环境友好等优点成为了最有望替代氰化法的无氰提金技术。但活性炭难以回收硫代硫酸盐浸金液中的金，其发展受到了限制。提升活性炭对Au(S2O3)23-的亲和力，推进改性炭炭浆法（CIP）、炭浸法（CIL）在硫代硫酸盐提金技术中的应用，对该技术产业化具有重要意义。.本项目对活性炭进行表面修饰，并将其用于对Au(S2O3)23-的吸附。发现负载铁氰化物于活性炭表面、以硫醇类试剂对活性炭进行浸渍、以气相沉积硫脲对活性炭表面进行修饰均可有效增强活性炭对Au(S2O3)23-的亲和力。化学气相沉积硫脲表面修饰活性炭对金的负载量可达为11.85 kg/t，以2-巯基苯并噻唑、1-苯基-5-巯基四氮唑及2,5-二巯基噻二唑修饰所得的三种改性炭对金的负载量分别达到了18.40 kg/t、25.85 kg/t和25.55 kg/t。经改性-吸附-解吸-再改性-吸附循环后，金吸附的回收率高于85%，可满足硫代硫酸盐提金法产业化需要。.研究了活性炭表面修饰方法对Au(S2O3)23-吸附率及负载量的影响，优选得到对Au(S2O3)23-具有较高吸附性能的改性活性炭。以SEM、XRD、BET、FTIR、XPS等表征手段对其表面及结构性能进行了分析，探讨了改性炭对Au(S2O3)23-的吸附机理。发现气相沉积硫脲改性炭和以硫醇类试剂浸渍改性炭对Au(S2O3)23的吸附机理为配体交换机理，负载铁氰化物改性炭对Au(S2O3)23-的吸附机理为离子交换机理。.探讨了载金炭的解吸-循环再生工艺，进行了实际金矿矿石浸液中Au(S2O3)23-的吸附实验研究。结果表明，浸液中杂质离子对改性炭吸附Au(S2O3)23-吸附行为影响较大，但可通过调节浸液中氨/胺浓度等方式进行调控。.结果表明，通过表面修饰活性炭回收硫代硫酸盐金浸出液中金的研究为硫代硫酸盐提金产业化应用提供了实验基础和理论指导，具有良好的应用前景。